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Neodymium Isotopic Study of Ocean Circulation during the Middle to Late Miocene Carbonate Crash

Permanent Link: http://ufdc.ufl.edu/UFE0021467/00001

Material Information

Title: Neodymium Isotopic Study of Ocean Circulation during the Middle to Late Miocene Carbonate Crash
Physical Description: 1 online resource (76 p.)
Language: english
Creator: Newkirk, Derrick R
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2007

Subjects

Subjects / Keywords: carbonate, caribbean, cas, circulation, crash, fish, miocene, neodymium, teeth
Geological Sciences -- Dissertations, Academic -- UF
Genre: Geology thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The term 'carbonate crash' describes an extensive dissolution event (or series of events) marked by low carbonate mass accumulation rates (MARs), which were originally observed in middle/upper Miocene sediments from the eastern equatorial Pacific and later discovered in western equatorial Atlantic and Caribbean Basin sediments. The timing of the crash suggests a change in global circulation patterns associated with the shoaling of the Central American Seaway (CAS) may have brought more corrosive bottom waters to this region. This study presents the first neodymium (Nd) isotopic data from this region which has been used to identify the source of bottom waters and the basic circulation patterns in the Caribbean during this gateway event. The total range for ENd values measured for fossil fish teeth over the interval of interest for site 998 (Yucatan Basin) is -6.6 to 0 from 14.1 to 9.0 Ma. Values for site 999 (Colombian Basin)range from -6.4 to -0.1 for 14.0 Ma to 9.1 Ma, and values for site 846 (Peru Basin) range from -3.75 to -1.65 for 14.1 Ma to 8.1 Ma. During the carbonate crash intervals (low carbonate MARs), the ENd values shift to more radiogenic values at all three sites. The radiogenic ENd values recorded in the Caribbean are similar to Pacific intermediate waters, which suggest the flow of Pacific water from west to east through the CAS into the Caribbean Basin. This flow pattern 11 agrees with several general ocean circulation models studying the shoaling of the Isthmus of Panama, as well as delta 13C data. Middle to late Miocene Caribbean carbonate crash episodes also appear to correlate to intervals of increased production of Northern Component Water (NCW). For the Caribbean, periods of enhanced conveyor circulation associated with enhanced NCW production appear to correlate with intervals when older, more corrosive intermediate Pacific waters passed through the CAS. Increased carbonate preservation in the Caribbean following the carbonate crash coincides with decreasing NCW production and less radiogenic ENd values, suggesting a gradual decline in Pacific waters flowing into the Caribbean Basin as the Isthmus of Panama shoaled. In the Pacific, increased NCW production resulted in a greater contribution of NCW to Circumpolar Water (CPW) and therefore older, more corrosive CPW, which ultimately formed more corrosive North Pacific Intermediate Water (NPIW) and Pacific Central Water (PCW). The southward migration of these water masses is documented by the progression of low carbonate MARs starting in the northern section of the eastern equatorial Pacific near the CAS at ~12 Ma, and moving further south to the location of site 846 by ~11.5 Ma. The carbonate crash interval at site 846 correlates with ENd values that shift upward to ~-2, a value consistent with the introduction of corrosive NPIW to this site.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Derrick R Newkirk.
Thesis: Thesis (M.S.)--University of Florida, 2007.
Local: Adviser: Martin, Ellen E.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2007
System ID: UFE0021467:00001

Permanent Link: http://ufdc.ufl.edu/UFE0021467/00001

Material Information

Title: Neodymium Isotopic Study of Ocean Circulation during the Middle to Late Miocene Carbonate Crash
Physical Description: 1 online resource (76 p.)
Language: english
Creator: Newkirk, Derrick R
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2007

Subjects

Subjects / Keywords: carbonate, caribbean, cas, circulation, crash, fish, miocene, neodymium, teeth
Geological Sciences -- Dissertations, Academic -- UF
Genre: Geology thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The term 'carbonate crash' describes an extensive dissolution event (or series of events) marked by low carbonate mass accumulation rates (MARs), which were originally observed in middle/upper Miocene sediments from the eastern equatorial Pacific and later discovered in western equatorial Atlantic and Caribbean Basin sediments. The timing of the crash suggests a change in global circulation patterns associated with the shoaling of the Central American Seaway (CAS) may have brought more corrosive bottom waters to this region. This study presents the first neodymium (Nd) isotopic data from this region which has been used to identify the source of bottom waters and the basic circulation patterns in the Caribbean during this gateway event. The total range for ENd values measured for fossil fish teeth over the interval of interest for site 998 (Yucatan Basin) is -6.6 to 0 from 14.1 to 9.0 Ma. Values for site 999 (Colombian Basin)range from -6.4 to -0.1 for 14.0 Ma to 9.1 Ma, and values for site 846 (Peru Basin) range from -3.75 to -1.65 for 14.1 Ma to 8.1 Ma. During the carbonate crash intervals (low carbonate MARs), the ENd values shift to more radiogenic values at all three sites. The radiogenic ENd values recorded in the Caribbean are similar to Pacific intermediate waters, which suggest the flow of Pacific water from west to east through the CAS into the Caribbean Basin. This flow pattern 11 agrees with several general ocean circulation models studying the shoaling of the Isthmus of Panama, as well as delta 13C data. Middle to late Miocene Caribbean carbonate crash episodes also appear to correlate to intervals of increased production of Northern Component Water (NCW). For the Caribbean, periods of enhanced conveyor circulation associated with enhanced NCW production appear to correlate with intervals when older, more corrosive intermediate Pacific waters passed through the CAS. Increased carbonate preservation in the Caribbean following the carbonate crash coincides with decreasing NCW production and less radiogenic ENd values, suggesting a gradual decline in Pacific waters flowing into the Caribbean Basin as the Isthmus of Panama shoaled. In the Pacific, increased NCW production resulted in a greater contribution of NCW to Circumpolar Water (CPW) and therefore older, more corrosive CPW, which ultimately formed more corrosive North Pacific Intermediate Water (NPIW) and Pacific Central Water (PCW). The southward migration of these water masses is documented by the progression of low carbonate MARs starting in the northern section of the eastern equatorial Pacific near the CAS at ~12 Ma, and moving further south to the location of site 846 by ~11.5 Ma. The carbonate crash interval at site 846 correlates with ENd values that shift upward to ~-2, a value consistent with the introduction of corrosive NPIW to this site.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Derrick R Newkirk.
Thesis: Thesis (M.S.)--University of Florida, 2007.
Local: Adviser: Martin, Ellen E.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2007
System ID: UFE0021467:00001


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c359f56945baf0cfa1408f7012f269729e6d5aff







NEODYMIUM ISOTOPIC STUDY OF OCEAN CIRCULATION DURING THE MIDDLE TO
LATE MIOCENE CARBONATE CRASH
























By

DERRICK RICHARD NEWKIRK


A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE

UNIVERSITY OF FLORIDA

2007

































2007 Derrick Richard Newkirk




























To my grandmother Addie Hair.









ACKNOWLEDGMENTS

I would like to sincerely thank Dr. Ellen Martin for her continued guidance on this project.

Not only is she a great mentor, but also a good friend and a pleasure to work with. Thanks also

go to my committee members Dr. David Hodell and Dr. John Jaeger for their advice and review

of this thesis. Thanks also to Dr. Philip Neuhoff for the many insightful conversations we had

pertaining to this research.

I am also very grateful for the financial support that was provided by the NSF SGR grant

awarded to Dr. Ellen Martin, the Department of Geological Sciences, and Graduate Student

Council.

Special thanks go to Susanna Blair for her guidance and continuous help in the lab at the

beginning of my graduate career. Also, I would like to thank Dr. George Kamenov for his

assistance in the lab, help with analysis, and suggestions for streamlining laboratory procedures.

I would also like to thank Wendell Phillips, Tracy King, Nicole Andersen and the many others

who have helped me in the laboratory.

Finally, I would like to thank my family and friends. Thanks go to Pat and Rick Newkirk

for their unfaltering love and support. Thanks go to Ryan Newkirk for being a great friend and a

very supportive brother. Thanks go to Scottie Andre for playing a huge role in my upbringing

and being a good role model. Thanks go to Laura Ruhl for her never ending love,

encouragement, and support throughout this process. Thanks go to my many wonderful friends

in the Department of Geological Science at UF, especially Jonathan Hoffman, PJ Moore,

Branden Kramer, Kris Crocket, Mike Ritorto, Gillian Rosen, and Dorsey Wanless. Thanks to

Dr. Gabriel Filippelli for his guidance, friendship, and encouragement to continue on to graduate

school. Thanks to Dr. Jennifer Latimer for her guidance, friendship, and invaluable lab guidance

that she gave me as an undergraduate researcher. And last but not least thanks go to all of my









wonderful friends outside of the department and from my hometown, especially Jason Wright,

Adam Faust, Judd Sparks, Dr. Gifford Waters, Erica Roberts, Carlos Zambrano, and Ryan

Fleming.









TABLE OF CONTENTS

page

A CK N O W LED G M EN T S ................................................................. ........... ............. .....

LIST O F TA BLE S ......... .... ........................................................................... 8

LIST OF FIGURES .................................. .. ..... ..... ................. .9

A B S T R A C T ......... ....................... ............................................................ 10

CHAPTER

1 INTRODUCTION ............... .......................................................... 12

2 B A CK G R O U N D .......................................... ................ ......................... .... 17

2.1 Neodymium Isotope Systematics .................................. .....................................17
2 .2 A archives of N d Isotopes ......................................................................... ....................18
2.3 Carbonate M AR........................... .................. ........... 20
2 .4 G general O cean C circulation ....................................................................... ..................20
2.5 Caribbean Basin Tectonic Setting ............................................................................. 22
2.6 M odem Caribbean Basin Circulation ...................................................... .................23
2 .7 O cean C circulation M models ....................................................................... ...................23
2 .8 D description of Sam ple Sites...................................................................... ..................24
2 .8.1 O D P Site 846B ................. .................................. ................ .. ........... 24
2.8.2 ODP Site 998A ................. ............... ......... ............. .... ....... 25
2.8.3 ODP Site 999A ................. ............... ....................... .... ....... 26
2 .8 .4 A g e M models ................................................................2 6

3 METHODS .........................................30

3.1 Fossil Fish Teeth Sam ple Preparation ........................................ ......................... 30
3.2 C olum n C hem istry ............................................. .............................. .. ............ 30
3 .3 N d A n aly sis ................................................................3 0

4 R E SU L T S .............. ... ................................................................32

4.1 N eodym ium Isotopic R atios ..................................................................... ..................32
4.2 ENd C om pared to C arbonate M A R ........................................................................ ...... 33

5 D ISC U S SIO N ..............................................................................................40

5.1 The Source of Caribbean Basin ENd Values in the Middle/Late Miocene ......................40
5.2 Circulation during the Caribbean Pre-Crash and Pre-Crash Transition .........................43
5.3 The C aribbean C arbonate C rash .............................................................................. .... 44
5.4 Circulation during the Caribbean Post-Crash Transition and Post-Crash ......................48









5.5 T he P pacific C arbonate C rash ........................................ .............................................49

6 C O N C L U SIO N S ................. ......... ................................ .......... ........ ..... .... ...... .. 62

L IST O F R E F E R E N C E S .............................................................................. ...........................64

B IO G R A PH IC A L SK E T C H .............................................................................. .....................76
















































7









LIST OF TABLES


Table page

4-1 Nd isotopes of Fossil Fish Teeth from ODP Site 846..................... .............. ............... 37

4-2 Nd isotopes of Fossil Fish Teeth from ODP Site 998.................................................... 38

4-3 Nd isotopes of Fossil Fish Teeth from ODP Site 999..................... .............. ............... 39









LIST OF FIGURES


Figure page

1-1 Plate reconstruction................................................ .......... .... ...... .. ............16

2-1 Simplified reconstruction of the Caribbean Region illustrating the locations of sites
998 and 999 from this study ...................................................................... ...................28

2-2 Carbonate MAR records for sites 846, 998 and 999 from 8 to 14 Ma
29

4-1 ENd values from site 846 in the eastern equatorial Pacific, sites 999 and 998 in the
C aribbean B asin plotted versus depth................................................................... .......35

4-2 ENd values and carbonate MARs from site 846 in the eastern equatorial Pacific and
sites 999 and 998 in the Caribbean Basin spanning from 8 to 14.5 Ma. .........................36

5-1 ENd values and ash MARs from sites 999 and 998 in the Caribbean Basin spanning
from 8 to 14 .5 M a. ....................................................... ................. 5 1

5-2 ENd values from sites 998 and 999 in the Caribbean Basin, site 846 in the eastern
equatorial Pacific, Fe-Mn crusts from the North Atlantic, Straits of Florida, North
Pacific, central equatorial Pacific ............................................. ............................. 52

5-3 Nd and 13C values from site 998. ...... ........................... ......................................53

5-4 Nd and 13C values from site 999. ...... ........................... ......................................54

5-5 Flow patterns of Atlantic and Pacific waters during the Pre-Crash/Pre-Crash
T transition intervals...............................................................................55

5-6 ENdvalues from sites 998 and 999 in the Caribbean Basin spanning from 8 to 14.5
Ma. 56

5-7 ENd values from site 998, carbonate MAR, and %NCW .................................................57

5-8 ENd values from site 999, carbonate MAR, and %NCW .................................................58

5-9 Flow patterns of Atlantic and Pacific waters during the Carbonate Crash interval...........59

5-10 Flow patterns of Atlantic and Pacific waters during the Post-Crash Transition/Post-
C rash interv als.. .................................................................................60

5-11 Dissolved oxygen profile from the Pacific. ............................................ ............... 61









Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science

NEODYMIUM ISOTOPIC STUDY OF OCEAN CIRCULATION DURING THE MIDDLE TO
LATE MIOCENE CARBONATE CRASH

By

Derrick Richard Newkirk

August 2007

Chair: Michael R. Perfit
Major: Geology

The term "carbonate crash" describes an extensive dissolution event (or series of events)

marked by low carbonate mass accumulation rates (MARs), which were originally observed in

middle/upper Miocene sediments from the eastern equatorial Pacific and later discovered in

western equatorial Atlantic and Caribbean Basin sediments. The timing of the crash suggests a

change in global circulation patterns associated with the shoaling of the Central American

Seaway (CAS) may have brought more corrosive bottom waters to this region. This study

presents the first neodymium (Nd) isotopic data from this region which has been used to identify

the source of bottom waters and the basic circulation patterns in the Caribbean during this

gateway event.

The total range for ENd values measured for fossil fish teeth over the interval of interest for

site 998 (Yucatan Basin) is -6.6 to 0 from 14.1 to 9.0 Ma. Values for site 999 (Colombian Basin)

range from -6.4 to -0.1 for 14.0 Ma to 9.1 Ma, and values for site 846 (Peru Basin) range from

-3.75 to -1.65 for 14.1 Ma to 8.1 Ma. During the carbonate crash intervals (low carbonate

MARs), the ENd values shift to more radiogenic values at all three sites. The radiogenic ENd values

recorded in the Caribbean are similar to Pacific intermediate waters, which suggest the flow of

Pacific water from west to east through the CAS into the Caribbean Basin. This flow pattern









agrees with several general ocean circulation models studying the shoaling of the Isthmus of

Panama, as well as 613C data.

Middle to late Miocene Caribbean carbonate crash episodes also appear to correlate to

intervals of increased production of Northern Component Water (NCW). For the Caribbean,

periods of enhanced conveyor circulation associated with enhanced NCW production appear to

correlate with intervals when older, more corrosive intermediate Pacific waters passed through

the CAS. Increased carbonate preservation in the Caribbean following the carbonate crash

coincides with decreasing NCW production and less radiogenic ENd values, suggesting a gradual

decline in Pacific waters flowing into the Caribbean Basin as the Isthmus of Panama shoaled.

In the Pacific, increased NCW production resulted in a greater contribution of NCW to

Circumpolar Water (CPW) and therefore older, more corrosive CPW, which ultimately formed

more corrosive North Pacific Intermediate Water (NPIW) and Pacific Central Water (PCW). The

southward migration of these water masses is documented by the progression of low carbonate

MARs starting in the northern section of the eastern equatorial Pacific near the CAS at -12 Ma,

and moving further south to the location of site 846 by -11.5 Ma. The carbonate crash interval

at site 846 correlates with ENd values that shift upward to --2, a value consistent with the

introduction of corrosive NPIW to this site.









CHAPTER 1
INTRODUCTION

The term "carbonate crash" was coined by Lyle et al. (1995) to describe an extensive

dissolution event (or series of events), marked by low carbonate mass accumulation rates (MAR)

during the middle/late Miocene that were observed during Ocean Drilling Program (ODP) Leg

138 in the eastern equatorial Pacific (Farrell et al., 1995; Lyle et al., 1995). Subsequently,

carbonate crash events have also been documented in the western equatorial Atlantic (Leg 154;

King et al., 1997; Shackleton and Crowhurst, 1997), and the Caribbean (Leg 165; Roth et al.,

2000) (Figure 1-1). Theories for the carbonate crash include: 1) increased productivity resulting

in enhanced decay (oxidation) of organic matter on the seafloor, or 2) a change in global

thermohaline circulation that introduced more corrosive bottom water to the equatorial region.

Lyle et al. (1995) noted that increased surface productivity and the associated production

of acid in the deep ocean during the degradation of large quantities of organic carbon would lead

to more corrosive bottom waters, resulting in a decrease in carbonate MAR. However, Lyle et

al. (1995) argued against this mechanism based on a lack of evidence for increased Corg MAR at

the time of the carbonate crash in the eastern equatorial Pacific, as well as a lack of a covariance

between carbonate and opal MARs. Specifically, Lyle et al. (1995) believed increased surface

productivity and associated deep water acidity should result in an increased Corg MAR and opal

MAR, and decreased carbonate MAR.

Alternatively, the carbonate crash may have resulted from a change in deep ocean

circulation. In this scenario, intervals of low carbonate MAR are linked to the presence of more

corrosive intermediate and deep water masses at sites around the Caribbean region that supply

deep waters to the Caribbean Basin (Roth et al., 2000; Lyle et al., 1995; Farrell et al., 1995). The









timing of the crash also suggests changing circulation patterns may have been associated with the

shoaling of the Central American Seaway (CAS).

Openings and closings of oceanic gateways have been associated with reorganizations of

ocean circulation and have been linked to dramatic climatic events throughout geologic time. An

example of this is the opening of the Tasman Seaway and the Drake Passage, which have been

linked to the onset of the Antarctic Circumpolar Current (ACC), the thermal isolation of

Antarctica, and the development of ice sheets on Antarctica (Kennett et al., 1974; Kennett, 1977;

Exon et al., 2002; Scher and Martin, 2006).

Previous studies of the effect of the closure of the CAS have focused on large- scale

changes in surface ocean circulation and the resulting impact on climate (Keigwin, 1982; Keller

et al., 1989; Coates et al., 1992; Moore et al., 1993; Haug and Tiedemann, 1998). However, this

closure likely impacted deep water circulation patterns as well. Closure presumably redirected

warm, saline surface waters from the Gulf of Mexico to the North Atlantic, thereby increasing

the salinity and density of the deep water formed in the Norwegian-Greenland-Labrador Seas.

This increase in North Atlantic Deep Water (NADW) production would have occurred at the

expense of North Atlantic Intermediate Water (NAIW), and the reduced NAIW would have been

compensated by northward migration of Antarctic Intermediate Water (AAIW). In this scenario,

the water mass flowing over the shallow sills separating the Caribbean from the Atlantic would

depend on the position of the boundary between these two intermediate water masses.

According to Roth et al. (2000), the water mass that overflowed the shallow to intermediate sills

and filled the deep Caribbean during times of enhanced carbonate preservation was primarily

sourced from the north, while southern sourced waters dominated during corrosive intervals.









In this scenario, the Southern Ocean becomes the primary location for deep-water

formation during times of decreased NADW production. Thus, the deep water in the Pacific

travels a shorter distance resulting in a water mass with higher oxygen and lower nutrient levels.

A similar process is observed in the eastern equatorial Pacific during glacial stages, which are

accompanied by weaker NADW production. Le et al. (1995) observed greater carbonate

preservation in the eastern equatorial Pacific during glacial stages and greater dissolution during

interglacial. When NADW production is strong, the deep water in the Pacific has to travel from

the North Atlantic. This longer travel path allows for more oxidation of organic matter, resulting

in increased concentrations of CO2 and nutrients, while decreased oxygen concentrations, and

older, more corrosive bottom water in the eastern equatorial Pacific.

This mechanism for the carbonate crash presented by Roth et al. (2000) is based on a

model developed by Haddad and Droxler (1996) to account for Pleistocene deposits in the

Caribbean that alternate between low carbonate accumulation during interglacial periods, and

carbonate deposition during glacial periods. Haddad and Droxler (1996) suggested that high

rates of NADW production during interglacial periods resulted in corrosive AAIW overflowing

the Caribbean sill and filling the Caribbean Basin, while decreased NADW production during

glacial periods resulted in NAIW overflowing the Caribbean sill and filling the Caribbean Basin.

Roth et al. (2000) attempted to use carbon isotopic data to identify the source of water entering

the Caribbean Basin and test this theory. They interpreted changes in 613C based upon the

assumption that either NAIW or AAIW was overflowing the sill to fill the Caribbean Basin, but

they could not identify a specific water mass with this proxy. Carbon isotopes can give an

indication of the age of the water mass, but they are not a unique proxy for water mass because

they are not conservative tracers (Kroopnick, 1985). In addition, carbon isotopic data are









generally recovered from foraminifera, which are rarely preserved during dissolution events

(Shackleton and Hall, 1995, 1997; Roth et al., 2000).

The goal of this study is to use neodymium (Nd) isotopes preserved in fossil fish teeth to

test theories about ocean circulation during the middle/late Miocene carbonate crash.

Neodymium isotopes were used because they are generally viewed as "quasi-conservative"

tracers of water masses, meaning they reflect the initial signal of the source region, but can be

modified by weathering inputs during circulation (Frank et al., 2003; Goldstein and Hemming,

2003). The end-member Nd isotopic compositions of the water masses in the Miocene are

relatively well constrained by published data for Fe-Mn crusts and fish teeth (Burton et al., 1997

and 1999; Ling et al., 1997; O'Nions et al., 1998; Martin and Haley, 2000; Frank et al., 2002;

van de Flierdt et al., 2004; Scher and Martin, 2004). In addition, fossil fish teeth are abundant

throughout the dissolution events, making them excellent archives to reconstruct paleocirculation

during these events.

Results of this research support the hypothesis that changes in deep water circulation are

associated with the carbonate crash intervals in the Caribbean and Pacific; however, the most

corrosive bottom waters appear to be derived from the Pacific rather than the Atlantic. This

scenario suggests west to east flow through the CAS in the middle Miocene in response to the

shoaling of the CAS and Northern Component Water (NCW) production.










180i


180l


-150'


-B '


-120'


-BO"


-30'


-30"


Plate reconstruction from the Ocean Drilling Stratigraphic Network
(www.odsn.de) with ODP and Ferromanganese Crust Locations discussed
in this study.


BO'




3D"









-a o


-3E"


-6D"


ED"




3D"










-3E"




-BO"


10 Ma Reconstruction


Figure 1-1.









CHAPTER 2
BACKGROUND

2.1 Neodymium Isotope Systematics

The light REE (Rare Earth Element) Neodymium (Nd) has seven isotopes. 143Nd is the

radiogenic daughter product of 147Sm (half-life = -1.06x1011 years), which is produced by alpha

decay. 144Nd is used as a reference because it is a stable isotope, thus the number of atoms

should not change as long as the system remains closed. The143Nd/144Nd ratio is reported as SNd

in order to report small but significant variations as whole numbers. ENd is calculated using the

equation:

ENd(0)=[(143Nd/144Nd)sample/(143Nd/144Nd)HUR-] 104

where CHUR (Chondritic Uniform Reservoir) equals the bulk earth 143Nd/144Nd of 0.512638

(DePaolo and Wasserburg, 1976).

The primary sources of Nd to seawater are continentally derived dust, volcanic ash,

resuspended detrital sediments, and riverine inputs in the form of either dissolved or particulate

material (Goldstein and Jacobsen, 1988; Elderfield, 1988; Spivack and Wasserburg, 1988;

Bertram and Elderfield, 1993; Greaves et al., 1994; Henry et al., 1994; Jeandel et al., 1995,

Albarede et al., 1997; Frank, 2002; Tachikawa et al., 1999 and 2003). Hydrothermal sources of

Nd to the ocean are insignificant, because Nd is quantitatively scavenged by oxides near the mid-

ocean ridge (Michard, 1983; German et al., 1990). Nd concentrations in seawater are fairly low,

-4pg/g in deep water, because Nd ions are relatively insoluble and extremely particle reactive.

In a situation that has been termed the Nd Paradox, Nd concentrations vary along the path of the

global conveyor belt, but Nd isotopes behave as conservative tracers (Goldstein and Hemming,

2003; Lacan and Jeandel, 2001; Jeandel et al., 1995, 1998; Tachikawa et al., 1999a, 1999b;

Bertram and Elderfield, 1993). Specifically, Nd concentrations are low in surface waters, but









higher in deep waters, and concentrations in the Pacific are higher than the Atlantic (Goldstein

and Hemming, 2003); however, Nd isotopes in modern core tops correlate well with salinity, a

conservative property in seawater (See review in Goldstein and Hemming, 2003).

Another important characteristic of Nd is that its residence time in seawater is 600-1000

years (Tachikawa et al., 1999; Elderfield and Greaves, 1982; Piepgras and Wasserburg, 1985;

Jeandel et al., 1995); which is shorter than the mixing time of the ocean at -1500 years

(Broecker and Peng, 1982). Due to this relatively short residence time, different ocean basins

have distinct Nd isotopic ratios (Table 1), which also vary vertically within the water column

(Piepgras and Wasserburg, 1987; Bertram and Elderfield, 1993; Jeandel, 1993). Modern NADW

has an ENd value of- -14, which reflects the weathering of Archean age rocks from the North

American craton (Piepgras and Wasserburg, 1987). Modem Pacific deep water has an ENd of -

4, which is the result of young, circum-Pacific volcanogenic sources (Piepgras and Jacobsen,

1988), while modern North Pacific Intermediate Water (NPIW) reflects an even stronger

influence from radiogenic volcanic material and has an Nd value of -2.5 (Piepgras and

Jacobsen, 1988). Finally, Antarctic Bottom Water (AABW) and Antarctic Intermediate Water

(AAIW) have ENd of -8 (Piepgras and Wasserburg, 1982; Jeandel, 1993), which represents

mixing of the Atlantic and Pacific water masses. For comparison, the analytical uncertainty for

Nd isotopic measurements for this study is + 0.35 ENd units. Therefore, the values for the various

end members are analytically distinct.

2.2 Archives of Nd Isotopes

Sedimentological archives such as ferromanganese (Fe-Mn) crusts and nodules, Fe-Mn

oxide coatings, and fossil fish teeth have been used to estimate the ENd values of past water

masses. Data from Fe-Mn crusts and nodules illustrate that the major ocean basins have distinct

isotopic compositions (Albarede and Goldstein, 1992; Abouchami et al., 1997; Burton et al.,









1997; Ling et al., 1997; Frank and O'Nions, 1998; Frank et al., 1999 and 2002; von Blackenburg

and Igel, 1999); however, Fe-Mn crusts yield very low resolution records due to their slow

growth rates (1-15mm/Myr; Segl et al., 1984; Puteanus and Halback, 1988). In addition, the

crusts have a sparse distribution, which inhibits large-scale sampling because they only grow

where sedimentation rates are extremely slow or currents sweep away hemipelagic sediment.

Finally, age control for Fe-Mn crusts, which are dated using Be, is poor beyond 10 Ma because

10Be has a half-life of 1.5 x 106 years. Overall, the slow growth rate of the Fe-Mn crusts records

long-term trends and variations in ocean circulation, but they do not record the more rapid shifts

in circulation that are frequently associated with climatic events because their signal is integrated

over time.

Fossil fish teeth, on the other hand, can be dated accurately with the surrounding sediment

using magnetostratigraphy, biostratigraphy, and chemostratigraphy, thereby allowing the

development of higher resolution records. Fossil fish teeth, which are composed of

hydroxyflourapatite, have been shown to be effective recorders of bottom water Nd isotopic

values (Elderfield and Pagett, 1986; Martin and Haley, 2000; Thomas et al., 2003; Martin and

Scher, 2004; Thomas, 2004; Scher and Martin, 2006). The hydroxyapatites of living fish teeth

have Nd concentrations in the ppb range (Wright et al., 1984; Shaw and Wasserburg, 1985),

while the hydroxyfluorapatite of fossil fish teeth have Nd concentrations of 100 to 1000 ppm

(Wright et al., 1984; Shaw and Wasserburg, 1985; Staudigel et al., 1985; Martin et al., 1995).

Fossil fish teeth appear to incorporate Nd during the early diagenetic transformation of

hydroxyapatite to hydroxyfluorapatite at the sediment-water interface, while the teeth are still in

contact with ocean bottom waters (Wright et al., 1984; Shaw and Wasserburg, 1985; Staudigel et

al., 1985; Martin et al., 1995; Martin and Haley, 2000; Martin and Scher, 2004). Martin and









Haley (2000) have demonstrated that fossil fish teeth record similar isotopic ratios to Fe-Mn

crusts when they are exposed to similar bottom waters. Given evidence that the initial SNd values

are preserved over time (Martin and Scher, 2004), the Nd signals from fossil fish teeth have been

used by Scher and Martin (2004, 2006), Thomas et al. (2003), Via and Thomas (2006), and

Thomas and Via (2007) to track paleocirculation.

2.3 Carbonate MAR

Carbonate mass accumulation rates (CO3 MARs) are determined by the following

equation:

MAR x CaCO3wt% x 100 = CO3 MAR

To calculate the CO3 MAR, the bulk mass accumulation rate (bulk MAR) and the calcium

carbonate weight content (CaCO3wt%) must be known. The bulk MARs were calculated by

multiplying dry bulk density (grams of dry sediment per wet volume in cubic centimeters) by a

calculated linear sedimentation rate (m/m.y.) (Roth et al., 2000). The CaCO3wt% was

determined for each sample using a carbonate bomb (Roth et al., 2000). Mass accumulation

rates and carbonate mass accumulation rates for this study were taken from Roth et al. (2000) for

the two Caribbean Basin sites (998 and 999), and from Farrell et al. (1995) for eastern equatorial

Pacific (site 846).

It is important to use carbonate MAR rather than CaCO3wt% to identify changes in the

carbonate system, because CaCO3wt% is influenced by dilution from other fractions such as

terrigenous matter, volcanic ash, and/or silica.

2.4 General Ocean Circulation

The modern general ocean circulation model is controlled by the sinking of cold, saline

surface waters in the high latitudes. Initially, water in the desert latitudes of the Atlantic

becomes warm due to solar radiation and saline due to evaporation. This warm-saline water then









moves north into the Norwegian-Greenland Sea as part of the Gulf Stream. As the water travels

into the North Atlantic it cools. When the water finally reaches the Norwegian-Greenland Sea it

cools until it becomes dense enough to set up an inverse density gradient, allowing the dense

overlying water mass to sink. This sinking water mass mixes with Labrador Sea water and

becomes North Atlantic Deep Water (NADW), which travels along the western margin of the

Atlantic and ultimately mixes with Antarctic Bottom Water (AABW) in the Antarctic

Circumpolar Current (ACC) to form Circumpolar Deep Water (CDW). This mixture eventually

flows northward into the Indian Ocean and Pacific Ocean. Along its circulation paths in the

Indian and Pacific Oceans CDW mixes upward with intermediate and surface waters. These

Intermediate and surface waters then flow south from the north Pacific to the south Pacific as

either North Pacific Intermediate Water (NPIW) or Pacific Central Water (PCW). The

southward flowing water leaves the Pacific Ocean either through the Indonesian Seaway or the

Drake Passage, ultimately flowing back into the Atlantic Ocean. Once these waters enter the

Atlantic Ocean, they follow the surface gyre circulation back to the equatorial region, thereby

starting the cycle over again. This circular path of water has been termed the "global conveyor"

by Broecker and Peng (1982) and takes approximately 1,500 years to complete (Broecker and

Peng, 1982).

The global conveyor can be altered by the closing/opening of oceanic gateways or the

introduction of fresh water. The CAS began closing during the middle to late Miocene creating a

barrier between the equatorial Atlantic and Pacific Oceans (Roth et al., 2000). The resulting

change in circulation may have affected the redistribution of heat and nutrients throughout the

ocean.









2.5 Caribbean Basin Tectonic Setting

Today the Caribbean Basin is bound by Central America to the west, the Lesser Antilles

and Aves Swell to the east, and the Nicaragua Rise and Greater Antilles to the north (Droxler et

al., 1998). The Aves Swell has behaved as a remnant arc since -55 Ma (Bird et al., 1993), and

according to Droxler et al. (1998) the topographic highs experienced neritic conditions from -50

- 15 Ma based on seismic surveys, drilling, and dredging, and then deeper conditions after 15

Ma. The two intermediate depth passageways (Windward Passage (1500 m) and the Anegada-

Jungfern Passage (1800m) (Figure 2-1) were the result of accelerated subsidence of the Aves

Swell to depths of 600 m to 1200 m during the middle Miocene (Pinet et al., 1985; summarized

in Droxler et al., 1998).

The Nicaragua Rise is a series of carbonate banks and barrier reefs that created a

prominent barrier to circulation during the Oligocene to middle Miocene in the Caribbean and

spanned from Nicaragua and Honduras to Jamaica (Lewis and Draper, 1990; Droxler et al., 1992,

1998; Cunningham, 1998) (Figure 2-1). According to Droxler et al. (1992), foundering of the

Nicaragua Rise occurred in the middle Miocene (-15-12 Ma), but could have begun as early as

late early Miocene (20-15 Ma). Faulting along the rise led to the opening of the north/south

oriented Pedro Channel and the northern part of the Walton Basin (Cunningham, 1998).

Using benthic foraminiferal assemblages from Atrato Basin located in the NW corner of

South America, Duque-Caro (1990) suggested that the Isthmus of Panama shoaled to a depth of

-2000 m by -15.9 15.1 Ma (ages adjusted to Shackleton et al., 1995a) and to a depth of -1000

m between 12 10.2 Ma (ages adjusted to Shackleton et al., 1995a). Shoaling of the Isthmus of

Panama to 100 m occurred by 4.6 Ma and final closure of the Central America Seaway occurred

by -3.5 Ma was suggested by Haug and Tiedemann (1998) based on a salinity increase recorded

in planktonic foraminifera.









2.6 Modern Caribbean Basin Circulation

The flow of shallow waters into the Caribbean Basin is controlled by both changes in

meridional overturning in the North Atlantic and changes in the position of the Intertropical

Convergence Zone (ITCZ) (Johns et al., 2002). According to Johns et al. (2002), almost all of

the wind driven flow into the Caribbean occurs north of 15N (north of Martinique). During the

summer a cyclonic circulation cell sets up southeast of the Lesser Antilles blocking the flow of

the Guyana Current into the Caribbean (Muller-Karger et al., 1989) while the ITCZ is located at

its northernmost position (6-10N) (Philander and Pacanowski, 1986).

Intermediate depth sills that extend from Venezuela to the Greater Antilles restrict flow

from the Atlantic into the Caribbean. The two most important connections today are the

Windward Passage (1500 m) and the Anegada-Jungfem Passage (1800m) (Pinet et al., 1985;

Figure 2-1). Because of these sills, bottom water in the Caribbean Basin is sourced by

intermediate depth waters from the Atlantic. Today, the water masses flowing into the

Caribbean over these sills are upper NADW (uNADW), which originates at depths of -1400 -

-3500 m and AAIW, which originates at depths of 800-1400 m (Haddad, 1994; Haddad and

Droxler, 1996). These two water masses mix together upon entering and fill the lower reaches of

the Caribbean basins as a result of turbulent mixing. Roth (1998) showed that water

temperatures below the sill depths in the Caribbean are distinct from waters of the same depth in

the Atlantic. Specifically, waters within the Caribbean basin are warmer and more

homogeneous. These temperatures indicate that the deep waters filling the Caribbean basins

have an origin shallower than 1500 m (Roth, 1998).

2.7 Ocean Circulation Models

Flow of Pacific water through an open CAS into the Atlantic was the result of several

general ocean circulation models evaluating the effects of shoaling of the Isthmus of Panama,









NADW production, and the location of the ITCZ (e.g., Mikolajewicz and Crowley, 1997;

Nisancioglu et al., 2003; Nof and van Gorder, 2003; Prange and Schultz, 2004; Klocker et al.,

2005; Schneider and Schmittner, 2006; Steph et al., 2006). Model results of Schneider and

Schmittner (2006) showed that when the isthmus shoaled to 2000 m the deep waters flowed from

the Atlantic to the Pacific, while the intermediate (>800 m) and surface waters flowed from the

Pacific to the Atlantic. The model presented by Nisancioglu et al. (2003) indicated that Pacific

intermediate waters began to flow through the CAS once the Isthmus of Panama shoaled to 1000

meters as a result of steric sea level differences between the Pacific and Atlantic. The production

of NADW affected the model results of Nof and Van Gorder (2003). Their results showed that

the net transport of water through the CAS would be westward without the formation of NADW,

while a high rate of NADW production would lead to eastward flow through the CAS. In the

model presented by Steph et al. (2006), the majority of the flow through the CAS was again from

the Pacific to the Atlantic as a result of steric sea level differences, with the exception of the

Ekman-dominated surface layer. This surface layer is affected when the ITCZ is located in its

southernmost location and the northeast trade winds profoundly effect steric sea level differences

in the gateway region diminishing the effects at the surface (Steph et al., 2006).

2.8 Description of Sample Sites

2.8.1 ODP Site 846B

Site 846B (3o5.696'S, 90049.078'W; 3296 m water depth) is located within the Peru

Basin (Figure 1-1). Coring recovered a continuous record of the early/middle Miocene boundary

at this site (Mayer, Pisias, Janecek, et al., 1992). The total depth of penetration of hole 846B was

422.4 mbsf (meters below seafloor), which corresponds to an age of -16 Ma (Mayer, Pisias,

Janecek, et al., 1992). The samples used in this study came from 272.3 to 371.5 mbsf, which

corresponds to an age range of 8.1 to 14.1 Ma. From 272.3 to 317 mbsf (8.1 to 10.8 Ma) the









samples are composed of clayey radiolarian diatom ooze interbedded with minor diatom

nannofossil ooze (Mayer, Pisias, Janecek, et al., 1992). From 317 to 371.5 mbsf (10.8 to 14.1

Ma) the sediments are composed of nannofossil ooze with minor amounts of biogenic silica

(Mayer, Pisias, Janecek, et al., 1992).

From 14.1 to 11.5 Ma the carbonate MARs ranged from 0.66 to 1.43 g/cm2 per k.y. (Figure

2-2) (Farrell et al., 1995) with an average value of -0.9 g/cm2 per k.y. After 11.5 Ma the

carbonate MARs decrease to levels ranging in values between 0.73 and 0.04 g/cm2 per k.y. until

8 My, with the exception of a spike to -1.24 g/cm2 per k.y. at 10.7 Ma (Farrell et al., 1995).

2.8.2 ODP Site 998A

Site 998A (19029.377'N, 82056.166'W; 3101 m water depth) is located on the northern

flank of the Cayman Rise in the Yucatan Basin (Figure 1-1). A continuous Cenozoic section was

recovered recording the evolution of Caribbean ocean circulation (Sigurdsson, Leckie, Acton, et

al., 1997). The total depth of penetration of hole 998A was 637.6 mbsf (50 Ma) (Sigurdsson,

Leckie, Acton, et al., 1997). The samples used in this study came from 132.5 to 177.7 mbsf,

which corresponds to an age range of 9 to 14 Ma. From 132.5 to 161 mbsf (9 to 12.1 Ma) the

samples are composed of nannofossil ooze with clay and nannofossil mixed sediments, and from

161 to 177.7 mbsf (12.1 to 14 Ma) they are composed of clayey nannofossil chalk and

nannofossil mixed sediment (Sigurdsson, Leckie, Acton, et al., 1997).

The carbonate MARs ranged between 0.54 and 0.86 g/cm2 per k.y. with an average of

-0.75 g/cm2 per k.y. (Figure 2-2) (Roth, 1998). From 12 to 10 Ma the values ranged between 0

and 0.7 g/cm2 per k.y. with lows from 12-11.8, 11.6-11.4, 11-10.8, 10.6-10.5, and 10.2 Ma

(Roth, 1998). After 10 Ma, the values return to an average of -0.75 g/cm2 per k.y. (Roth, 1998).









2.8.3 ODP Site 999A

Site 999A (12044.639'N, 78044.360'W; 2839 m water depth) is located on the Kogi Rise

within the Colombian Basin (Figure 1-1; Sigurdsson, Leckie, Acton, et al., 1997). This site was

selected in the hopes of recovering a continuous core that recorded the progressive closure of the

Central American Seaway (Sigurdsson, Leckie, Acton, et al., 1997). A total of 566.1 m of core

was recovered from site 999A (Sigurdsson, Leckie, Acton, et al., 1997), which correlates to an

age of -22.3 Ma (Peters et al., 2000). The samples used in this study came from 243.9 to 351.4

mbsf, which corresponds to 8.8 to 14 Ma. From 243.9 to 346.9 mbsf (8.8 to 13.8 Ma), the

samples are composed of indurated clayey nannofossil to clay with nannofossils, and from 346.9

to 351.4 mbsf (13.8 to 14 Ma) they are composed of clayey calcareous chalk with foraminifers

(Sigurdsson, Leckie, Acton, et al., 1997).

Carbonate MARs gradually decrease from -2 g/cm2 per k.y. to ~1 g/cm2 per k.y. from

14.2 to -12.1 Ma with significant decreases to values <0.5 g/cm2 per k.y. at 13.55, 13.05, and

12.55 Ma (Figure 2-2) (Roth, 1998). The largest decreases in carbonate MARs occurred

between 12 and 10 Ma with values ranging between 0 and 1 g/cm2 per k.y., with lowest

accumulations occurring at 12.0-11.8, 11.6-11.4, 11.0-10.8, 10.6-10.5, and 10.2 Ma (Roth,

1998). Carbonate MAR values increased from -1 to -1.5 g/cm2 per k.y. from 10 to 9 Ma (Roth,

1998).

2.8.4 Age Models

The age/depth model used for site 846B (Figure 2-3) is based on nannofossil

biostratigraphy of Raffi and Flores (1995) in which they used zonal boundaries defined by

Martini (1971) and Bukry (1973). The ages of these zonal boundaries and magnetic reversals

(Mayer, Pisias, Janecek, et al., 1992) were recalibrated to ages determined by Shackleton et al.

(1995a) using orbital tuning. The age/depth models for sites 998 and 999 were based on the









same zonal boundaries of Raffi and Flores (1995) and the recalibrated ages of Shackleton et al.

(1995a) by Kameo and Bralower (2000). Therefore the age models for all three sites were done

using the same age/depth models. Shackleton et al. (1995b) determined that the age uncertainty

of the nannofossils was +0.1 Ma.














































Simplified reconstruction of the Caribbean Region illustrating the locations of
sites 998 and 999 from this study (after Pindell (1994) and modified from Roth et
al. (2000).


Figure 2-1.

















2.0

1.5 <

1.0
0.5 U

0.0


8 9 10 11 12 13 14
Age (Ma)


Carbonate MAR records for sites 846, 998 and 999 from 8 to 14 Ma from Roth et
al. (2000)


<1.5
C 1.0
0
O 0.5
CU
o


< 1.5

c 1.0
0
O
0 0.5
(0


Figure 2-2.









CHAPTER 3
METHODS

3.1 Fossil Fish Teeth Sample Preparation

Sediment samples were oven dried, disaggregated and wet sieved prior to picking fossil

fish teeth from the >125 [tm fraction. The fossil fish teeth were then cleaned using an

oxidative/reductive cleaning technique from Boyle (1981) and Boyle and Keigwin (1985). The

oxidative/reductive cleaning technique removed organic matter and oxide coatings, which allows

for the analysis of isotopic ratios that are purely from the teeth. The cleaned teeth were dissolved

in aqua regia to remove additional organic material and then dried prior to the chemical

separation of Nd. Concentrations of Nd in the teeth typically range from 100 to 400 ppm (Martin

and Haley, 2000), and -100 |tg of cleaned teeth were used for analyses.

3.2 Column Chemistry

Effective isolation of Nd is a two step process. The first set of quartz columns, or primary

columns, isolate the bulk rare earth elements (REEs) from the sample using Mitsubishi cation

exchange resin with HC1 as the eluent. The dissolved teeth were dried and re-dissolved in 50 [iL

of 0.75 N HC1 and the REEs were eluted using 4.5 N HC1 after the removal of Ca, Sr, and Ba

using a standard procedure (Scher and Martin, 2004). After collection, the bulk REE samples

were again dried and re-dissolved with 200 iL of 0.18 N HC1 and passed through quartz

columns packed with Teflon beads coated with bis-ethylhexyl phosphoric acid, to separate Nd

and Sm from the other REE.

3.3 Nd Analysis

Nd isotopic ratios of the fossil fish teeth samples were analyzed using a Nu Plasma Multi-

Collector-Inductively Coupled Plasma-Mass Spectrometer (MC-ICP-MS) at the University of

Florida. Dried samples were re-dissolved with 0.3 mL of 2% optima HNO3, then 0.01 mL of the









sample was pipetted into a Teflon sampling beaker and diluted with 0.99 mL of 2% optima

HNO3. Additional acid or sample was added as needed to achieve the ideal voltage range of 2-6

volts for 143Nd. Belshaw et al. (1998) describe the instrument and the optimal operating

conditions for the Nu-MC-ICP-MS. JNdi-1 standard was run 5 to 10 times each day, depending

on the number of analyses acquired. A daily average for the standard was calculated for each

run, and the samples for that run were corrected to the long-term running average of the JNdi-1

standard from the TIMS, which has a 143Nd/144Nd of 0.512102 (+0.000012, 20). A drift

correction was not necessary because variations throughout a run did not indicate a consistent

drift. The 2c error varied on a daily basis, but the long-term 2c error is 0.35 ENd units.









CHAPTER 4
RESULTS

4.1 Neodymium Isotopic Ratios

The total range in ENd values at site 846 (Peru Basin) is from -3.75 to -1.65 (Figure 4-1,

Table 4-1). In the oldest part of the record at 14.1 Ma, ENd begins at -3.75 and slowly shifts to

more radiogenic ENd values up core (Figure 4-2). From 14.1 to 12.4 Ma the ENd values increase to

-2.3. From 12.4 to 12.0 Ma ENd values shift to less radiogenic values of -3.07. The ENd values

increase to --2.0 at 12.0 Ma and generally remain near that value until 8.4 Ma with a brief shift

to -2.93 at 10.6 Ma. After 8.4 Ma ENd decreases to -2.9 at 8.1 Ma. The range in ENd values at site

846 (Peru Basin) is much smaller than the Caribbean sites.

The total range for ENd values over the interval of interest at site 998 (Yucatan Basin) is

from -6.6 to 0 (Figure 4-1,Table 4-2). The ENd values remain relatively constant -4.0 from 14.1

to 12.2 Ma (Figure 4-2). From 12.2 to 10.1 Ma the ENd values become more variable, ranging

from -5.6 to 0 with a minimum baseline that decreases from -4 to -5.6. From 10.1 to 9.0 Ma ENd

values slowly decrease to a value of --6.6.

The total range of ENd values for site 999 (Colombian Basin) is from -6.4 to -0.1 (Figure 4-

1, Table 4-3). From 14.0 Ma to 13.7 Ma the ENd values increase from -5.5 to -3.1 (Figure 4-2).

Values remain around --3.0 from 13.7 to 12.1 Ma. At 12.0 Ma there is one point with a non

radiogenic value of -6.4. After this, the ENd values become more variable. From 12.0 to 10.6 Ma

the ENd values range from -3.0 to -0.1, and from 10.6 to 10.2 Ma values demonstrate a smaller

range of variability range from -3.0 to -4.4. The ENd values shift to more radiogenic values of

--2.0 from 10.2 to 9.4 Ma, and then decrease to -6.0 from 9.4 to 9.1 Ma. The final point at 9.0

Ma increases to -4.8.









4.2 ENd Compared to Carbonate MAR

The records for site 998 and 999 have been broken down into five intervals (pre-crash,

pre-crash transition, crash, post-crash transition, and post-crash) based on the ENd and the

carbonate MAR records (Figure 4-2). During the pre-crash interval at site 998 (>13.5 Ma), the

carbonate MAR and the ENd signals are relatively steady with ENd values around -4 and

carbonate MAR around -0.75. At site 999, ENd values become more radiogenic, shifting from

-5.5 to -3.1 during the pre-crash interval (>13.5 Ma), while the carbonate MAR decreases from

-2 to 1.25 g/cm2 per k.y.

During the pre-crash transition interval (13.5 12 Ma), the ENd values at sites 998 and 999

are relatively stable with values ranging between -4.3 to -3.5 and -3.7 to -2.4 respectively. The

carbonate MARs at site 999 range from 0 to 1.5 g/cm2 per k.y. and are more variable during the

pre-crash transition, while, those at site 998 are relatively constant at -1.25 g/cm2 per k.y.

During the crash interval (12-10 Ma) the ENd values are much more variable with values

ranging from -3.9 to 0 at site 998, and from -4.4 to -0.1 at site 999. The carbonate MARs at both

sites are highly variable with values as low as ~0 and as high as -1.3 g/cm2 per k.y. There is a

general negative correlation between low carbonate MAR and radiogenic ENd values at both sites

during the crash interval.

The post-crash transition and post-crash intervals are marked by increased carbonate MAR

with values around -1.0 at both sites. At site 998, the ENd values decrease from --5.5 to -6 over

the combined sections. At Site 999, the ENd values increase to -2 during the post-crash transition

interval, then decrease to -6 during the post crash interval.

At site 846, low carbonate MAR occurs later than in the Caribbean basin, and the record

has been divided into just two intervals (pre-crash and crash) because the post-crash recovery









was not recorded by this dataset and smaller subdivisions are not warranted. During the pre-

crash interval (14.14 to 11.2 Ma), the ENd values begin at -3.8 and increase to more radiogenic

values around --2, while carbonate MARs are -0.5 to 1.0 (Figure 4-2). During the crash interval

(11.2 to 8.1 Ma) carbonate MARs are ~0 to 0.5 and SNd values remain relatively stable ranging

between --1.7 and -2.3 with a short shift to -2.93 at 10.6 Ma and a decrease to -2.9 at 8.09 Ma,

which correlates with a brief increase in carbonate MAR. Site 846 also shows a general negative

correlation between low carbonate MAR and radiogenic ENd values during the carbonate crash

interval, similar to the correlation observed at sites 998 and 999.


















0-

-1 -

2-

z -3-
-4-

5-


-7



0

-1

-2

S-3
Z
-4

-5

-6

-7



0

-1

-2

z -3
Z
-4

-5

-6

-7


135 140 145 150 155 160 165 170 175 180

Depth (mbsf)



Figure 4-1. ENd values from site 846 in the eastern equatorial Pacific, sites 999 and 998 in the

Caribbean Basin plotted versus depth.


-6 -0-- Site 846


270 280 290 300 310 320 330 340 350 360 370


2*2 Site 999 3

- fh ^




- ^1'


250 260 270 280 290 300


310 320 330 340 350













Z0
C


ENd values and carbonate MARs from site 846 in the eastern equatorial Pacific
and sites 999 and 998 in the Caribbean Basin spanning from 8 to 14.5 Ma.
Carbonate MARs for site 846 are from Farrell et al. (1995) and for sites 999 and
998 are from Roth et al. (2000). Based on carbonate MARs site 846 is divided
into two intervals, pre-crash and crash, and the two Caribbean sites are divided
into five intervals (pre-crash, pre-crash transition, crash, post-crash transition, and
post-crash).


-*- Site 846 1.5

1.0

0.5

0.0
Post-Crash Post-CCrash rash Pre-Crash 2.0
Transition
I ~ -98 1.5
Site 998 <
1.0
O
0.5 )

0.0 0
2.0

1.5

1.0

0.5

0.0
8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5 13.0 13.5 14.0 14.5
Age (Ma)


Figure 4-2.










Table 4-1. Nd isotopes of Fossil Fish Teeth from ODP Site 846.


Sample Depth (mbsf) Age (Ma)


846B-29X-6W 61-67
846B-30X-3W 110-116
846B-31X-1W 77-83
846B-31X-2W 101-107
846B-31X-4W 98-104
846B-31X-6W 101-107
846B-32X-4W 103-109
846B-32X-6W 27-33
846B-32X-6W 94-100
846B-33X-1W 100-107
846B-33X-2W 31-37
846B-33X-4W 144-150
846B-33X-6W 30-36
846B-34X-1W 140-146
846B-34X-3W 121-127
846B-34X-4W 111-117
846B-34X-7W 21-27
846B-36X-2W 128-134
846B-36X-3W 128-134
846B-37X-2W 93-99
846B-38X-4W 144-150
846B-40X-1W 121-127


272.34
278.03
284.30
286.04
289.02
292.04
298.66
300.90
301.57
303.84
304.64
308.78
310.63
313.83
316.64
318.04
321.64
334.51
336.01
343.76
356.98
371.54


8.09
8.43
8.81
8.92
9.10
9.29
9.69
9.82
9.86
10.00
10.05
10.30
10.42
10.61
10.78
10.87
11.09
11.87
11.96
12.43
13.23
14.14


143Nd/144Nd
0.512488
0.512549
0.512547
0.512523
0.512535
0.512529
0.512534
0.512530
0.512532
0.512554
0.512526
0.512527
0.512510
0.512488
0.512526
0.512521
0.512541
0.512491
0.512481
0.512519
0.512490
0.512446


SNd(o)
-2.93
-1.75
-1.78
-2.25
-2.02
-2.27
-2.04
-2.12
-2.08
-1.65
-2.19
-2.17
-2.51
-2.93
-2.18
-2.28
-1.90
-2.88
-3.07
-2.33
-2.90
-3.75


20
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35










Table 4-2. Nd isotopes of Fossil Fish Teeth from ODP Site 998.


Sample
998A-15H-1W 21-26
998A-15H-3W 107-113
998A-15H-5W 27-32
998A-16H-1W 54-59
998A-16H-3W 126-129
998A-16H-4W 32-37
998A-16H-4W 45-50
998A-16H-5W 25.5-30
998A-16H-6W 32-36
998A-16H-6W 125-130
998A-17H-1W 21-26
998A-17H-1W 32-37
998A-17H-1W 77-82
998A-17H-1W 105-110
998A-17H-2W 25-30
998A-17H-2W 54-60
998A-17H-2W 126-131
998A-17H-4W 55-60
998A-17H-5W 2-7
998A-17H-5W 134-139
998A-17H-6W 26-31
998A-17H-6W 81-87
998A-17H-CCW 2-7
998A-18X-1W 105-111
998A-18X-3W 32-36
998A-19X-1W 53-58
998A-19X-5W 24-28
998A-20X-2W 32-36


Depth (mbsf)
132.51
136.37
138.58
141.85
146.05
146.62
146.77
148.11
149.65
150.58
151.53
151.62
152.08
152.35
153.05
153.36
154.06
156.38
157.38
158.68
159.09
159.65
160.62
161.85
164.12
166.75
172.44
177.72


Age (Ma)
8.95
9.33
9.52
9.79
10.14
10.18
10.19
10.30
10.46
10.59
10.73
10.75
10.82
10.86
10.97
11.02
11.13
11.50
11.66
11.82
11.87
11.93
12.03
12.17
12.41
12.70
13.50
14.05


143Nd/144Nd
0.512300
0.512323
0.512320
0.512379
0.512351
0.512396
0.512457
0.512378
0.512400
0.512491
0.512496
0.512545
0.512498
0.512466
0.512440
0.512476
0.512443
0.512574
0.512440
0.512491
0.512637
0.512594
0.512626
0.512420
0.512457
0.512418
0.512445
0.512434


8Nd(o)
-6.60
-6.15
-6.27
-5.06
-5.61
-4.73
-3.54
-5.08
-4.65
-2.88
-2.78
-1.82
-2.74
-3.36
-3.87
-3.17
-3.81
-1.26
-3.87
-2.88
-0.03
-0.87
-0.24
-4.26
-3.54
-4.30
-3.77
-3.99


20
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35











Table 4-3. Nd isotopes of Fossil Fish Teeth from ODP Site 999.


Sample
999A-28X-1W 18-23
999A-28X-3W 32-36
999A-28X-4W 84-88
999A-28X-5W 55-59
999A-29X-1W 72-76
999A-29X-2W 51-57
999A-29X-4W 25-29
999A-29X-6W 5-10
999A-29X-6W 66-70
999A-29X-6W 104-109
999A-30X-1W 128-132
999A-30X-2W 3-8
999A-30X-3W 59-63.5
999A-30X-4W 8-14
999A-30X-5W 2-7
999A-30X-6W 105-110
999A-30X-7W 28-33
999A-31X-2W 34-38
999A-31X-3W 7-12
999A-31X-4W 53-59
999A-32X-1W 28-33
999A-32X-2W 90-94
999A-32X-6W 18-23
999A-32X-6W 79-84
999A-33X-2W 4-10
999A-33X-3W 4-8
999A-33X-4W 106-111
999A-33X-6W 65-69
999A-33X-CCW 13-18
999A-34X-2W 145-150
999A-34X-3W 63-67
999A-34X-6W 100-105
999A-34X-6W 118-122
999A-35X-3W 109-113
999A-35X-5W 54-59
999A-35X-7W 17-21
999A-37X-1W 15-19
999A-37X-2W 6-11
999A-38X-1W 55-60
999A-38X-1W 69-73
999A-38X-5W 55-60


Depth (mbsf)
248.91
252.04
254.06
255.27
259.14
260.44
263.17
265.98
266.58
266.97
269.30
269.56
271.61
272.61
274.05
276.58
277.31
279.46
280.70
282.66
287.51
289.62
294.91
295.52
298.27
299.76
302.29
304.87
305.96
309.28
309.95
314.83
315.00
320.11
322.57
325.19
335.37
336.79
345.38
345.51
351.38


Age (Ma) 143Nd/144Nd
8.98 0.512395
9.10 0.512337
9.18 0.512360
9.22 0.512474
9.38 0.512546
9.52 0.512514
9.83 0.512555
10.15 0.512417
10.22 0.512489
10.26 0.512428
10.45 0.512415
10.46 0.512473
10.56 0.512421
10.61 0.512506
10.69 0.512495
10.78 0.512634
10.80 0.512508
10.87 0.512628
10.91 0.512506
10.98 0.512494
11.14 0.512547
11.21 0.512598
11.39 0.512580
11.41 0.512472
11.50 0.512568
11.55 0.512568
11.63 0.512470
11.72 0.512455
11.77 0.512501
12.01 0.512308
12.06 0.512486
12.41 0.512448
12.43 0.512447
12.80 0.512486
12.98 0.512503
13.17 0.512484
13.19 0.512513
13.42 0.512497
13.69 0.512470
13.70 0.512478
14.01 0.512359


8Nd(o)
-4.75
-5.88
-5.42
-3.21
-1.79
-2.43
-1.63
-4.31
-2.92
-4.09
-4.35
-3.22
-4.24
-2.58
-2.79
-0.07
-2.53
-0.19
-2.58
-2.80
-1.77
-0.78
-1.14
-3.25
-1.38
-1.37
-3.29
-3.56
-2.67
-6.44
-2.96
-3.70
-3.72
-2.96
-2.63
-3.00
-2.44
-2.76
-3.29
-3.12
-5.45


20
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35









CHAPTER 5
DISCUSSION

5.1 The Source of Caribbean Basin ENd Values in the Middle/Late Miocene

The ENd values within the Caribbean Basin extend to values that are more radiogenic than

any known intermediate/deep water masses within the equatorial Atlantic region. A critical

question is whether these values represent the true water mass signature or a diagenetic product.

An obvious source of radiogenic Nd is Caribbean arc volcanism. During the time interval of

this study, the Caribbean Basin was influenced by volcanic ash deposition with an ENd value of

-+7 (Drummond et al., 1995). Abundant layers and disseminated ash are observed at site 998

(Yucatan Basin) and site 999 (Colombian Basin) (Peters et al., 2000). However, a plot of the

low resolution ash MAR versus ENd for these sites illustrates that there is no correlation between

intervals of abundant ash and samples with more radiogenic ENd values (Figure 5-1). Another

possible diagenetic input would be sediment from the Magdalena and Orinoco Rivers in South

America that drain into the Caribbean Basin. The Magdalena River sediment has an ENd value of

-8.3 (Goldstein et al., 1984), while the Orinoco River sediment has an Nd value of --14

(Goldstein et al., 1997). Thus, these values are far too negative to have generated the radiogenic

ENd values observed in the Caribbean Basin.

Although the ENd values in the Caribbean are distinct from those in the Atlantic, they are

very similar to values recorded in the Pacific today and during the Miocene (Ling et al., 1997;

O'Nions et al., 1998; Frank et al., 1999; Reynolds et al., 1999; van de Flierdt et al., 2004).

Values for Pacific intermediate waters in the Miocene range from -3.6 to -4.0 from 9.2 to 13.4

Ma in the western equatorial Pacific (Fe-Mn crust D11-1, 1 139'N, 16141'E, 1,870-1,690m;

Ling et al., 1997), from 9.9 to 14.5 Ma in the central equatorial Pacific (Fe-Mn crust CD29-2,

16042'N, 16814'W, 2,390-1,970m; Ling et al., 1997), and from -2.0 to -2.6 from 8.8 to 13.13









Ma in the north Pacific (Fe-Mn crusts 13D-27A and D4-13A, Kamchatka and Alaska, 1,500 and

2,100 m; van de Flierdt et al., 2004) (Figure 5-2). The distribution of sNd in modern water

column profiles from the western north Pacific illustrates a similar range of values. Surface

waters from 3 m in this region have an ENd value of-0.1, while deep waters at 4,481 m have an

SNd value of -3.9 (Piepgras and Jacobsen, 1988). A second profile near a Fe-Mn crust studied by

van de Flierdt et al. (2004) documents a similar range of ENd values with +0.3 at 30 m and -4.5 at

2,800m (Piepgras and Jacobsen, 1988). van de Flierdt et al. (2004) concluded that in addition to

becoming less radiogenic with depth, the ENd values in the Pacific become more radiogenic at

progressively higher latitudes in the North Pacific.

The correlation between values recorded in the Caribbean and Pacific, plus associated

shifts in stable isotope data (Figures 5-3 and 5-4) support the idea that the ENd values in the

Caribbean Basin during the middle/late Miocene are dominated by a signature from the Pacific;

indicating that throughflow in the CAS was predominantly from west to east. Benthic 613C

values have been used as a proxy for deep ocean circulation based on the fact that 613C decrease

along the pathway of the global conveyor (i.e., Savin et al., 1981; Curry and Lohman, 1982;

Kroopnick, 1985; Woodruff and Savin, 1989; Broecker et al., 1990; Charles and Fairbanks,

1992); however, this proxy also responds to carbon cycling. Roth et al. (2000) showed that

middle to late Miocene 613C values shifted from 0.1 to 1.4%o in the Caribbean, and, like the ENd

values, the 613C values became more variable throughout the crash interval (Figure 5-3 and 5-4).

Charles and Fairbanks (1992) showed modem 613C values of intermediate water in the equatorial

Pacific fall within the range of <0%o to 0.8%o, while intermediate water in the equatorial Atlantic

have values >0.7%o; however, the distinction between the Pacific and Atlantic was more subtle

during the Miocene (Wright and Miller, 1996; Poore et al., 2006).









Nd isotopes provide a mechanism for deconvolving the circulation and nutrient signals

inherent in 613C. Piotrowski et al. (2005) used plots of sNd and 613C in the Southern Ocean to

illustrate that there are correlated shifts between the two systems, which they attributed to

changes driven by circulation and water mass composition on long-term and millennial

timescales. They also noted a lead/lag relationship during glacial terminations, indicating that

changes in 613C, and therefore the carbon mass balance of the ocean, preceded changes in

circulation as represented by SNd A similar comparison between ENd and 613C for the Caribbean

sites illustrates a general correlation between the two records, supporting the idea that the

variations in ENd record changes in circulation rather than ash diagenesis (Figures 5-3 and 5-4).

The radiogenic ENd values observed at sites 998 and 999 do not support the original

interpretation by Roth et al. (2000) that the waters filling the Caribbean during the middle to late

Miocene were derived from AAIW or NAIW. Instead, the ENd values are similar to Pacific

intermediate waters (Figure 5-2). This flow of Pacific water from west to east through the CAS

is also predicted by several general ocean circulation models evaluating the effects of an open

Isthmus of Panama (e.g., Mikolajewicz and Crowley, 1997; Nisancioglu et al., 2003; Nof and

Van Gorder, 2003; Prange and Schultz, 2004; Klocker et al., 2005; Schneider and Schmittner,

2006; Steph et al., 2006).

Based on benthic foraminiferal assemblages, Duque-Caro (1990) suggested that initial

uplift of the Isthmus of Panama to 2000 m occurred between 15.9 to 15.1 Ma (ages adjusted to

Shackleton et al., 1995a) and shoaling to -1000 m (upper bathyal depths) occurred between 12-

10.2 Ma (ages adjusted to Shackleton et al., 1995a). Shoaling of the Isthmus of Panama to 1000

m resulted in the flow of Pacific waters through the CAS into the Caribbean basin in the model

presented by Nisancioglu et al. (2003). The flow of Pacific water into the Caribbean Basin









agrees well with coccolith and planktonic foraminiferal assemblages (Chiasson and D'Hondt,

2000; Kameo and Sato, 2000) during this time. Site 999 (Caribbean Basin) and site 844 (eastern

equatorial Pacific) recorded identical assemblages from 16.2-13.6 Ma, these assemblages began

to diverge between 13.6-10.7 Ma, and finally completely distinct assemblages were identified

between 10.7-9.4 Ma (Kameo and Sato, 2000). Because coccoliths live within the photic zone,

the data suggest the CAS limited surface water exchange by -10 Ma.

Foraminiferal assemblages identified from site 999 also suggest the flow of Pacific water

into the Caribbean (Chiasson and D'Hondt, 2000). Chiasson and D'Hondt (2000) identified

temperate-latitude foraminiferal assemblages (Globoconellids) at site 999 until -10.7 Ma, and

interpreted their presence to represent an influx of cool Pacific surface water, either the

California or Peru Current system depending on the position of the ITCZ (Chiasson and

D'Hondt, 2000). Flohn (1981) predicts a more northerly position of the ITCZ at this time

(~10N) as a result of thermal asymmetry attributed to the differences in ice sheet development

between the northern and southern hemispheres. Due to the weaker pole-equator temperature

gradient in the northern hemisphere the ITCZ shifts to a more northern position, which Steph et

al. (2006) correlate to an increase in the eastward flow of Pacific waters into the Caribbean

Basin; a prediction that is consistent coccolith assemblages, foraminiferal assemblages, and SNd

records during this time.

5.2 Circulation during the Caribbean Pre-Crash and Pre-Crash Transition

During the pre-crash and pre-crash transition there are subtle differences between the ENd

values of the two Caribbean sites (Figure 4-2). Values at the southern site (site 999, Colombian

Basin) increase during the pre-crash interval and reach values more radiogenic than those at Site

998 during the pre-crash transition. This shift to more radiogenic ENd values at site 999 coincides

with a gradual shift to lower carbonate MARs, suggesting a progressive influx of more corrosive









and radiogenic intermediate Pacific waters through the CAS prior to the carbonate crash. The

SNd at site 998 remains relatively stable at a value similar to middle/late Miocene upper-

intermediate Pacific waters, but probably represent a mixture of Pacific and Atlantic surface

waters because the Nicaragua Rise acted as a barrier to intermediate and deep water flow into the

northern Caribbean Basin at this time.

Faulting of the Nicaragua Rise led to the opening of the north/south oriented Pedro

Channel and the northern part of the Walton Basin (Cunningham, 1998). These channels

provided a passage way for deep waters and ultimately led to the development of the Caribbean

Current, which flows from the southern Caribbean into the Gulf of Mexico across the region of

the Nicaragua Rise (Droxler et al., 1998). Prior to the connection between sites 998 and 999,

slight differences in ENd at the two sites suggest that intermediate waters from the Pacific

influenced site 999, while a mixture of Pacific and Atlantic surface waters influenced site 998

(Figure 5-5). Following the connection by -12 Ma (Droxler et al., 1998), the range of values

observed at sites 998 and 999 become more similar by -11.8 Ma, although there are still

distinctions between the two sites.

5.3 The Caribbean Carbonate Crash

At the beginning of the crash interval the ENd values at sites 998 and 999 diverge (Figure 5-

6) with the values from 12.1 to 11.8 Ma at site 998 representing surface waters from the Pacific

and the values at site 999 representing either deeper waters from the Pacific or, more likely, a

mixture of intermediate waters derived from the Pacific (NPIW) and Atlantic (AAIW) (Figures

4-2 and 5-2). During this time interval, site 998 still appears to be separated from the southern

Caribbean Basin by the Nicaragua Rise at an upper intermediate depth. The ENd values merge

from 11.8 to 11.5 Ma and again from 10.7 to 10.18 Ma implying a connection between the

northern and southern Caribbean sites that can be attributed to foundering of the Nicaragua Rise









(Droxler et al., 1992), which also lead to the initiation of the Loop Current in the Gulf of Mexico

(Mullins et al., 1987).

The history of the foundering of the Nicaragua Rise has important implications for deep

circulation in the Atlantic. Prior to the late early Miocene the Caribbean Current flowed through

the Havana/Matanzas Channel in western Cuba (Iturralde-Vincent et al.; 1996) into the Straits of

Florida, bypassing the Gulf of Mexico (Droxler et al., 1998). The Havana/Matanzas Channel

closed and the Pedro Channel opened during the late middle Miocene transition, redirecting the

Caribbean Current into the Gulf of Mexico, thereby initiating the Loop Current. This flow

pattern effectively increases the residence time of the water in a high evaporation region,

therefore the surface water exiting the Gulf of Mexico becomes more saline, leading to high

salinities in the Gulf Stream and ultimately in the surface waters of the North Atlantic. It is

estimated that the Loop Current was initiated -12-15 Ma (ages converted to Shackleton et al.,

1995a) in the middle Miocene (Mullins et al., 1987).

Throughout the carbonate crash interval (12-10 Ma) the carbonate MARs, 613C, and SNd

records show very erratic and large shifts at sites 998 and 999 with large decreases in carbonate

MARs associated with shifts to more radiogenic ENd values. These large shifts may represent

pulses of increased Pacific water inflow during carbonate dissolution events, while a greater

proportion of Atlantic inflow occurred during the intervals with less radiogenic ENd values and

enhanced carbonate preservation. The periods of increased Pacific inflow can also be linked to

times of increased production of NCW (Figure 5-7 and 5-8). The interval of the carbonate crash,

as defined by low carbonate MARs in the Caribbean Basin, correlates well with periods of

increased NCW production from -12.4 to 9.5 Ma as determined using 613C gradients between

the Atlantic and Pacific. During times of NCW production 613C values in the North Atlantic are









higher those in the Pacific. In contrast, there is very little difference between Atlantic and

Pacific 613C values when the Southern Ocean is the dominant source of deep water (Woodruff

and Savin,1989; Wright and Miller, 1996; Poore et al., 2006; ages calibrated to Shackleton et al.,

1995a). Based on interbasin 613C gradients, Woodruff and Savin (1989) argued for early, weak

production of NCW from 14.5 to 11.4 Ma (ages updated to Shackleton et al., 1995a). After this

time they proposed that strong SCW production dominated the deep Pacific and Atlantic in

response to growth of the Antarctic ice cap. The 11.4 Ma age (updated to Shackleton et al.,

1995a) coincides with the "silica switch" (Keller and Barron, 1983) when the primary site of

siliceous ooze deposition shifted from the Atlantic to the North Pacific and Indian Oceans, which

Woodruff and Savin (1989) attributed to increased NCW production Most studies agree that

early NCW was produced during parts of the late middle Miocene, but the highest production of

NCW in the Miocene occurred during the late Miocene (Blanc et al., 1980; Schnitker, 1980;

Miller and Fairbanks, 1985; Woodruff and Savin, 1989; Wright et al., 1991, 1992, and 1996;

Wei, 1995; Wei and Peleo-Alampay, 1997).

Thomas and Via (2007) developed a Neogene Nd isotopic record at Walvis Ridge in the

southeastern Atlantic Ocean to evaluate the onset of NCW production. The ENd values at site

1262 begin to decrease at -13 Ma with a major decrease beginning at -10.6 Ma. Thomas and

Via (2007) interpret this shift to indicate greater proportions of NCW in the southeastern Atlantic

Ocean. They argue that the carbonate crash in the Caribbean and equatorial Pacific was the

result of the onset of deep water formation in the Labrador Sea. The offset in the timing of the

carbonate crash and the timing of the decrease in ENd values was probably a result of a low

resolution ENd record (Thomas and Via, 2007). In the Caribbean, the Nd isotopic record agrees









with enhanced NCW production determined by Wright and Miller (1996) and Poore et al. (2006)

in which they suggested was controlled by the flow over North Atlantic sills

Wright and Miller (1996) used 613C gradients between the Atlantic, Pacific and Southern

Ocean to calculate the %NCW production. Poore et al. (2006) updated the %NCW production

calculations using new data and found that increased NCW production occurred at -12 Ma,

which is similar to the results Wright and Miller (1996) that suggest an increase at -12.5 Ma. A

comparison between this calculated %NCW production and the ENd record for Site 998 and 999

illustrates that, in general, increased production of NCW correlates with more radiogenic ENd

values and decreased carbonate MARs (Figure 5-7 and 5-8). In other words, the carbonate crash

events occur during times of enhanced NCW production.

The overall correlation between increased SNd values and decreased carbonate MARs can

therefore be attributed to the flow of corrosive intermediate and surface Pacific waters through

the CAS into the Caribbean Basin during times of enhanced NCW production. This water would

then flow north across the shallow Nicaragua Rise, ultimately filling both basins (Colombian and

Yucatan) with corrosive waters with radiogenic Nd isotopes.

The one exception to this correlation occurs at -12 Ma at Site 999 when increased NCW

production and decreased carbonate MARs coincides with less radiogenic ENd values. One

possible explanation is that these less radiogenic ENd values during this early carbonate crash

interval represent AAIW that flowed into the southern Caribbean basin when NCW production

rates were high. Thus, the southern basin was filled with a mixture of corrosive AAIW and

NPIW, with AAIW dominating at -12 Ma, while the northern basin was filled with

shallow/intermediate Pacific water (Figure 5-9). This idea is similar to the theory presented by

Roth et al. (2000) that increased NCW was compensated by reduced NAIW and, therefore, more









corrosive AAIW overflowed the sills and filled the Caribbean Basin. As mentioned previously,

the northern site (998) was still separated from the southern Caribbean by the Nicaragua Rise;

therefore, this site records shallow/intermediate Pacific throughflow observed in subsequent

crash intervals instead of the deeper NAIW/AAIW mix.

5.4 Circulation during the Caribbean Post-Crash Transition and Post-Crash

The ENd values at sites 998 and 999 diverge during the post-crash transition. Site 999

records a brief excursion to more radiogenic ENd values from 9.8 to 9.4 Ma, while site 998

continues to shift to less radiogenic values. The timing of these events correlates with a decrease

in NCW production (Wright and Miller, 1996; Poore et al., 2006) (Figures 5-7 and 5-8), and a

shift to light 613C after the Caribbean carbonate MAR recovered (Figures 5-3 and 5-4). The brief

excursion at site 999 records more Pacific-like values, while Site 998 continues to record an

Atlantic/Pacific value with a decreasing Pacific component (Figure 5-10). The lack of a

dissolution event associated with radiogenic ENd values at site 999 could have been the result of

increased productivity and an associated increase in the carbonate rain rate in response to an

increase in nutrient levels supplied from old, Pacific waters. The 613C values recorded at site

999 (Roth, 1998) supports with this interpretation because the values become lighter, indicating a

more nutrient-rich water mass filling the southern Caribbean Basin (Figure 5-4). The fact that

site 998 ENd values decrease while site 999 ENd values increase also supports the idea that at least

part of the 613C signal is a response to productivity rather than water mass. An alternative

scenario is that the entire Caribbean was filled with more Atlantic sourced water (i.e. NAIW) as

a result of the decreasing production of NCW, but site 999 continued to record more radiogenic

ENd values because of its proximal location to the CAS. The mixture of upper NPIW, Pacific

surface waters, and NAIW at this site would account for the combination of enhanced carbonate

preservation and more radiogenic ENd values. The continual decrease in ENd values at site 998









during this time suggests that the mixture observed at site 999 combined with a progressively

increasing fraction of Atlantic waters before circulating into the northern basin.

Gradually decreasing ENd values during the post-crash transition and post-crash at site 998

and post-crash at site 999 highlight the gradual reduction of Pacific throughflow coincident with

the shoaling of the Isthmus of Panama and the foundering of the Nicaragua Rise. Frank et al.

(1999) and Reynolds et al. (1999) proposed a decrease in Pacific throughflow entering the

Florida Straits via the Loop Current beginning at -8.5 Ma based on data from Fe-Mn crusts in

the equatorial Pacific and Florida Straits. Data from sites 998 and 999 illustrate that decreasing

throughflow began at -10.7 Ma. It is impossible to determine whether the Atlantic source at this

time was NAIW or AAIW because the percentage of Pacific versus Atlantic inflow is unknown.

5.5 The Pacific Carbonate Crash

Shoaling of the Isthmus of Panama and the subsequent production of NCW also affected

circulation patterns in the Pacific Ocean and contributed to the middle Miocene carbonate crash

in the eastern equatorial Pacific, although this event at site 846 lags the crash in the Caribbean

Basin. The idea is that enhanced NCW production resulted in a greater contribution of NCW to

Circumpolar Water (CPW), thereby lengthening the pathway of deep water entering the Pacific

and resulting in older, more corrosive deep waters. In today's ocean much of the Pacific deep

water flows southward as either NPIW or PCW (Mix, Tiedemann, Blum, et al., 2003; Figure 5-

11). The formation of NPIW occurs with relatively little interaction with the atmosphere,

causing the water mass to remain depleted in oxygen, high in CO2 (Talley, 1993), and have the

highest nutrient concentration in the Pacific (Figure 5-11). Enhanced global conveyor

circulation associated with NCW production would therefore result in more corrosive NPIW,

PCW, and North Pacific Surface and increased flow of that water toward the south.









The ENd shift toward slightly more radiogenic values during the carbonate crash interval

at site 846 (Figure 4-2) supports this link between NCW production and the composition of

Pacific waters. More radiogenic ENd values and decreased carbonate MAR's would both result

from the expansion of corrosive NPIW and PCW southward in response to NCW production.

The timing of dissolution events recorded at sites in the eastern equatorial Pacific documents the

development and introduction of this more corrosive water mass from the north. The most

northerly site examined in the eastern equatorial Pacific (Leg 138 site 845; 3,715 m) experienced

a large decrease in carbonate MARs beginning at approximately 12 Ma. Carbonate dissolution

also occurred between -12 to 9 Ma at an intermediate water depth site (Leg 202 site 1241 on the

Coccos Ridge; 2,027 m) at the same latitude as the CAS (Mix, Tiedemann, Blum, et al., 2003).

Sites 844 (3,415 m) and 846 (3,307 m) on the other hand, which are further south than site 845,

did not begin to experience carbonate dissolution until -11.5 Ma. Thus, the introduction of

corrosive waters coming from the north Pacific progressed from the more northerly sites to more

southerly sites.

The carbonate MAR and SNd records for site 846 suggest that this site does not represent

the endmember of the intermediate depth water flowing into the Caribbean Basin. Instead, it

monitors the water mass that flowed south of the CAS into the Peru Basin. On the other hand,

site 1241 located on the Coccos Ridge across from the CAS in the Pacific at intermediate depth

might be a better site to monitor the Pacific intermediate depth throughflow because of its

location and depth.














0.6



0.4 0Q

,-c
U,
0.2



0.0


8 9 10 11 12 13 14


0.6



0.4 I

-c
0,
0.2



0.0


8 9 10 11 12 13 14

Age (Ma)


ENd values and ash MARs (Peters et al., 2000)
Caribbean Basin spanning from 8 to 14.5 Ma.


from sites 999 and 998 in the


Figure 5-1.











0


-2


-4


-6


-8


-10


-12


0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Age (Ma)


ENd values from sites 998 and 999 in the Caribbean Basin, site 846 in the eastern
equatorial Pacific, Fe-Mn crusts from the North Atlantic, Straits of Florida, North
Pacific, central equatorial Pacific (Burton et al., 1997, 1999 (BM1969.05);
O'Nions et al., 1998 (ALV 539)), Straits of Florida (Reynolds et al., 1999
(BM1963.897)), North Pacific (van de Flierdt et al., 2004 (D4-13A, 13D-27A)),
central equatorial Pacific (Ling et al., 1997 (VA13-2, CD29-2, D 1-1); Frank et
al., 1999 (GMAT 14D)). ENd values from sites 998 and 999 are very similar to
Pacific values from 14 to -10 Ma. Following the carbonate crash they approach
values recorded at BM1963.897 in the Straits of Florida.


Figure 5-2.











0.0


0.2


0.4


0.6
0
CO
o 0.8


1.0


1.2


1.4


9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5 13.0 13.5 14.0


Age (Ma)


ENd and 613C values (Roth, 1998) from site 998.


Figure 5-3.














0


-1


-2


-3 z


-4


-5


-6


10 11 12

Age (Ma)


ENd and 613C values (Roth, 1998) from site 999.


Figure 5-4.













































Flow patterns of Atlantic (green) and Pacific (blue) waters during the Pre-
Crash/Pre-Crash Transition intervals. Solid lines represent flow of intermediate
water and dashed lines represent upper/surface flow. Simplified reconstruction of
the Caribbean Basin (after Pindell (1994) and modified from Roth et al. (2000)).


Figure 5-5.













-- Site 999 (Colombian Basin)
-- Site 998 (Yucatan Basin)


9 10 11 12 1 1
9 10 11 12 13 14


Age (Ma)


ENdvalues from sites 998 and 999 in the Caribbean Basin spanning from 8 to 14.5
Ma.


Figure 5-6.













100


80



Q
60 <


z C
0c
40-
C



20 -




0 -


Figure 5-


1.0



0.8



0.6

2

0.4



0.2



0.0


9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5 13.0 13.5 14.0


Age (Ma)


%NCW sN ~ ca3 MAR Site 998 Yucatan Basin


7. ENd values from site 998, carbonate MAR (Roth et al., 2000), and %NCW (Wright
and Miller, 1996).














100




80




60

CZ


40




20




0


Figure 5-8.


2.0





1.5






C)




0.5





0.0
9.0 9.5 10.0 10.5 11.0 11.5 1

Age (Ma)
SsNd CaCO3 MAR %NCW


ENd values from site 999, carbonate MAR (Roth et al., 2000), and %NCW (Wright
and Miller, 1996).


2.0 12.5 13.0 13.5 14.0



Site 999 Yucatan Basin













































Flow patterns of Atlantic (green) and Pacific (blue) waters during the Carbonate
Crash interval. Solid lines represent flow of intermediate water and dashed lines
represent upper/surface flow. Simplified reconstruction of the Caribbean Basin
(after Pindell (1994) and modified from Roth et al. (2000)).












59


Figure 5-9.













































Figure 5-10.


Flow patterns of Atlantic (green) and Pacific (blue) waters during the Post-Crash
Transition/Post-Crash intervals. Solid lines represent flow of intermediate water
and dashed lines represent upper/surface flow. Simplified reconstruction of the
Caribbean Basin (after Pindell (1994) and modified from Roth et al. (2000)).









Water entering the
Caribbean Basin
through the CAS


AAIW123
AA1W1233 4


e 1232 CPDW
hft4n 0


A
0


2


4


Bo

E
12


4
4


4.0 JP

2.0 a


10 0 10


,' 1235GUC P
AAIW 12 12



1232 CPDW 1237


3.0


ACL
1.0
-.


50 40 30 20 10


0 10


ai In- .i ..lf,


o PCW 12390
1236 1238.,
1240
01


'1242
o 1241 .


50 40 30 20
Latitude ()


Figure 5-11.


Dissolved oxygen profile from the Pacific (modified after Mix, Tiedemann, Blum,
et al., 2003). White box indicates the water mass which would flow through the
CAS after the Isthmus of Panama shoaled to 1000 m.


0 40 30 20


AAIW1233


Co

- 1
2
.3
4


12l3 "
1234


35.0

34.5 k

34.0

133.5


1


1232 QPDW
-- b-~


I









CHAPTER 6
CONCLUSIONS

Fossil fish teeth were analyzed from sites 998 and 999 in the Caribbean Basin and site 846

in the eastern equatorial Pacific to study ocean circulation using Nd isotopes during the middle to

late Miocene carbonate crash. The radiogenic ENd values recorded in the Caribbean Basin range

from 0 to -6.6 and are distinct from values reported in the Atlantic. The lack of correlation

between ENd and ash deposition in the Caribbean Basin and the close correlation to values

recorded in the Pacific during the Miocene argue that these radiogenic values represent CAS

throughflow rather than ash alteration. West to east flow through the CAS is consistent with

general ocean circulation models and 613C data.

In the Caribbean Basin, more radiogenic ENd values correlate with intervals of decreased

carbonate MARs. The gradual decrease in carbonate MARs and increase in ENd values beginning

at -14 Ma at site 999 indicates the gradual introduction of a more corrosive, intermediate water

mass flowing into the southern Caribbean Basin from the Pacific, while the northern Caribbean

Basin site (site 998) ENd values and carbonate MARs remained relatively stable with values

representing a mixture of Pacific and Atlantic surface waters. During the carbonate crash

interval (12-10 Ma) the ENd values are highly variable and peak at 0 ENd units, indicating pulses of

Pacific waters entering the Caribbean Basin. This inflow of Pacific waters into Caribbean Basin

through the CAS is predicted by several GCMs looking at the affects of CAS sill depths, NADW

production, and the location of the ITCZ.

Although sites 998 and 999 record similar ENd values there are distinct differences between

the two records that can be attributed to their locations relative to the CAS, as well as the extent

of communication across the Nicaragua Rise. After the carbonate crash, the ENd values in the

Caribbean gradually shift to less radiogenic values, indicating a gradual decline in the amount of









Pacific water entering the Caribbean Basin, coincident with the shoaling of the Isthmus of

Panama. The increased proportion of Atlantic waters in the water mass exiting the Caribbean

and flowing through the Straits of Florida is also documented by decreasing ENd values in an Fe-

Mn crust from the Straits of Florida (Reynolds et al., 1999).

Site 846 in the Pacific shows a similar pattern to the Caribbean Basin in which the ENd

values shift to more radiogenic values during times of decreased carbonate MARs. The initiation

of the Pacific carbonate crash appears to be the result of the continued shoaling of the Isthmus of

Panama and enhanced production of NCW. The increase in the ENd to more NPIW values, and

the southward progression of low carbonate MARs from sites 845 and 1251 to sites 844 and 846

farther south support the idea that older, more corrosive NPIW and PCW flowed southward in

the eastern equatorial Pacific, causing the carbonate crash in this region.

Wright and Miller (1996) and Poore et al. (2006) suggest increased NCW production was

the result of the subsidence of the Greenland-Scotland Ridge in the North Atlantic. These results

also indicate that increased NCW production coincides with shoaling of the Isthmus of Panama,

foundering of the Nicaragua Rise, and the carbonate crash in the Caribbean region. In the

Caribbean region, foundering of the Nicaragua Rise and the development of the Loop Current

increased the residence time of waters in the Gulf of Mexico resulting in more saline outflow to

the North Atlantic, further enhancing NCW production. In addition, enhanced production of

NCW affected the age of CDW flowing into the Pacific Ocean, resulting in more corrosive

NPIW and PCW returning southward, producing a north to south progression of carbonate

dissolution from the eastern equatorial Pacific region and Caribbean Basin to the southern

eastern equatorial Pacific region during the middle/late Miocene carbonate crash.









LIST OF REFERENCES


Abouchami W., Goldstein S.L.., Galer S.J.G., Eisenhauer A., and Mangini A. (1997)
Secular changes of lead and neodymium in central Pacific seawater recorded by
a Fe-Mn crust. Geochim. Cosmochim. Acta 61(18), 3957-3974.

Albarede F., and Goldstein S.L. (1992) World map of Nd isotopes in sea-floor
ferromanganese deposits. Geology 20, 761-763.

Albarede F., Goldstein S.L., and Dautel D. (1997) 143Nd/144Nd of Mn nodules from the
Southern Ocean and Indian oceans, the global oceanic Nd budget, and their
bearings on the deep ocean circulation during the Quaternary. Geochim.
Cosmochim. Acta 61, 1277-1291.

Austin J. A., Schlager W., Palmer A.A., and ODP Leg 101 Scientific Party. (1988)
Proceedings of the Ocean Drilling Program, Initial Reports (Part A). Ocean
Drilling Program, College Station, Texas.

Belshaw N. S., Freedman P.A.., O'Nions R.K.., Frank M., and Guo Y. (1998) A new
variable dispersion double-focusing plasma mass spectrometer with performance
illustrated for Pb isotopes. International Journal of Mass Spectrometry 181 51-
58.

Bertram C. J., and Elderfield H. (1993) The geochemical balance of the rare earth
elements and Nd isotopes in the oceans. Geochim. Cosmochim. Acta 57, 1957-
1986.

Bird D., Hall S. A., Casey J.F., and Millegan P.S. (1993) Interpretation of magnetic
anomalies over the Grenada Basin. Tectonics 12, 1267-1279.

Blanc P.-L.., Rabussier D., Vergnaud-Grazzini C., and Duplessy J.C. (1980) North
Atlantic Deep Water formed by the later middle Miocene. Nature 283, 553-555.

Boyle E. A. (1981) Cadmium, Zinc, Copper and Barium in foraminifera tests. Earth
Planet. Sci. Lett. 53, 11-35.

Boyle E. A., and Kiegwin L.D. (1985) Comparison of Atlantic and Pacific paleochemical
records for the past 215,000 y: Changes in deep ocean circulation and chemical
inventories. Earth Planet. Sci. Lett. 76, 135-150.

Broecker W.S., and Peng T.-H. (1982) Tracers in the Sea. Eldigio Press.

Broecker W. S., Bond G., Klaus M., Bonani G.A., and Wolfli W. (1990) A salt oscillator
in the glacial Atlantic? 1. The concept. Paleoceanography 5, 469-477.









Buckry D. (1973) Low-latitude coccolith biostratigraphic zonation. In: Edgar N.T.,
Saunders J.B., et al. (Ed.),lnit. Repts. DSDP 15. U.S. Govt. Printing Office,
Washington. 685-703

Burton K. W., Ling H.-F., and O'Nions R.K. (1997) Closure of the Central American
Isthmus and its effect on deep-water formation in the north Atlantic. Nature 386,
382-385.

Burton K.W., Lee D.-C., Christensen J.N., Halliday A.N., and Hein J.R. (1999) Actual
timing of neodymium isotopic variations recorded by Fe-Mn crusts in the western
North Atlantic. Earth Planet. Sci. Lett. 171, 149-156.

Charles C.D., and Fairbanks R.G. (1992) Evidence from Southern Ocean sediments for
the effect of North Atlantic deep-water flux on climate. Nature 355, 416-419.

Chiasson W.P., and D'Hondt S.L.. (2000) Neogene Planktonic Foraminifer
Biostratigraphy at Site 999, Western Caribbean Sea. In: Leckie, R. M.,
Siquardssom, H., Acton, G.D., and Draper, G. (Ed.),Proc. ODP, Sci. Res. 165.
Ocean Drilling Program, College Station, TX.

Coates A.G., Jackson J.B., Collins L.S., Cronin T.M., Dowsett H.J., Bybell L.M., Jung
P., and Obando J.A. (1992) Closure of the Isthmus of Panama: the near-shore
marine record of Costa Rica and Western Panama. Geol. Soc. Am. Bull. 104,
814-828.

Cunningham A. D. (1998) Neogene Evolution of the Pedro Channel Carbonate System,
Northern Nicaragua Rise [Ph.D. thesis], Rice University.

Curry W.B., and Lohmann G.P. (1982) Carbon isotopic changes in benthic foraminifera
from the western South Atlantic: Reconstruction of glacial abyssal circulation
patterns Quaternary Research 18, 218-235.

Denny W.M., Austin J.A., and Buffler R.T. (1994) Seismic stratigraphy and geologic
history of mid-Cretaceous through Cenozoic rocks, Southern Straits of Florida.
AAPG Bulletin 78, 461-487.

DePaolo D.J., and Wasserburg, G.J. (1976) Nd isotopic variations and petrogenetic
models. Geophys. Res. Lett. 3, 249-252.

Droxler A.W., Cunningham A.D., Hine A.C., Hallock P., Duncan D., Rosencrantz E.,
Buffler R., and Robinson E. (1992) Late Middle (?) Miocene segmentation of an
Eocene-early Miocene carbonate megabank on the northern Nicaragua Rise.
EOS, Transactions (supplement) 73.

Droxler A.W., Burke K.C., Cunningham A.D., Hine A.C., Rosencrantz E., Duncan D.S.,
Hallock P., and Robinson E. (1998) Caribbean constraints on circulation between









Atlantic and Pacific Oceans over the past 40 million years. In: Crowley, T. J., and
K.C. Burke (Ed.), Tectonic Boundary Conditions for Climate Reconstructions.
Oxford Univ. Press, New York.

Drummond M.S., Bordelon M., De Boer J.Z.., Defant M.J., Bellon H., and Feigenson
M.D. (1995) Igneous petrogenesis and tectonic setting of plutonic and volcanic
rocks of the Cordillera De Talamanca, Costa Rica-Panama, Central American
Arc. American Journal of Science 195, 875-919.

Duque-Caro H. (1990) Neogene stratigraphy, paleoceanography and
paleobiogeography in northwest South America and the evolution of the Panama
Seaway. Palaeogeogr., Palaeoclim., Palaeoecol. 77, 203-234.

Elderfield H., and Greaves M.J. (1982) The rare earth elements in seawater. Nature
296, 214-219.

Elderfield H., and Pagett R. (1986) Rare earth elements in icthyoliths: Variations with
redox conditions and depositional environments. Sci. Total Environ. 49, 175-197.

Elderfield H. (1988) The oceanic chemistry of the rare earth elements. Philos. Trans. R.
Soc. London Ser. A(325), 105-126.

Exon N., Kennett J.P., and Scientific Shipboard Party. (2002) Drilling reveals climatic
consequences of Tasmanian Gateway opening. EOS, Transactions AGU 83,
253-259.

Farrell J.D., Raffi I., Janecek T.R., Murray D.W., Levitan M., Dadey K.A., Emeis K.-C.,
Lyle M., Flores J. -A., and Hovan S. (1995) Late Neogene sedimentation
patterns in the eastern equatorial Pacific Ocean. In Proceeding ODP, Scientific
Results, Vol. 135 (ed. L. A. M. N.G. Pisias, and T.R. Janecek), pp. 717-756.

Frank M., and O'Nions R.K. (1998) Sources of Pb for the Indian Ocean ferromanganese
crusts: a record of Himalayan erosion? Earth Planet. Sci. Lett. 158, 121-130.

Flohn H. (1981) A hemispheric circulation assymetry during late Tertiary. Geol.
Rundsch. 70, 725-736.

Frank M., Reynolds B.C., and O'Nions R.K. (1999) Nd and Pb isotopes in Atlantic and
Pacific water masses before and after closure of the Panama gateway. Geology
27, 1147-1150.

Frank M., Whiteley N., Kasten S., Hein J.R., and O'Nions R.K. (2002) North Atlantic
Deep Water export to the Southern Ocean over the past 14 Myr: Evidence from
Nd and Pb isotopes in ferromanganese crusts. Paleoceanography
17(doi: 10.1029/2000PA000606).









Frank M. (2002) Radiogenic isotopes: tracers of past ocean circulation and erosional
input. Reviews in Geophysics 40, 1-38.

Frank M., van de Flierdt T., Halliday A.N., Kubik P.W., Hattendorf B., and Gunther D.
(2003) Evolution of deepwater mixing and weathering inputs in the central
Atlantic Ocean over the past 33 Myr. Paleoceanography 18.

German C.R., Klinkhammer G.P., Edmond J.M., Mitra A., and Elderfield H. (1990)
Hydrothermal scavenging of rare-earth elements in the ocean. Nature 345, 516-
518.

Goldstein S.L., O'nions R.K., and Hamilton P.J. (1984) A Sm-Nd isotopic study of
atmospheric dusts and particulates from major river systems. Earth Planet. Sci.
Lett. 70, 221-236.

Goldstein S.J., and Jacobsen S.B. (1988) Rare earth elements in river waters. Earth
Planet. Sci. Lett. 89, 35-47.

Goldstein S.L., Arndt N.T., and Stallard R.F. (1997) The history of a continent from U-Pb
ages of zircons from Orinoco River sand and Sm-Nd isotopes in Orinoco basin
river sediments. Chemical Geology 138, 271-186.

Goldstein S.L., and Hemming S.R. (2003) Long-lived isotopic tracers in oceanography,
paleoceanography and ice sheet dynamics. In Treatise on Geochemistry, Vol. 6
(ed. H. Elderfield), pp. 453-489. Elsevier.

Gomberg D. (1974) Geology of the Portales Terrace. Florida Science 37, 15.

Greaves M.J., Statham P.J., and Elderfield H. (1994) Rare earth element mobilization
from marine atmospheric dust into seawater. Marine Chemistry 46, 255-260.

Haddad G.A. (1994) Calcium carbonate dissolution patterns at intermediate water
depths of the Tropical oceans during the Quaternary [Ph.D. thesis], Rice
University.

Haddad G.A., and Droxler A.W. (1996) Metastable CaCO3 dissolution at intermediate
water depths of the Caribbean and western North Atlantic: Implications for
intermediate water circulation during the past 200,000 years. Paleoceanography
11, 701-716.

Haug G.H., and Tiedemann R. (1998) Effect of the formation of the Isthmus of Panama
on Atlantic Ocean thermohaline circulation. Nature 393, 673-676.

Henry F., Jeandel C., and Minster J, -F. (1994) Particulate and dissolved Nd in the
western Mediterranean Sea: Sources, fates and budget. Marine Chemistry 45,
283-305.










Iturralde-Vinent M., Hubbell G., and Rojas R. (1996) Catalogue of Cuban fossil
Elasmobranchii (Paleocene to Pliocene) and paleogeographic implications of
their Lower to Midddle Miocene occurrence. J. Geological Soc. Jamaica 31, 7-21.

Jeandel C. (1993) Concentration and isotopic compositions of Nd in the South Atlantic
Ocean. Earth Planet. Sci. Lett. 117, 581-591.

Jeandel C., Bishop J.K., and Zindler A. (1995) Exchange of Nd and its isotopes
between seawater small and large particles in the Sargasso Sea. Geochim.
Cosmochim. Acta 59, 535-547.

Jeandel C., Thouron D., and Fieux M. (1998) Concentrations and isotopic compositions
of neodymium in the eastern Indian Ocean and Indonesian Straits. Geochim.
Cosmochim. Acta 62, 2597-2607.

Johns W.E., Townsend T.L., Fratantoni D.M., and Wilson W.D. (2002) On the Atlantic
inflow to the Caribbean Sea. Deep-Sea Research I 49, 211-243.

Kameo K., and Bralower T.J. (2000) Neogene nannofossil biostratigraphy of Sites 998,
999, and 1000. In Proc. ODP, Sci. Res., Vol. 165 (ed. R. M. Leckie,
Siquardssom, H., Acton, G.D., and Draper, G.), pp. 3-18.

Kameo K., and Sato T. (2000) Biogeography of Neogene calcareous nannofossils in the
Caribbean and the eastern equatorial Pacific-floral response to the emergence of
the Isthmus of Panama. Marine Micropaleontology 39, 201-218.

Keigwin L.D. (1982) Isotopic Paleoceanography of the Caribbean and East Pacific:
Role of Panama Uplift in Late Neogene Time. Science 217, 350-353.

Keller G., and Barron J.A. (1983) Paleoceanographic implications of Miocene deep-sea
hiatuses. Geol. Soc. Am. Bull. 94, 590-613.

Keller G., Zenker C.E., and Stone S.M. (1989) Late Neogene history of the Pacific-
Caribbean gateway. Journal of South American Earth Science 2, 73-108.

Kennett J.P., Houtz R.E., Andrews P.B., Edwards A.R., Gostin V.A., Hajos M., Hampton
M.A., Jenkins D.G., Margolis S.V., Ovenshine A.T., and Perch-Nielsen K. (1974)
Development of the Circum-Antarctic Current. Science 18, 144-147.

Kennett J.P. (1977) Cenozoic evolution of Antarctic Glaciation, the Circum-Antarctic
Ocean and their impact on global paleoceanography. Journal of Geophysical
Research 82, 3843-3860.

King T.A., Ellis Jr. W.G., Murray D.W., Shackleton N.J., and Harris S. (1997)









Miocene evolution of carbonate sedimentation at the Ceara Rise: a multivariate
date/proxy approach. In Proc. ODP, Scientific Results, Vol. 154 (ed. N. J.
Shackleton, Curray, W.B., Richter, C., and Bralower, T.J.), pp. 349-366.

Klocker A., Prange M., and Schulz M. (2005) Testing the influence of the Central
American Seaway on orbitally forced Northern Hemisphere glaciation. Geophys.
Res. Lett. 32, L03703.

Kroopnick P. M. (1985) The distribution of 13C in the world oceans. Deep Sea Research
32, 57-84.

Lacan F., and Jeandel C. (2001) Tracing Papua New Guinea imprint on the central
Equatorial Pacific Ocean using neodymium isotopic compositions and Rare Earth
Element patterns. Earth Planet. Sci. Lett. 186, 497-512.

Le J., Mix A.C., and Shackleton N.J. (1995) Late Quaternary paleoceanography in the
eastern equatorial Pacific Ocean from planktonic foraminifers: a high-resolution
record from Site 846. In: Pisias, N. G., Mayer L.A., Janecek T.R., Palmer-Julson
A., and van Andel T.H. (Ed.),Proc. ODP Sci. Res. 138. Ocean Drilling Program,
College Station, TX.

Lewis J.F., and Draper G. (1990) Geology and tectonic evolution of the northern
Caribbean margin. In: Dengo, G., and J.E. Case (Ed.), The Geology of North
America. The Geological Society of America, Boulder, Colo.

Ling H.-F., Burton K.W., O'Nions R.K., Kamber B.S., von Blankenburg F., Gibb A.J.,and
Hein J.R. (1997) Evolution of Nd and Pb isotopes in Central Pacific seawater
from ferromanganese crusts. Earth Planet. Sci. Lett. 146, 1-12.

Lyle M., Dadey K.A., and FarrellJ.W. (1995) The late Miocene (11-8 Ma) eastern
Pacific carbonate crash: Evidence for reorganization of deep-water circulation by
the closure of the Panama Gateway. In Proceedings ODP, Scientific Results,
Vol. 138 (ed. L. A. M. N.G. Pisias, and T.R. Janecek), pp. 821-838.

Martin E.E., and Haley B.A. (2000) Fossil fish teeth as proxies for seawater Sr and
Nd isotopes. Geochim. Cosmochim. Acta 64, 835-847.

Martin E.E., and Scher H. (2004) Preservation of seawater Sr and Nd in fossil fish
teeth: bad news and good news. Earth Planet. Sci. Lett. 220, 25-39.

Martin E.E., Macdougall J.D., Herbert T.D., Paytan A., and Kastner M. (1995) Sr and Nd
isotopic analyses of marine barite separates. Geochim. Cosmochim. Acta 59,
1353-1361.

Martini E. (1971) Standard Tertiary and Quaternary calcareous nannoplankton zonation.
In: Farinacci, A. (Ed.),Proc. 2nd Planktonic Conf. Roma, Rome.










Mayer L., Pisias N., Janecek T., et al. (1992) Proceeding of the Ocean Drilling Program,
Initial Reports. Ocean Drilling Program, College Station, TX.

Michard A.., Albarede F., Michard G., Minster J.F., and Charlou J.L. (1983) Rare-earth
elemetns and uranium in high-temperature solutions from East Pacific Rise
hydrothermal vent field (13-degrees-N). Nature 303, 795-797.

Mikolajewicz U., and Crowley T.J. (1997) Response of a coupled ocean/energy
balance model to restricted flow through the Central American isthmus.
Paleoceanography 12, 429-441.

Miller K.G., and Fairbanks R.G. (1985) Oligocene to Miocene carbon isotope cycles and
abyssal circulation changes. In: Sundquist, E. T., and W.S. Broecker (Ed.), The
Carbon Cycle and Atmospheric CO2: Natural variations Archean to Present.
Geophys. Monogr. Ser., AGU, Washington, DC.

Mix A.C., Tiedemann R., Blum P., et al. (2003) Proceedings of the Ocean Drilling
Program, Initial Reports. Ocean Drilling Program, College Station, TX.

Moore Jr. T.C., Shackleton N.J., and Pisias N.G. (1993) Paleoceanography and the
diachrony of radiolarian events in the eastern equatorial Pacific.
Paleoceanography 8, 567-586.

Muller-Karger F.E., McClain C.R., Fisher T.R., Esaias W.E., and Varela R. (1989)
Pigment distribution in the Caribbean Sea: Observations from space. Prog.
Oceanogr. 23, 23-64.

Mullins H.T., and Neumann A.C. (1979) Geology of the Miami Terrace and its
paleoceanographic implications. Marine Geology 30, 205-232.

Mullins H.T., Neumann A.C., Wilber R.J., Hine A.C., and Chinburg S.J. (1980)
Carbonate sediment drifts in the northern Straits of Florida. AAPG Bulletin 64,
1701-1717.

Mullins H.T., Gardulski A.F., Wise S.W., and Applegate J. (1987) Middle Miocene
oceanographic event in the eastern Gulf of Mexico: Implications for seismic
stratigraphic succession and Loop Current/Gulf Stream circulation. Geol. Soc.
Am. Bull. 98, 702-713.

Nisancioglu K.H., Raymo M.E., and Stone P.H. (2003) Reorganization of Miocene
deep water circulation in response to the shoaling of the Central American
Seaway. Paleoceanography 18(1), 1006, doi:10.1029/2002PA000767.

Nof D., and van Gorder S. (2003) Did an open Panama Isthmus correspond to an
invasion of Pacific water into the Atlantic? J. Phys. Oceanogr. 33, 1324-1336.










O'Nions R.K., Frank M., von Blanckenburg F., and Ling H.-F. (1998) Secular variation
of Nd and Pb isotopes in ferromanganese crusts from the Atlantic, Indian and
Pacific Oceans. Earth Planet. Sci. Lett. 155, 15-28.

Peters J.L., Murray R.W., Sparks J.W., and Coleman D.S. (2000) Terrigenous matter
and dispersed ash in sediment from the Caribbean Sea: results from Leg 165. In:
R.M. Leckie, S., H., Acton, G.D., and Draper, G. (Ed.),Proceeding of the Ocean
Drilling Program, Scientific Results Ocean Drilling Program, College Station, TX.

Piepgras D.J., and Wasserburg G.J. (1982) Isotopic composition of neodymium in
waters from the Drake Passage. Science 217, 207-214.

Piepgras D.J., and Wasserburg G.J. (1985) Strontium and neodymium isotopes in hot
springs on the East Pacific Rise and Guaymas Basin. Earth Planet. Sci. Lett. 72,
341-356.

Piepgras D.J., and Wasserburg G.J. (1987) Rare earth element transport in the
western North Atlantic inferred from Nd isotopic observations. Geochim.
Cosmochim. Acta 51, 1257-1271.

Piepgras D.J., and Jacobsen S.B. (1988) The isotopic composition of neodymium in
the North Pacific. Geochim. Cosmochim. Acta 52, 1373-1381.

Pinet B., Lajat D., Le Quellec P., and Bouysse P. (1985) Structure of Aves Ridge and
Grenada Basin from multichannel seismic data. In: Mascle, A.
(Ed.),Geodynamique des Caraibes. Editions Technip., Paris.

Piotrowski A. M., Goldstein S.L., Hemming S.R., and Fairbanks R.G. (2005) Temporal
Relationships of Carbon Cycling and Ocean Circulation at Glacial Boundaries.
Science.

Philander S.G.H., and Pacanowski R.C. (1986) A model of the season cycle in the
tropical Atlantic. J. Geophys. Res. 91, 14192-14206.

Poore H.R., Samworth R., White N.J., Jones S.M., and McCave I.N. (2006) Neogene
overflow of Northern Component Water at teh Greenland-Scotland Ridge.
Geochemistry, Geophysics, Geosystems 7.

Popenoe P. (1985) Cenozoic depositional and structural history of the North Carolina
margin from seismic stratigraphic analyses. In: Poag, C. W. (Ed.),Geologic
evolution of the United States Atlantic margin. Van Nostrand Reinhold, New
York.









Prange M., and Schulz M. (2004) A coastal upwelling seesaw in the Atlantic Ocean as a
result of the closure of the Central American Seaway. Geophys. Res. Lett. 31,
L17207.

Puteanus D., and Halbach P. (1988) Correlation of Co concentration and growth rate: A
method for age determination of ferromanganese crusts. Chemical Geology 69,
73-85.

Raffi I., and Flores J.-A. (1995) Pleistocene through Miocene calcareous nannofossils
from eastern equatorial Pacific Ocean (Leg 138). In Proc. ODP, Sci. Res., Vol.
138 (ed. N.G. Pisias, L.A. Mayer, and T.R. Janecek), pp. 233-286.

Reynolds B.C., Frank M., and O'Nions R.K. (1999) Nd- and Pb- isotope time series
from Atlantic ferromanganese crusts: implications for changes in provenance and
paleocirculation over the last 8 Myr. Earth Planet. Sci. Lett. 173, 381-396.

Roth J.M. (1998) The Caribbean carbonate crash at the middle to late Miocene
transition and the establishment of the modern global thermohaline circulation
[M.S. thesis], Rice University.

Roth J.M., Droxler A.W., and Kameo K. (2000) The Caribbean carbonate crash at the
middle to late Miocene transition: linkage to the establishment of the modern
global ocean conveyor. In Proc. ODP, Sci. Results, Vol. 165 (ed. R.M. Leckie,
Siquardssom, H., Acton, G.D., and Draper, G.), pp. 249-273.

Savin S.M., Keller G., Douglas R.G., Killingley J.S., Shaughnessy L., Sommer M.A.,
Vincent E., and Woodruff F. (1981) Miocene benthic foraminiferal isotope
records: A synthesis. Marine Micropaleontology 6, 423-450.

Scher H.D., and Martin E.E. (2004) Circulation in the Southern Ocean during the
Paleogene inferred from Nd isotopes. Earth Planet. Sci. Lett. 28, 391-405.

Scher H.D., and Martin E.E. (2006) Timing and climatic consequences of the opening of
Drake Passage. Science 312, 428-430.

Schneider B., and Schmittner A. (2006) Simulating the impact of the Panamanian
seaway closure on ocean circulation, marine productivity and nutrient cycling.
Earth Planet. Sci. Lett. 246, 367-380.

Schnitker D. (1980) North Atlantic oceanography as possible cause of Antarctic
glaciation and eutrophication. Nature 284, 615-616.

Segl M., Mangini A., Bonani G., Hofmann H.J., Nessi M., Sutter M., Wolfli W., Friedrich
G., Pluger W.L., Wiechowski A., and Beer J. (1984) 10Be dating of manganese
crust from Central North Pacific and implications for oceanic paleocirculation.
Nature 309, 540-543.










Shackleton N.J., Crowhurst S., Hagelberg T., Pisias N.G., and Schneider D.A. (1995a)
A new Late Neogene time scale: application to Leg 138 sites. In Proc. ODP, Sci.
Res., Vol. 138 (ed. N.G. Pisias, N.A. Mayer, T.R. Janecek, A. Palmer-Julson, and
T.H. van Andel), pp. 73-101.

Shackleton N. J., Baldauf J.G., Flores J.-A., Iwai M., Moore Jr. T.C., Raffi I., and Vincent
E. (1995b) Biostratigraphic Summary for Leg 138. In: Pisias, N. G., Mayer L.A.,
Janecek T.R., Palmer-Julson A., and van Andel T.H. (Ed.),Proc. ODP, Sci. Res.
Ocean Drilling Program, College Station, TX.

Shackleton N.J., and Hall M.A. (1995) Stable isotope records in bulk sediments (Leg
138). In: N.G. Pisias, N. A. M., T.R. Janecek, A. Palmer-Julson, and T.H. van
Andel (Ed.), In Proceedings of the Ocean Drilling Program, Scientific Results.
Ocean Drilling Program, College Station, TX.

Shackleton N.J., and Hall M.A. (1997) The late Miocene stable isotope record, Site 926.
In: Shackleton, N. J., Curry, W.B., Richter, C., and Bralower, T.J. (Ed.),Proc.
Ocean Drilling Prog., Scientific Results 154.

Shackleton N.J., and Crowhurst S. (1997) Sediment fluxes based on an orbitally tuned
time scale 5 Ma to 14 Ma, Site 926. In Proc. ODP, Sci. Results, Vol. 154 (ed. N.
J. Shackleton, Curray, W.B., Richter, C., and Bralower, T.J.), pp. 69-82.

Shaw H.F., and Wasserburg G.J. (1985) Sm-Nd in marine carbonates and phosphates:
Implications for Nd in seawater and crustal ages. Geochim. Cosmochim. Acta 54,
2433-2438.

Sigurdsson H., Leckie R.M., Acton G.D., et al. (1997) Proceeding of the Ocean Drilling
Program, Initial Reports. Ocean Drilling Program, College Station, TX.

Spivack A.J., and Wasserburg G.J. (1988) Neodymium isotopic composition of the
Mediterranean outflow and the eastern North Atlantic. Geochimica
Cosmochimica Acta 52, 2762-2773.

Staudigel H., Doyle P., and Zindler A. (1985) Sr and Nd isotope systematics in fish
teeth. Earth Planet. Sci. Lett. 76, 45-56.

Steph S., Tiedemann R., Prange M., Groeneveld J., Nurnberg D., Reuning L., Schulz
M., and Haug G.H. (2006) Changes in Caribbean surface hydrography during the
Pliocene shoaling of the Central American Seaway. Paleoceanography 21,
PA4221.

Tachikawa K., Jeandel C., and Roy-Barman M. (1999a) A new approach to the Nd
residence time in the ocean: the role of atmospheric inputs. Earth Planet. Sci.
Lett. 170, 433-446.










Tachikawa K., Jeandel C., Vangriesheim A., and Dupre B. (1999b) Distribution of rare
earth elements and neodymium isotopes in suspended particles of the tropical
Atlantic Ocean (EUMELI site). Deep-Sea REs. I: Oceanogr. Res. Pap. 46, 733-
755.

Tachikawa K., Athias V., and Jeandel C. (2003) Neodymium budget in the modern
ocean and paleo-oceanographic implications. Journal of Geophysical Research
108, 3254.

Talley L.D. (1993) Distribution and formation of North Pacific intermediate water.
Journal of Physical Oceanography 23, 517-537.

Thomas D.J., Bralower T.J., and Jones C.E. (2003) Nd isotopic reconstruction of Late
Paleocene-Early Eocene thermohaline circulation. Earth Planet. Sci. Lett. 290,
309-322.

Thomas D.J. (2004) Evidene for deep-water production in the North Pacific Ocean
during the early Cenozoic warm interval. Nature 430, 65-68.

Thomas D.J., and Via R.K. (2007) Neogene evolution of Atlantic thermohaline
circulation: Perspective from Walvis Ridge, southeastern Atlantic Ocean.
Paleoceanography 22, PA2212.

van de Flierdt T., Frank M., Halliday A.N., Hein J.R., Hattendorf B., Gunther D., and
Kubik P.W. (2004) Deep and bottom water export from the Southern Ocean to
the Pacific over the past 38 million years. Paleoceanography.

Via R.K.., and Thomas D.J. (2006) Evolution of Atlantic thermohaline circulation: Early
Oligocene onset of deep-water production in the North Atlantic. Geology 34, 441-
444.

von Blanckenburg F., and Igel H. (1999) Lateral mixing and advection of reactive
isotope tracers in ocean basins: observations and mechanisms. Earth Planet.
Sci. Lett. 169,, 13-128.

Wei W. (1995) The initiation of North Atlantic Deep Water as dated by nannofossils. J.
Nannopl. Res. 17, 90-91.

Wei W., and Peleo-Alampay A. (1997) Onset of North Atlantic Deep Water as dated by
nannofossils. Proceedings-30th International Geological Congress, Marine
Geology and Paleoceanography 13, 57-64.

Woodruff F., and Savin S.M. (1989) Miocene deepwater oceanography.
Paleoceanography 4, 87-140.









Wright J., Seymour R.S., and Shaw H.F. (1984) REE and Nd isotopes in conodont
apatite: Variations with geological age and depositional environment. GSA Spec.
Paper 196, 325-340.

Wright J.D., Miller K.G., and Fairbanks R.G. (1991) Evolution of modern deepwater
circulation: Evidence from the Late Miocene Southern Ocean.
Paleoceanography 6, 275-290.

Wright J.D., and Miller K.G. (1992) Early and middle Miocene stable isotopes:
implications for deepwater circulation and climate. Paleoceanography 7, 357-
389.

Wright J.D., and Miller K.G. (1996) Control on the North Atlantic Deep Water.
Paleoceanography 11, 157-170.









BIOGRAPHICAL SKETCH

Derrick Richard Newkirk was born in Indianapolis, Indiana. He is the eldest son of

Patricia and Richard Newkirk, and the older brother of Ryan Newkirk. His primary education,

elementary through high-school, was completed in Greenwood, Indiana. While attending

Indiana University Purdue University at Indianapolis he became interested in geology after

taking an introductory course taught by Bob Barr. After completion of his four years of

eligibility for collegiate soccer, he turned his focus to geology. During his undergraduate

education he worked as a lab assistant for Dr. Gabriel Filippelli, and helped Dr. Filippeli's Ph.D.

student at the time, Dr. Jennifer Latimer. While working under Dr. Gabriel Filippelli and Dr.

Jennifer Latimer he worked on his own research project looking at human impacts on the

watershed of Laguna Zoncho, Costa Rica using phosphorus geochemistry. This invaluable

experience doing scientific research led him to graduate school. He completed his degree in the

summer of 2004 with a Bachelor of Science with a focus in geology. At the University of

Florida his research focused on the Miocene carbonate crash using Nd in fossil fish teeth to

reconstruct ocean circulation. After completion of the Master of Science degree, he plans on

continuing at the University of Florida and pursuing his Ph.D. under the guidance of Dr. Ellen

Martin.





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1 NEODYMIUM ISOTOPIC STUDY OF OCE AN CIRCULATION DURING THE MIDDLE TO LATE MIOCENE CARBONATE CRASH By DERRICK RICHARD NEWKIRK A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2007

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2 2007 Derrick Richard Newkirk

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3 To my grandmother Addie Hair.

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4 ACKNOWLEDGMENTS I would like to sincerely thank Dr. Ellen Martin for her contin ued guidance on this project. Not only is she a great mentor, but also a good frie nd and a pleasure to work with. Thanks also go to my committee members Dr. David Hodell and Dr. John Jaeger for their advice and review of this thesis. Thanks also to Dr. Philip Neuhoff for the many insightfu l conversations we had pertaining to this research. I am also very grateful for the financial s upport that was provided by the NSF SGR grant awarded to Dr. Ellen Martin, the Department of Geological Sciences, and Graduate Student Council. Special thanks go to Susanna Blair for her gui dance and continuous help in the lab at the beginning of my graduate career. Also, I w ould like to thank Dr. George Kamenov for his assistance in the lab, help with analysis, and su ggestions for streamlining laboratory procedures. I would also like to thank Wende ll Phillips, Tracy King, Nicole Andersen and the many others who have helped me in the laboratory. Finally, I would like to thank my family and friends. Thanks go to Pat and Rick Newkirk for their unfaltering love and support. Thanks go to Ryan Newkirk for being a great friend and a very supportive brother. Thanks go to Scotti e Andre for playing a huge role in my upbringing and being a good role model. Thanks go to Laura Ruhl for her never ending love, encouragement, and support throughout this proc ess. Thanks go to my many wonderful friends in the Department of Geological Science at UF, especially Jonathan Hoffman, PJ Moore, Branden Kramer, Kris Crocket, Mike Ritorto, G illian Rosen, and Dorsey Wanless. Thanks to Dr. Gabriel Filippelli for his guida nce, friendship, and encouragemen t to continue on to graduate school. Thanks to Dr. Jennifer Latimer for her gu idance, friendship, and invaluable lab guidance that she gave me as an undergraduate researcher. And last but not least thanks go to all of my

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5 wonderful friends outside of the department a nd from my hometown, es pecially Jason Wright, Adam Faust, Judd Sparks, Dr. Gifford Waters Erica Roberts, Carlos Zambrano, and Ryan Fleming.

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6 TABLE OF CONTENTS page ACKNOWLEDGMENTS...............................................................................................................4 LIST OF TABLES................................................................................................................. ..........8 LIST OF FIGURES................................................................................................................ .........9 ABSTRACT....................................................................................................................... ............10 CHAPTER 1 INTRODUCTION..................................................................................................................12 2 BACKGROUND....................................................................................................................17 2.1 Neodymium Isotope Systematics.....................................................................................17 2.2 Archives of Nd Isotopes...................................................................................................18 2.3 Carbonate MAR.............................................................................................................. ..20 2.4 General Ocean Circulation...............................................................................................20 2.5 Caribbean Basin Tectonic Setting....................................................................................22 2.6 Modern Caribbean Basin Circulation...............................................................................23 2.7 Ocean Circulation Models................................................................................................23 2.8 Description of Sample Sites..............................................................................................24 2.8.1 ODP Site 846B.......................................................................................................24 2.8.2 ODP Site 998A.......................................................................................................25 2.8.3 ODP Site 999A.......................................................................................................26 2.8.4 Age Models............................................................................................................26 3 METHODS........................................................................................................................ .....30 3.1 Fossil Fish Teeth Sample Preparation..............................................................................30 3.2 Column Chemistry........................................................................................................... .30 3.3 Nd Analysis................................................................................................................ ......30 4 RESULTS........................................................................................................................ .......32 4.1 Neodymium Isotopic Ratios.............................................................................................32 4.2 Nd Compared to Carbonate MAR....................................................................................33 5 DISCUSSION..................................................................................................................... ....40 5.1 The Source of Caribbean Basin Nd Values in the Mi ddle/Late Miocene........................40 5.2 Circulation during the Caribbean Pr e-Crash and Pre-Crash Transition...........................43 5.3 The Caribbean Carbonate Crash.......................................................................................44 5.4 Circulation during the Caribbean Po st-Crash Transition and Post-Crash........................48

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7 5.5 The Pacific Carbonate Crash............................................................................................49 6 CONCLUSIONS....................................................................................................................62 LIST OF REFERENCES............................................................................................................. ..64 BIOGRAPHICAL SKETCH.........................................................................................................76

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8 LIST OF TABLES Table page 4-1 Nd isotopes of Fossil Fish Teeth from ODP Site 846........................................................37 4-2 Nd isotopes of Fossil Fish Teeth from ODP Site 998........................................................38 4-3 Nd isotopes of Fossil Fish Teeth from ODP Site 999........................................................39

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9 LIST OF FIGURES Figure page 1-1 Plate reconstruction........................................................................................................... .16 2-1 Simplified reconstruction of the Caribbean Region illustrating the locations of sites 998 and 999 from this study...............................................................................................28 2-2 Carbonate MAR records for sites 846, 998 and 999 from 8 to 14 Ma 29 4-1 Nd values from site 846 in the eastern equatorial Pacific, sites 999 and 998 in the Caribbean Basin plotted versus depth................................................................................35 4-2 Nd values and carbonate MARs from site 846 in the eastern equatorial Pacific and sites 999 and 998 in the Caribbean Basin spanning from 8 to 14.5 Ma............................36 5-1 Nd values and ash MARs from sites 999 and 998 in the Caribbean Basin spanning from 8 to 14.5 Ma..............................................................................................................51 5-2 Nd values from sites 998 and 999 in the Caribbean Basin, site 846 in the eastern equatorial Pacific, Fe-Mn crusts from the North Atlantic, Straits of Florida, North Pacific, central equatorial Pacific......................................................................................52 5-3 Nd and 13C values from site 998......................................................................................53 5-4 Nd and 13C values from site 999......................................................................................54 5-5 Flow patterns of Atlantic and Pacific waters durin g the Pre-Crash/Pre-Crash Transition intervals........................................................................................................... .55 5-6 Ndvalues from sites 998 and 999 in the Ca ribbean Basin spanning from 8 to 14.5 Ma. 56 5-7 Nd values from site 998, carbonate MAR, and %NCW....................................................57 5-8 Nd values from site 999, carbonate MAR, and %NCW....................................................58 5-9 Flow patterns of Atla ntic and Pacific waters during the Carbonate Crash interval...........59 5-10 Flow patterns of Atla ntic and Pacific waters during the Post-Crash Transition/PostCrash intervals................................................................................................................ ...60 5-11 Dissolved oxygen profile from the Pacific........................................................................61

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10 Abstract of Thesis Presen ted to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science NEODYMIUM ISOTOPIC STUDY OF OCE AN CIRCULATION DURING THE MIDDLE TO LATE MIOCENE CARBONATE CRASH By Derrick Richard Newkirk August 2007 Chair: Michael R. Perfit Major: Geology The term carbonate crash describes an extensive dissolution event (or series of events) marked by low carbonate mass accumulation rates (M ARs), which were originally observed in middle/upper Miocene sediments from the eastern equatorial Pacific and later discovered in western equatorial Atlantic and Caribbean Basin sediments. The timing of the crash suggests a change in global circulation pa tterns associated with the s hoaling of the Central American Seaway (CAS) may have brought more corrosiv e bottom waters to this region. This study presents the first neodymium (Nd) isotopic data fro m this region which has been used to identify the source of bottom waters and the basic circ ulation patterns in the Caribbean during this gateway event. The total range for Nd values measured for fossil fish teet h over the interval of interest for site 998 (Yucatan Basin) is -6.6 to 0 from 14.1 to 9.0 Ma. Values for site 999 (Colombian Basin) range from -6.4 to -0.1 for 14.0 Ma to 9.1 Ma, and va lues for site 846 (Peru Basin) range from -3.75 to -1.65 for 14.1 Ma to 8.1 Ma. During the carbonate crash intervals (low carbonate MARs), the Nd values shift to more radiogenic values at all three sites. The radiogenic Nd values recorded in the Caribbean are similar to Pacific intermediate waters, whic h suggest the flow of Pacific water from west to east through the CAS into the Caribbean Basin. This flow pattern

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11 agrees with several general oc ean circulation models studying the shoaling of the Isthmus of Panama, as well as 13C data. Middle to late Miocene Caribbean carbonate cr ash episodes also appear to correlate to intervals of increased producti on of Northern Component Water (NCW). For the Caribbean, periods of enhanced conveyor circulation asso ciated with enhanced NCW production appear to correlate with intervals when older, more corro sive intermediate Pacific waters passed through the CAS. Increased carbonate preservation in the Caribbean following the carbonate crash coincides with decreasing NC W production and less radiogenic Nd values, suggesting a gradual decline in Pacific waters flowing into the Cari bbean Basin as the Isth mus of Panama shoaled. In the Pacific, increased NCW production resu lted in a greater contribution of NCW to Circumpolar Water (CPW) and therefore older, more corrosive CPW, which ultimately formed more corrosive North Pacific Intermediate Water (NPIW) and Pacific Central Water (PCW). The southward migration of these water masses is documented by the progression of low carbonate MARs starting in the northern se ction of the eastern equatorial Pacific near the CAS at ~12 Ma, and moving further south to the location of site 846 by ~11.5 Ma. The carbonate crash interval at site 846 correlates with Nd values that shift upward to ~-2, a value consistent with the introduction of corrosive NPIW to this site.

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12 CHAPTER 1 INTRODUCTION The term carbonate crash was coined by Lyle et al. (1995) to describe an extensive dissolution event (or series of events), mark ed by low carbonate mass accumulation rates (MAR) during the middle/late Miocene that were obs erved during Ocean Drilling Program (ODP) Leg 138 in the eastern equatorial P acific (Farrell et al., 1995; Lyle et al., 1995). Subsequently, carbonate crash events have also been documented in the western equatori al Atlantic (Leg 154; King et al., 1997; Shackleton and Crowhurst, 1997), and the Caribb ean (Leg 165; Roth et al., 2000) (Figure 1-1). Theories for the carbonate cr ash include: 1) increased productivity resulting in enhanced decay (oxidation) of organic matte r on the seafloor, or 2) a change in global thermohaline circulation that in troduced more corrosive bottom water to the equatorial region. Lyle et al. (1995) noted that increased su rface productivity and the associated production of acid in the deep ocean during the degradation of la rge quantities of orga nic carbon would lead to more corrosive bottom waters, resulting in a decrease in carbona te MAR. However, Lyle et al. (1995) argued against this mechanism ba sed on a lack of evidence for increased Corg MAR at the time of the carbonate crash in the eastern equatorial Pacific, as well as a lack of a covariance between carbonate and opal MARs. Specifically, Lyle et al. (1995) believed increased surface productivity and associated deep water acidity should result in an increased Corg MAR and opal MAR, and decreased carbonate MAR. Alternatively, the carbonate crash may have resulted from a change in deep ocean circulation. In this scenario, intervals of low carbonate MAR are linked to the presence of more corrosive intermediate and deep water masses at sites around the Caribb ean region that supply deep waters to the Caribbean Basin (Roth et al ., 2000; Lyle et al., 1995; Farrell et al., 1995). The

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13 timing of the crash also suggests changing circulation pa tterns may have been associated with the shoaling of the Central American Seaway (CAS). Openings and closings of oceanic gateways ha ve been associated w ith reorganizations of ocean circulation and have been linked to dramatic climatic events throughout geologic time. An example of this is the opening of the Tasman Seaway and the Drake Passage, which have been linked to the onset of the Antarctic Circumpol ar Current (ACC), the thermal isolation of Antarctica, and the development of ice sheets on Antarctica (Kennett et al., 1974; Kennett, 1977; Exon et al., 2002; Scher and Martin, 2006). Previous studies of the effect of the clos ure of the CAS have focused on largescale changes in surface ocean circulation and the re sulting impact on climate (Keigwin, 1982; Keller et al., 1989; Coates et al., 1992; Moore et al., 1993; Haug and Ti edemann, 1998). However, this closure likely impacted deep water circulation pa tterns as well. Closure presumably redirected warm, saline surface waters from the Gulf of Me xico to the North Atlantic, thereby increasing the salinity and density of the deep water form ed in the Norwegian-Greenland-Labrador Seas. This increase in North Atlantic Deep Water (NADW) production would have occurred at the expense of North Atlantic Intermediate Water (NAIW), and the reduced NAIW would have been compensated by northward migration of Antarctic In termediate Water (AAIW). In this scenario, the water mass flowing over the shallow sills se parating the Caribbean from the Atlantic would depend on the position of the boundary between these two intermediate water masses. According to Roth et al. (2000), the water mass th at overflowed the shallow to intermediate sills and filled the deep Caribbean during times of enhanced carbonate preservation was primarily sourced from the north, while sout hern sourced waters dominated during corrosive intervals.

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14 In this scenario, the Southern Ocean b ecomes the primary location for deep-water formation during times of decr eased NADW production. Thus, th e deep water in the Pacific travels a shorter distance resul ting in a water mass with higher oxygen and lower nutrient levels. A similar process is observed in the eastern e quatorial Pacific during gl acial stages, which are accompanied by weaker NADW production. Le et al. (1995) observed greater carbonate preservation in the eastern equa torial Pacific during glacial stag es and greater dissolution during interglacial. When NADW productio n is strong, the deep water in th e Pacific has to travel from the North Atlantic. This longer tr avel path allows for more oxida tion of organic matter, resulting in increased concentrations of CO2 and nutrients, while decrea sed oxygen concentrations, and older, more corrosive bottom water in the eastern equatorial Pacific. This mechanism for the carbonate crash pres ented by Roth et al. (2000) is based on a model developed by Haddad and Droxler (1996) to account for Pleistocene deposits in the Caribbean that alternate between low carbonate accumulation during interglacial periods, and carbonate deposition during glacial periods. Hadd ad and Droxler (1996) suggested that high rates of NADW production during in terglacial periods resulted in corrosive AAIW overflowing the Caribbean sill and filling the Caribbean Basin, wh ile decreased NADW production during glacial periods resulted in NAIW overflowing the Caribbean sill a nd filling the Caribbean Basin. Roth et al. (2000) attempted to use carbon isotop ic data to identify the source of water entering the Caribbean Basin and test this th eory. They interpreted changes in 13C based upon the assumption that either NAIW or AAIW was overfl owing the sill to fill the Caribbean Basin, but they could not identify a specific water mass w ith this proxy. Carbon isotopes can give an indication of the age of the water mass, but th ey are not a unique proxy for water mass because they are not conservative trac ers (Kroopnick, 1985). In a ddition, carbon isotopic data are

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15 generally recovered from foraminifera, which are rarely preserved dur ing dissolution events (Shackleton and Hall, 1995, 1997; Roth et al., 2000). The goal of this study is to use neodymium (Nd) isotopes preserved in fossil fish teeth to test theories about ocean circulation duri ng the middle/late Miocene carbonate crash. Neodymium isotopes were used because they ar e generally viewed as quasi-conservative tracers of water masses, meaning they reflect th e initial signal of the s ource region, but can be modified by weathering inputs during circulat ion (Frank et al., 2003; Goldstein and Hemming, 2003). The end-member Nd isotopic compositions of the water masses in the Miocene are relatively well constrained by published data for Fe -Mn crusts and fish teeth (Burton et al., 1997 and 1999; Ling et al., 1997; ONions et al., 1998 ; Martin and Haley, 2000; Frank et al., 2002; van de Flierdt et al., 2004; Scher and Martin, 200 4). In addition, fossil fish teeth are abundant throughout the dissolution events, making them excelle nt archives to recons truct paleocirculation during these events. Results of this research suppor t the hypothesis that changes in deep water circulation are associated with the carbonate crash intervals in the Caribbean and Pacific; however, the most corrosive bottom waters appear to be derived from the Pacific rather than the Atlantic. This scenario suggests west to east flow through the CAS in the middl e Miocene in response to the shoaling of the CAS and Northern Component Water (NCW) production.

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16 Figure 1-1. Plate reconstruction from the Ocean Drilling Stratigraphic Network (www.odsn.de ) with ODP and Ferromanganese Crust Locations discussed in this study. 844 (3,414m) BM1969.05 (1,829m) ALV539 (2,655m) 926 (3,598m) 999 (2,828m) 846 (3,296m) GMAT14D (4,000 3400m) BM1963.897 (850m) 998 ( 3 179m ) CD29-2 (2,390-1.970m)D11-1 (1,870-1,690m) D4-13A (Alaska) (2,100m) 13D-27A (Kamchatka) (1,800-1,500m) 845 (3,704m) 1241 (2,027m)

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17 CHAPTER 2 BACKGROUND 2.1 Neodymium Isotope Systematics The light REE (Rare Earth Element) Ne odymium (Nd) has seven isotopes. 143Nd is the radiogenic daughter product of 147Sm (half-life = ~1.06x1011 years), which is produced by alpha decay. 144Nd is used as a reference because it is a stable isotope, thus the number of atoms should not change as long as the system remains closed. The143Nd/144Nd ratio is reported as Nd in order to report small but significa nt variations as whole numbers. Nd is calculated using the equation: Nd(0)=[(143Nd/144Nd)sample/(143Nd/144Nd)CHUR-1] x 104 where CHUR (Chondritic Uniform Re servoir) equals the bulk earth 143Nd/144Nd of ~0.512638 (DePaolo and Wasserburg, 1976). The primary sources of Nd to seawater ar e continentally derived dust, volcanic ash, resuspended detrital sediments, and riverine inputs in the form of either dissolved or particulate material (Goldstein and Jacobsen, 1988; El derfield, 1988; Spivack and Wasserburg, 1988; Bertram and Elderfield, 1993; Gr eaves et al., 1994; Henry et al., 1994; Jeandel et al., 1995, Albarede et al., 1997; Frank, 2002; Tachikawa et al., 1999 and 2003). Hydrothermal sources of Nd to the ocean are insignificant, because Nd is quantitatively scavenged by oxides near the midocean ridge (Michard, 1983; German et al., 1990). Nd concentrations in seawater are fairly low, ~4pg/g in deep water, because Nd ions are relati vely insoluble and extremely particle reactive. In a situation that has been te rmed the Nd Paradox, Nd concentra tions vary along the path of the global conveyor belt, but Nd isotopes behave as conservative tracers (G oldstein and Hemming, 2003; Lacan and Jeandel, 2001; Jeandel et al., 1995, 1998; Tachikawa et al., 1999a, 1999b; Bertram and Elderfield, 1993). Specifically, Nd concentrations are low in surface waters, but

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18 higher in deep waters, and concen trations in the Pacific are highe r than the Atlantic (Goldstein and Hemming, 2003); however, Nd isotopes in mode rn core tops correlat e well with salinity, a conservative property in seawater (See re view in Goldstein an d Hemming, 2003). Another important characteristic of Nd is th at its residence time in seawater is 600-1000 years (Tachikawa et al., 1999; Elderfield and Greaves, 1982; Piepgras and Wasserburg, 1985; Jeandel et al., 1995); which is shorter than the mixing time of the ocean at ~1500 years (Broecker and Peng, 1982). Due to this relatively short residence time, different ocean basins have distinct Nd isotopic ratios (Table 1), whic h also vary vertically within the water column (Piepgras and Wasserburg, 1987; Bertram and Elde rfield, 1993; Jeandel, 1993). Modern NADW has an Nd value of ~ -14, which reflects the weathe ring of Archean age rocks from the North American craton (Piepgras and Wasserburg, 1987 ). Modern Pacific deep water has an Nd of ~ 4, which is the result of young, circum-Pacific volcanogenic sources (Piepgras and Jacobsen, 1988), while modern North Pacific Intermediate Water (NPIW) reflects an even stronger influence from radiogenic volca nic material and has an Nd value of ~ -2.5 (Piepgras and Jacobsen, 1988). Finally, Anta rctic Bottom Water (AABW) and Antarctic Intermediate Water (AAIW) have Nd of ~ -8 (Piepgras and Wasserburg, 1982; Jeandel, 1993), which represents mixing of the Atlantic and Pacifi c water masses. For comparison, the analytical uncertainty for Nd isotopic measurements for this study is 0.35 Nd units. Therefore, the values for the various end members are analytically distinct. 2.2 Archives of Nd Isotopes Sedimentological archives such as ferroma nganese (Fe-Mn) crusts and nodules, Fe-Mn oxide coatings, and fossil fish teeth have been used to estimate the Nd values of past water masses. Data from Fe-Mn crusts and nodules illust rate that the major ocea n basins have distinct isotopic compositions (Albarede and Goldstein, 1992; Abouchami et al., 1997; Burton et al.,

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19 1997; Ling et al., 1997; Frank and ONions, 1998; Frank et al., 1999 and 2002; von Blackenburg and Igel, 1999); however, Fe-Mn crusts yield ve ry low resolution record s due to their slow growth rates (1-15mm/Myr; Segl et al., 1984; Puteanus and Halback, 1988). In addition, the crusts have a sparse distribution, which inhibits large-scale sampling because they only grow where sedimentation rates are extremely slow or currents sweep away hemipelagic sediment. Finally, age control for Fe-Mn crusts, which ar e dated using Be, is poor beyond 10 Ma because 10Be has a half-life of 1.5 x 106 years. Overall, the slow growth rate of the Fe-Mn crusts records long-term trends and variations in ocean circulat ion, but they do not record the more rapid shifts in circulation that are frequently associated with climatic events because their signal is integrated over time. Fossil fish teeth, on the other hand, can be da ted accurately with the surrounding sediment using magnetostratigraphy, biostratigraphy, and chemostratigraphy, thereby allowing the development of higher resolution records. Fossil fish teeth, which are composed of hydroxyflourapatite, have been shown to be eff ective recorders of bottom water Nd isotopic values (Elderfield and Pagett, 1986; Martin a nd Haley, 2000; Thomas et al., 2003; Martin and Scher, 2004; Thomas, 2004; Scher and Martin, 20 06). The hydroxyapatites of living fish teeth have Nd concentrations in the ppb range (W right et al., 1984; Shaw and Wasserburg, 1985), while the hydroxyfluorapatite of fossil fish t eeth have Nd concentrations of 100 to 1000 ppm (Wright et al., 1984; Shaw and Wasserburg, 1985; St audigel et al., 1985; Ma rtin et al., 1995). Fossil fish teeth appear to incorporate Nd during the early diagenetic transformation of hydroxyapatite to hydroxyfluorapatite at the sediment-water interface, while the teeth are still in contact with ocean bottom waters (Wright et al ., 1984; Shaw and Wasserburg, 1985; Staudigel et al., 1985; Martin et al., 1995; Ma rtin and Haley, 2000; Martin a nd Scher, 2004). Martin and

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20 Haley (2000) have demonstrated that fossil fish teeth record similar is otopic ratios to Fe-Mn crusts when they are exposed to similar bot tom waters. Given evidence that the initial Nd values are preserved over time (Martin a nd Scher, 2004), the Nd signals from fossil fish teeth have been used by Scher and Martin (2004, 2006), Thomas et al. (2003), Via and Thomas (2006), and Thomas and Via (2007) to tr ack paleocirculation. 2.3 Carbonate MAR Carbonate mass accumulation rates (CO3 MARs) are determined by the following equation: MAR x CaCO3wt% x 100 = CO3 MAR To calculate the CO3 MAR, the bulk mass accumulation rate (bulk MAR) and the calcium carbonate weight content (CaCO3wt%) must be known. The bulk MARs were calculated by multiplying dry bulk density (grams of dry sedi ment per wet volume in cubic centimeters) by a calculated linear sedimentation rate (m/m.y.) (Roth et al., 2000). The CaCO3wt% was determined for each sample using a carbonate bomb (Roth et al., 2000). Mass accumulation rates and carbonate mass accumulati on rates for this study were taken from Roth et al. (2000) for the two Caribbean Basin sites (998 and 999), and from Farrell et al. (1995) for eastern equatorial Pacific (site 846). It is important to use car bonate MAR rather than CaCO3wt% to identify changes in the carbonate system, because CaCO3wt% is influenced by dilution from other fractions such as terrigenous matter, volcani c ash, and/or silica. 2.4 General Ocean Circulation The modern general ocean circulation model is controlled by the sinking of cold, saline surface waters in the high latit udes. Initially, water in the de sert latitudes of the Atlantic becomes warm due to solar radiation and saline du e to evaporation. This warm-saline water then

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21 moves north into the Norwegian-Greenland Sea as pa rt of the Gulf Stream. As the water travels into the North Atlantic it cools. When the wa ter finally reaches the Norwegian-Greenland Sea it cools until it becomes dense enough to set up an inverse density gradient, allowing the dense overlying water mass to sink. This sinking wate r mass mixes with Labr ador Sea water and becomes North Atlantic Deep Water (NADW), which travels al ong the western margin of the Atlantic and ultimately mixes with Antarc tic Bottom Water (AABW) in the Antarctic Circumpolar Current (ACC) to form Circumpolar Deep Water (CDW). This mixture eventually flows northward into the Indian Ocean and Paci fic Ocean. Along its circ ulation paths in the Indian and Pacific Oceans CDW mixes upward w ith intermediate and surface waters. These Intermediate and surface waters then flow south from the north Pacific to the south Pacific as either North Pacific Intermediate Water (NPIW) or Pacific Central Water (PCW). The southward flowing water leaves the Pacific Ocean either through the Indonesian Seaway or the Drake Passage, ultimately flowing back into th e Atlantic Ocean. Once these waters enter the Atlantic Ocean, they follow the surface gyre circul ation back to the equatorial region, thereby starting the cycle over again. This circular path of water has b een termed the global conveyor by Broecker and Peng (1982) and takes approxima tely 1,500 years to complete (Broecker and Peng, 1982). The global conveyor can be altered by the closing/opening of oceanic gateways or the introduction of fresh water. The CAS began clos ing during the middle to late Miocene creating a barrier between the equatorial Atlantic and Pacific Oceans (Roth et al., 2000). The resulting change in circulation may have affected the re distribution of heat and nutrients throughout the ocean.

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22 2.5 Caribbean Basin Tectonic Setting Today the Caribbean Basin is bound by Central America to the west, the Lesser Antilles and Aves Swell to the east, and the Nicaragua Rise and Greater Antilles to the north (Droxler et al., 1998). The Aves Swell has behaved as a re mnant arc since ~55 Ma (Bird et al., 1993), and according to Droxler et al. (1998) the topographic highs experienced neritic conditions from ~50 15 Ma based on seismic surveys, drilling, and dredging, and then deeper conditions after 15 Ma. The two intermediate depth passageways (Windward Passage (1500 m) and the AnegadaJungfern Passage (1800m) (Figure 21) were the result of acceler ated subsidence of the Aves Swell to depths of 600 m to 1200 m during the mi ddle Miocene (Pinet et al., 1985; summarized in Droxler et al., 1998). The Nicaragua Rise is a series of carbona te banks and barrier reefs that created a prominent barrier to circulati on during the Oligocene to middle Miocene in the Caribbean and spanned from Nicaragua and Honduras to Jamai ca (Lewis and Draper, 1990; Droxler et al., 1992, 1998; Cunningham, 1998) (Figure 2-1). According to Droxler et al. (1992), foundering of the Nicaragua Rise occurred in the middle Miocene (~15-12 Ma), but could ha ve begun as early as late early Miocene (20-15 Ma). Faulting along the rise led to the ope ning of the north/south oriented Pedro Channel and the northern part of the Walton Basin (Cunningham, 1998). Using benthic foraminiferal assemblages from Atrato Basin located in the NW corner of South America, Duque-Caro (1990) suggested that the Isthmus of Panama shoaled to a depth of ~2000 m by ~15.9 15.1 Ma (ages adjusted to Shack leton et al., 1995a) and to a depth of ~1000 m between 12 10.2 Ma (ages adjusted to Shacklet on et al., 1995a). Shoa ling of the Isthmus of Panama to 100 m occurred by 4.6 Ma and final cl osure of the Central America Seaway occurred by ~3.5 Ma was suggested by Haug and Tiedemann (1998) based on a salin ity increase recorded in planktonic foraminifera.

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23 2.6 Modern Caribbean Basin Circulation The flow of shallow waters into the Cari bbean Basin is controlled by both changes in meridional overturning in the North Atlantic an d changes in the positi on of the Intertropical Convergence Zone (ITCZ) (Johns et al., 2002). Acco rding to Johns et al. (2002), almost all of the wind driven flow into the Caribbean occurs no rth of 15N (north of Martinique). During the summer a cyclonic circulation cell sets up southeast of the Lesser Antilles blocking the flow of the Guyana Current into the Cari bbean (Muller-Karger et al., 1989) while the ITCZ is located at its northernmost position (6-10N) (P hilander and Pacanowski, 1986). Intermediate depth sills that extend from Ven ezuela to the Greater Antilles restrict flow from the Atlantic into the Caribbean. The two most important connections today are the Windward Passage (1500 m) and the AnegadaJungfern Passage (1800m) (Pinet et al., 1985; Figure 2-1). Because of these sills, bottom water in the Caribbean Basin is sourced by intermediate depth waters from the Atlantic. Today, the water masses flowing into the Caribbean over these sills ar e upper NADW (uNADW), which orig inates at depths of ~1400 ~3500 m and AAIW, which originates at de pths of 800-1400 m (Haddad, 1994; Haddad and Droxler, 1996). These two water masses mix toge ther upon entering and fill the lower reaches of the Caribbean basins as a result of turbul ent mixing. Roth (1998) showed that water temperatures below the sill depths in the Caribbean are distinct from waters of the same depth in the Atlantic. Specifically, waters within the Caribbean basin are warmer and more homogeneous. These temperatures indicate that the deep waters filling the Caribbean basins have an origin shallower than 1500 m (Roth, 1998). 2.7 Ocean Circulation Models Flow of Pacific water through an open CAS in to the Atlantic was the result of several general ocean circulation models evaluating the effects of shoa ling of the Isthmus of Panama,

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24 NADW production, and the location of the ITCZ (e.g., Mikolajewicz and Crowley, 1997; Nisancioglu et al., 2003; Nof and van Gorder, 2003; Prange and Schultz, 2004; Klocker et al., 2005; Schneider and Schmittner, 2006; Steph et al., 2006). Model results of Schneider and Schmittner (2006) showed that when the isthmus s hoaled to 2000 m the deep waters flowed from the Atlantic to the Pacific, wh ile the intermediate (>800 m) and surface waters flowed from the Pacific to the Atlantic. The m odel presented by Nisancioglu et al (2003) indicated that Pacific intermediate waters began to flow through the CAS once the Isthmus of Panama shoaled to 1000 meters as a result of steric sea level differences between the Pacific and Atlantic. The production of NADW affected the m odel results of Nof and Van Gorder (2003). Their results showed that the net transport of wa ter through the CAS would be westward without the formation of NADW, while a high rate of NADW production would lead to eastward flow through the CAS. In the model presented by Steph et al. (2006), the major ity of the flow through the CAS was again from the Pacific to the Atlantic as a result of ster ic sea level differences, with the exception of the Ekman-dominated surface layer. This surface layer is affected wh en the ITCZ is located in its southernmost location and the northeast trade wind s profoundly effect steric sea level differences in the gateway region diminishing the e ffects at the surface (Steph et al., 2006). 2.8 Description of Sample Sites 2.8.1 ODP Site 846B Site 846B (3.696S, 90.078W; 3296 m water depth) is located within the Peru Basin (Figure 1-1). Coring recovered a continuo us record of the earl y/middle Miocene boundary at this site (Mayer, Pisias, Jan ecek, et al., 1992). The total dept h of penetration of hole 846B was 422.4 mbsf (meters below seafloor), which corres ponds to an age of ~16 Ma (Mayer, Pisias, Janecek, et al., 1992). The samples used in this study came from 272.3 to 371.5 mbsf, which corresponds to an age range of 8.1 to 14.1 Ma. From 272.3 to 317 mbsf (8.1 to 10.8 Ma) the

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25 samples are composed of clayey radiolarian diatom ooze interbedded with minor diatom nannofossil ooze (Mayer, Pisias Janecek, et al., 1992). Fr om 317 to 371.5 mbsf (10.8 to 14.1 Ma) the sediments are composed of nannofoss il ooze with minor amounts of biogenic silica (Mayer, Pisias, Janecek, et al., 1992). From 14.1 to 11.5 Ma the carbonate MA Rs ranged from 0.66 to 1.43 g/cm2 per k.y. (Figure 2-2) (Farrell et al., 1995) with an average value of ~0.9 g/cm2 per k.y. After 11.5 Ma the carbonate MARs decrease to levels ra nging in values between 0.73 and 0.04 g/cm2 per k.y. until 8 My, with the exception of a spike to ~1.24 g/cm2 per k.y. at 10.7 Ma (Farrell et al., 1995). 2.8.2 ODP Site 998A Site 998A (19.377N, 82.166W; 3101 m wate r depth) is located on the northern flank of the Cayman Rise in the Yucatan Basin (Figure 1-1). A continuo us Cenozoic section was recovered recording the evoluti on of Caribbean ocean circulati on (Sigurdsson, Leckie, Acton, et al., 1997). The total depth of penetration of hole 998A was 637.6 mbsf (~50 Ma) (Sigurdsson, Leckie, Acton, et al., 1997). The samples us ed in this study came from 132.5 to 177.7 mbsf, which corresponds to an age range of 9 to 14 Ma. From 132.5 to 161 mbsf (9 to 12.1 Ma) the samples are composed of nannofo ssil ooze with clay and nannofossil mixed sediments, and from 161 to 177.7 mbsf (12.1 to 14 Ma) they are co mposed of clayey nannofossil chalk and nannofossil mixed sediment (Sigurdss on, Leckie, Acton, et al., 1997). The carbonate MARs ranged between 0.54 and 0.86 g/cm2 per k.y. with an average of ~0.75 g/cm2 per k.y. (Figure 2-2) (Roth, 1998). From 12 to 10 Ma the values ranged between 0 and 0.7 g/cm2 per k.y. with lows from 12-11.8, 11.6-11.4, 11-10.8, 10.6-10.5, and 10.2 Ma (Roth, 1998). After 10 Ma, the values return to an average of ~0.75 g/cm2 per k.y. (Roth, 1998).

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26 2.8.3 ODP Site 999A Site 999A (12.639N, 78.360W; 2839 m water depth) is located on the Kogi Rise within the Colombian Basin (Figure 1-1; Sigurdss on, Leckie, Acton, et al., 1997). This site was selected in the hopes of recoveri ng a continuous core that recorded the progressive closure of the Central American Seaway (Sigur dsson, Leckie, Acton, et al., 1997) A total of 566.1 m of core was recovered from site 999A (Sigurdsson, Leckie Acton, et al., 1997), which correlates to an age of ~22.3 Ma (Peters et al., 2000). The samples used in th is study came from 243.9 to 351.4 mbsf, which corresponds to 8.8 to 14 Ma. Fr om 243.9 to 346.9 mbsf (8.8 to 13.8 Ma), the samples are composed of indurated clayey nanno fossil to clay with nannofossils, and from 346.9 to 351.4 mbsf (13.8 to 14 Ma) they are composed of clayey calcareous chalk with foraminifers (Sigurdsson, Leckie, Acton, et al., 1997). Carbonate MARs gradually decrease from ~2 g/cm2 per k.y. to ~1 g/cm2 per k.y. from 14.2 to ~12.1 Ma with significant decreases to values <0.5 g/cm2 per k.y. at 13.55, 13.05, and 12.55 Ma (Figure 2-2) (Roth, 1998). The larg est decreases in carbonate MARs occurred between 12 and 10 Ma with valu es ranging between 0 and 1 g/cm2 per k.y., with lowest accumulations occurring at 12.0-11.8, 11.6-11.4, 11.0-10.8, 10.6-10.5, and 10.2 Ma (Roth, 1998). Carbonate MAR values in creased from ~1 to ~1.5 g/cm2 per k.y. from 10 to 9 Ma (Roth, 1998). 2.8.4 Age Models The age/depth model used for site 846B (Figure 2-3) is based on nannofossil biostratigraphy of Raffi and Flores (1995) in which they used zonal boundaries defined by Martini (1971) and Bukry (1973). The ages of these zonal boundaries and magnetic reversals (Mayer, Pisias, Janecek, et al., 1992) were recalib rated to ages determined by Shackleton et al. (1995a) using orbital tuning. The age/depth m odels for sites 998 and 999 were based on the

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27 same zonal boundaries of Raffi and Flores (1995) and the recalibrated ages of Shackleton et al. (1995a) by Kameo and Bralower (2000). Therefore the age models for all three sites were done using the same age/depth models. Shackleton et al. (1995b) determined that the age uncertainty of the nannofossils was .1 Ma.

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28 Figure 2-1. Simplified reconstruction of the Caribbean Region illustrating the locations of sites 998 and 999 from this study (after Pind ell (1994) and modified from Roth et al. (2000). Windward Passa g e ( 1500 m ) Anegade Jungfern Passa g e ( 1800 m ) Northern Nicara g ua Rise Isthmus of Panama Site 999 Site 998

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29 Figure 2-2. Carbonate MAR records for sites 84 6, 998 and 999 from 8 to 14 Ma from Roth et al. (2000) 0.0 0.5 1.0 1.5 2.0 Site 998 Age (Ma) CaCO3 MAR 0.0 0.5 1.0 1.5 2.0 Site 846 891011121314 0.0 0.5 1.0 1.5 2.0CaCO 3 MAR Site 999 CaCO3 MAR

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30 CHAPTER 3 METHODS 3.1 Fossil Fish Teeth Sample Preparation Sediment samples were oven dr ied, disaggregated and wet siev ed prior to picking fossil fish teeth from the >125 m fraction. The fossil fish teeth were then cleaned using an oxidative/reductive cleaning technique from Boyl e (1981) and Boyle and Keigwin (1985). The oxidative/reductive cleaning techni que removed organic matter and oxide coatings, which allows for the analysis of isotopic rati os that are purely from the teeth. The cleaned teeth were dissolved in aqua regia to remove additional organic ma terial and then dried prior to the chemical separation of Nd. Concentrations of Nd in the teeth typically range from 100 to 400 ppm (Martin and Haley, 2000), and ~100 g of cleaned teeth were used for analyses. 3.2 Column Chemistry Effective isolation of Nd is a two step process. The first se t of quartz columns, or primary columns, isolate the bulk rare ear th elements (REEs) from the sample using Mitsubishi cation exchange resin with HCl as the eluent. The disso lved teeth were dried an d re-dissolved in 50 L of 0.75 N HCl and the REEs were eluted using 4 .5 N HCl after the removal of Ca, Sr, and Ba using a standard procedure (Sch er and Martin, 2004). After collection, the bulk REE samples were again dried and re-dissolved with 200 L of 0.18 N HCl and passed through quartz columns packed with Teflon beads coated with bis-ethylhexyl phosphoric acid, to separate Nd and Sm from the other REE. 3.3 Nd Analysis Nd isotopic ratios of the fossil fish teeth sa mples were analyzed using a Nu Plasma MultiCollector-Inductively Coupled Plasma-Mass Spect rometer (MC-ICP-MS) at the University of Florida. Dried samples were re-disso lved with 0.3 mL of 2% optima HNO3, then 0.01 mL of the

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31 sample was pipetted into a Teflon sampling b eaker and diluted with 0.99 mL of 2% optima HNO3. Additional acid or sample was added as needed to achieve the ideal voltage range of 2-6 volts for 143Nd. Belshaw et al. (1998) describe the instrument and the optimal operating conditions for the Nu-MC-ICP-MS. JNdi-1 stan dard was run 5 to 10 times each day, depending on the number of analyses acquired. A daily aver age for the standard was calculated for each run, and the samples for that run were corrected to the long-term running average of the JNdi-1 standard from the TIMS, which has a 143Nd/144Nd of 0.512102 (.000012, 2 ). A drift correction was not necessary because variations throughout a run did not indicate a consistent drift. The 2 error varied on a daily ba sis, but the long-term 2 error is 0.35 Nd units.

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32 CHAPTER 4 RESULTS 4.1 Neodymium Isotopic Ratios The total range in Nd values at site 846 (Peru Basin) is from -3.75 to -1.65 (Figure 4-1, Table 4-1). In the oldest pa rt of the record at 14.1 Ma, Nd begins at -3.75 a nd slowly shifts to more radiogenic Nd values up core (Figure 4-2). From 14.1 to 12.4 Ma the Nd values increase to -2.3. From 12.4 to 12.0 Ma Nd values shift to less radiog enic values of -3.07. The Nd values increase to ~-2.0 at 12.0 Ma and generally remain near that value until 8.4 Ma with a brief shift to -2.93 at 10.6 Ma. After 8.4 Ma Nd decreases to -2.9 at 8.1 Ma. The range in Nd values at site 846 (Peru Basin) is much smaller than the Caribbean sites. The total range for Nd values over the interval of intere st at site 998 (Yucatan Basin) is from -6.6 to 0 (Figure 4-1,Table 4-2). The Nd values remain relativel y constant ~-4.0 from 14.1 to 12.2 Ma (Figure 4-2). From 12.2 to 10.1 Ma the Nd values become more variable, ranging from -5.6 to 0 with a minimum baseline that decreases from ~-4 to -5.6. From 10.1 to 9.0 Ma Nd values slowly decrease to a value of ~-6.6. The total range of Nd values for site 999 (Colombian Basi n) is from -6.4 to -0.1 (Figure 41, Table 4-3). From 14.0 Ma to 13.7 Ma the Nd values increase from -5 .5 to -3.1 (Figure 4-2). Values remain around ~-3.0 from 13.7 to 12.1 Ma. At 12.0 Ma there is one point with a non radiogenic value of -6.4. After this, the Nd values become more variable. From 12.0 to 10.6 Ma the Nd values range from -3.0 to -0.1, and from 10.6 to 10.2 Ma values demonstrate a smaller range of variability range from -3.0 to -4.4. The Nd values shift to more radiogenic values of ~-2.0 from 10.2 to 9.4 Ma, and then decrease to -6.0 from 9.4 to 9.1 Ma. The final point at 9.0 Ma increases to -4.8.

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33 4.2 Nd Compared to Carbonate MAR The records for site 998 and 999 have been broken down into five intervals (pre-crash, pre-crash transition, crash, post-crash transition, and post-crash) based on the Nd and the carbonate MAR records (Figure 4-2). During the pre-crash interval at site 998 (>13.5 Ma), the carbonate MAR and the Nd signals are relatively steady with Nd values around ~-4 and carbonate MAR around ~0.75. At site 999, Nd values become more radiogenic, shifting from -5.5 to -3.1 during the pre-cras h interval (>13.5 Ma), while th e carbonate MAR decreases from ~2 to 1.25 g/cm2 per k.y. During the pre-crash transition interval (13.5 12 Ma), the Nd values at sites 998 and 999 are relatively stable with values ranging between -4.3 to -3.5 and -3.7 to -2.4 respectively. The carbonate MARs at site 999 range from 0 to 1.5 g/cm2 per k.y. and are more variable during the pre-crash transition, while, those at site 998 are relatively constant at ~1.25 g/cm2 per k.y. During the crash inte rval (12-10 Ma) the Nd values are much more variable with values ranging from -3.9 to 0 at site 998, and from -4.4 to -0.1 at site 999. The carbonate MARs at both sites are highly variable with values as low as ~0 and as high as ~1.3 g/cm2 per k.y. There is a general negative correla tion between low carbonate MAR and radiogenic Nd values at both sites during the crash interval. The post-crash transition and post-crash inte rvals are marked by increased carbonate MAR with values around ~1.0 at both sites. At site 998, the Nd values decrease from ~-5.5 to ~-6 over the combined sections. At Site 999, the Nd values increase to ~-2 durin g the post-crash transition interval, then decrease to ~6 during the post crash interval. At site 846, low carbonate MAR occurs later th an in the Caribbean basin, and the record has been divided into just two intervals (pre-c rash and crash) because the post-crash recovery

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34 was not recorded by this dataset and smaller subdivisions are not warranted. During the precrash interval ( 14.14 to 11.2 Ma), the Nd values begin at -3.8 and increase to more radiogenic values around ~-2, while carbonate MARs are ~0.5 to 1.0 (Figure 4-2). During the crash interval (11.2 to 8.1 Ma) carbonate MARs are ~0 to 0.5 and Nd values remain relatively stable ranging between ~-1.7 and -2.3 with a s hort shift to -2.93 at 10.6 Ma and a decrease to -2.9 at 8.09 Ma, which correlates with a brief increase in carbonat e MAR. Site 846 also shows a general negative correlation between low carbonate MAR and radiogenic Nd values during the carbonate crash interval, similar to the correlation observe d at sites 998 and 999.

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35 270280290300310320330340350360370 Nd -7 -6 -5 -4 -3 -2 -1 0 Site 846 250260270280290300310320330340350 Nd -7 -6 -5 -4 -3 -2 -1 0 Site 999 Depth (mbsf) 135140145150155160165170175180 Nd -7 -6 -5 -4 -3 -2 -1 0 Site 998 Figure 4-1. Nd values from site 846 in the easter n equatorial Pacific, sites 999 and 998 in the Caribbean Basin plotted versus depth.

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36 Figure 4-2. Nd values and carbonate MARs from site 846 in the eastern equatorial Pacific and sites 999 and 998 in the Caribbea n Basin spanning from 8 to 14.5 Ma. Carbonate MARs for site 846 are from Fa rrell et al. (1995) and for sites 999 and 998 are from Roth et al. (2000). Based on carbonate MARs site 846 is divided into two intervals, pre-crash and crash, and the two Caribbean sites are divided into five intervals (pre-c rash, pre-crash transition, cr ash, post-crash transition, and post-crash). Nd -6 -4 -2 0 Site 998 0.0 0.5 1.0 1.5 2.0 Age (Ma) CaCO 3 MAR 0.0 0.5 1.0 1.5 2.0 Nd -4 -3 -2 -1 Site 846 8.08.59.09.510.010.511.011.512.012.513.013.514.014.5Nd -6 -4 -2 0 Site 999 0.0 0.5 1.0 1.5 2.0 Crash Pre-Crash Transition Pre-Crash Post-Crash Post-Crash Transition Crash Pre-Crash

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37 Table 4-1. Nd isotopes of Foss il Fish Teeth from ODP Site 846. Sample Depth (mbsf) Age (Ma) 143Nd/144Nd Nd(o) 2 846B-29X-6W 61-67 272.348.090.512488-2.93 0.35 846B-30X-3W 110-116 278.038.430.512549-1.75 0.35 846B-31X-1W 77-83 284.308.810.512547-1.78 0.35 846B-31X-2W 101-107 286.048.920.512523-2.25 0.35 846B-31X-4W 98-104 289.029.100.512535-2.02 0.35 846B-31X-6W 101-107 292.049.290.512529-2.27 0.35 846B-32X-4W 103-109 298.669.690.512534-2.04 0.35 846B-32X-6W 27-33 300.909.820.512530-2.12 0.35 846B-32X-6W 94-100 301.579.860.512532-2.08 0.35 846B-33X-1W 100-107 303.8410.000.512554-1.65 0.35 846B-33X-2W 31-37 304.6410.050.512526-2.19 0.35 846B-33X-4W 144-150 308.7810.300.512527-2.17 0.35 846B-33X-6W 30-36 310.6310.420.512510-2.51 0.35 846B-34X-1W 140-146 313.8310.610.512488-2.93 0.35 846B-34X-3W 121-127 316.6410.780.512526-2.18 0.35 846B-34X-4W 111-117 318.0410.870.512521-2.28 0.35 846B-34X-7W 21-27 321.6411.090.512541-1.90 0.35 846B-36X-2W 128-134 334.5111.870.512491-2.88 0.35 846B-36X-3W 128-134 336.0111.960.512481-3.07 0.35 846B-37X-2W 93-99 343.7612.430.512519-2.33 0.35 846B-38X-4W 144-150 356.9813.230.512490-2.90 0.35 846B-40X-1W 121-127 371.5414.140.512446-3.75 0.35

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38 Table 4-2. Nd isotopes of Foss il Fish Teeth from ODP Site 998. Sample Depth (mbsf) Age (Ma) 143Nd/144Nd Nd(o) 2 998A-15H-1W 21-26 132.518.950.512300-6.60 0.35 998A-15H-3W 107-113 136.379.330.512323-6.15 0.35 998A-15H-5W 27-32 138.589.520.512320-6.27 0.35 998A-16H-1W 54-59 141.859.790.512379-5.06 0.35 998A-16H-3W 126-129 146.0510.140.512351-5.61 0.35 998A-16H-4W 32-37 146.6210.180.512396-4.73 0.35 998A-16H-4W 45-50 146.7710.190.512457-3.54 0.35 998A-16H-5W 25.5-30 148.1110.300.512378-5.08 0.35 998A-16H-6W 32-36 149.6510.460.512400-4.65 0.35 998A-16H-6W 125-130 150.5810.590.512491-2.88 0.35 998A-17H-1W 21-26 151.5310.730.512496-2.78 0.35 998A-17H-1W 32-37 151.6210.750.512545-1.82 0.35 998A-17H-1W 77-82 152.0810.820.512498-2.74 0.35 998A-17H-1W 105-110 152.3510.860.512466-3.36 0.35 998A-17H-2W 25-30 153.0510.970.512440-3.87 0.35 998A-17H-2W 54-60 153.3611.020.512476-3.17 0.35 998A-17H-2W 126-131 154.0611.130.512443-3.81 0.35 998A-17H-4W 55-60 156.3811.500.512574-1.26 0.35 998A-17H-5W 2-7 157.3811.660.512440-3.87 0.35 998A-17H-5W 134-139 158.6811.820.512491-2.88 0.35 998A-17H-6W 26-31 159.0911.870.512637-0.03 0.35 998A-17H-6W 81-87 159.6511.930.512594-0.87 0.35 998A-17H-CCW 2-7 160.6212.030.512626-0.24 0.35 998A-18X-1W 105-111 161.8512.170.512420-4.26 0.35 998A-18X-3W 32-36 164.1212.410.512457-3.54 0.35 998A-19X-1W 53-58 166.7512.700.512418-4.30 0.35 998A-19X-5W 24-28 172.4413.500.512445-3.77 0.35 998A-20X-2W 32-36 177.7214.050.512434-3.99 0.35

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39 Table 4-3. Nd isotopes of Foss il Fish Teeth from ODP Site 999. Sample Depth (mbsf) Age (Ma) 143Nd/144Nd Nd(o) 2 999A-28X-1W 18-23 248.918.980.512395-4.75 0.35 999A-28X-3W 32-36 252.049.100.512337-5.88 0.35 999A-28X-4W 84-88 254.069.180.512360-5.42 0.35 999A-28X-5W 55-59 255.279.220.512474-3.21 0.35 999A-29X-1W 72-76 259.149.380.512546-1.79 0.35 999A-29X-2W 51-57 260.449.520.512514-2.43 0.35 999A-29X-4W 25-29 263.179.830.512555-1.63 0.35 999A-29X-6W 5-10 265.9810.150.512417-4.31 0.35 999A-29X-6W 66-70 266.5810.220.512489-2.92 0.35 999A-29X-6W 104-109 266.9710.260.512428-4.09 0.35 999A-30X-1W 128-132 269.3010.450.512415-4.35 0.35 999A-30X-2W 3-8 269.5610.460.512473-3.22 0.35 999A-30X-3W 59-63.5 271.6110.560.512421-4.24 0.35 999A-30X-4W 8-14 272.6110.610.512506-2.58 0.35 999A-30X-5W 2-7 274.0510.690.512495-2.79 0.35 999A-30X-6W 105-110 276.5810.780.512634-0.07 0.35 999A-30X-7W 28-33 277.3110.800.512508-2.53 0.35 999A-31X-2W 34-38 279.4610.870.512628-0.19 0.35 999A-31X-3W 7-12 280.7010.910.512506-2.58 0.35 999A-31X-4W 53-59 282.6610.980.512494-2.80 0.35 999A-32X-1W 28-33 287.5111.140.512547-1.77 0.35 999A-32X-2W 90-94 289.6211.210.512598-0.78 0.35 999A-32X-6W 18-23 294.9111.390.512580-1.14 0.35 999A-32X-6W 79-84 295.5211.410.512472-3.25 0.35 999A-33X-2W 4-10 298.2711.500.512568-1.38 0.35 999A-33X-3W 4-8 299.7611.550.512568-1.37 0.35 999A-33X-4W 106-111 302.2911.630.512470-3.29 0.35 999A-33X-6W 65-69 304.8711.720.512455-3.56 0.35 999A-33X-CCW 13-18 305.9611.770.512501-2.67 0.35 999A-34X-2W 145-150 309.2812.010.512308-6.44 0.35 999A-34X-3W 63-67 309.9512.060.512486-2.96 0.35 999A-34X-6W 100-105 314.8312.410.512448-3.70 0.35 999A-34X-6W 118-122 315.0012.430.512447-3.72 0.35 999A-35X-3W 109-113 320.1112.800.512486-2.96 0.35 999A-35X-5W 54-59 322.5712.980.512503-2.63 0.35 999A-35X-7W 17-21 325.1913.170.512484-3.00 0.35 999A-37X-1W 15-19 335.3713.190.512513-2.44 0.35 999A-37X-2W 6-11 336.7913.420.512497-2.76 0.35 999A-38X-1W 55-60 345.3813.690.512470-3.29 0.35 999A-38X-1W 69-73 345.5113.700.512478-3.12 0.35 999A-38X-5W 55-60 351.3814.010.512359-5.45 0.35

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40 CHAPTER 5 DISCUSSION 5.1 The Source of Caribbean Basin Nd Values in the Middle/Late Miocene The Nd values within the Caribbean Basin extend to values that are more radiogenic than any known intermediate/deep water masses within the equatorial Atlantic region. A critical question is whether these values represent the true water mass signa ture or a diagenetic product. An obvious source of radiogenic Nd is Caribbean arc volcanism. During the time interval of this study, the Caribbean Basin was influen ced by volcanic ash deposition with an Nd value of ~+7 (Drummond et al., 1995). Abunda nt layers and disseminated ash are observed at site 998 (Yucatan Basin) and site 999 (Col ombian Basin) (Peter s et al., 2000). However, a plot of the low resolution ash MAR versus Nd for these sites illustrates that there is no correlation between intervals of abundant ash and sa mples with more radiogenic Nd values (Figure 5-1). Another possible diagenetic input would be sediment from the Magdalen a and Orinoco Rivers in South America that drain into the Caribbean Basi n. The Magdalena River sediment has an Nd value of -8.3 (Goldstein et al., 1984), while the Orinoco River sediment has an Nd value of ~-14 (Goldstein et al., 1997). Thus, these values are far too negative to have generated the radiogenic Nd values observed in the Caribbean Basin. Although the Nd values in the Caribbean are distinct from those in the Atlantic, they are very similar to values recorded in the Pacifi c today and during the Miocene (Ling et al., 1997; ONions et al., 1998; Frank et al ., 1999; Reynolds et al., 1999; va n de Flierdt et al., 2004). Values for Pacific intermediate waters in the Miocene range from -3.6 to -4.0 from 9.2 to 13.4 Ma in the western equatorial Pacific (FeMn crust D11-1, 11N, 161E, 1,870-1,690m; Ling et al., 1997), from 9.9 to 14.5 Ma in the cen tral equatorial Pacifi c (Fe-Mn crust CD29-2, 16N, 168W, 2,390-1,970m; Ling et al., 1997), and from -2.0 to -2.6 from 8.8 to 13.13

PAGE 41

41 Ma in the north Pacific (Fe-Mn crusts 13D27A and D4-13A, Kamchatka and Alaska, 1,500 and 2,100 m; van de Flierdt et al., 2004) (Figure 5-2). The distribution of Nd in modern water column profiles from the western north Pacific illustrates a similar range of values. Surface waters from 3 m in this region have an Nd value of -0.1, while deep waters at 4,481 m have an Nd value of -3.9 (Piepgras and Jacobsen, 1988). A second profile near a Fe-Mn crust studied by van de Flierdt et al. (2004) documents a similar range of Nd values with +0.3 at 30 m and -4.5 at 2,800m (Piepgras and Jacobsen, 1988). van de Flierd t et al. (2004) conclude d that in addition to becoming less radiogenic with depth, the Nd values in the Pacific become more radiogenic at progressively higher latitude s in the North Pacific. The correlation between values recorded in th e Caribbean and Pacific, plus associated shifts in stable isotope data (Figures 5-3 and 5-4) support the idea that the Nd values in the Caribbean Basin during the middle/late Miocene ar e dominated by a signature from the Pacific; indicating that throughf low in the CAS was predominantly from west to east. Benthic 13C values have been used as a proxy for deep ocean circulation based on the fact that 13C decrease along the pathway of the global conveyor (i.e ., Savin et al., 1981; Curry and Lohman, 1982; Kroopnick, 1985; Woodruff and Savi n, 1989; Broecker et al., 1990; Charles and Fairbanks, 1992); however, this proxy also re sponds to carbon cycling. Roth et al. (2000) showed that middle to late Miocene 13C values shifted from 0.1 to 1.4 in the Caribbean, and, like the Nd values, the 13C values became more variable throughout the crash interval (Figure 5-3 and 5-4). Charles and Fairbanks (1992) showed modern 13C values of intermediate water in the equatorial Pacific fall within the ra nge of <0 to 0.8, while intermediate water in the equa torial Atlantic have values >0.7; however, the distinction between the Pacific and Atlantic was more subtle during the Miocene (Wri ght and Miller, 1996; P oore et al., 2006).

PAGE 42

42 Nd isotopes provide a mechanism for deconvol ving the circulation and nutrient signals inherent in 13C. Piotrowski et al (2005) used plots of Nd and 13C in the Southern Ocean to illustrate that there are correlated shifts between the two systems, which they attributed to changes driven by circulation and water ma ss composition on long-term and millennial timescales. They also noted a lead/lag relations hip during glacial termin ations, indicating that changes in 13C, and therefore the carbon mass balan ce of the ocean, preceded changes in circulation as represented by Nd A similar comparison between Nd and 13C for the Caribbean sites illustrates a general co rrelation between the two record s, supporting the idea that the variations in Nd record changes in circulation rather th an ash diagenesis (Figures 5-3 and 5-4). The radiogenic Nd values observed at sites 998 a nd 999 do not support the original interpretation by Roth et al. (2000) that the wate rs filling the Caribbean during the middle to late Miocene were derived from AAIW or NAIW. Instead, the Nd values are similar to Pacific intermediate waters (Figure 5-2). This flow of Pacific water fr om west to east through the CAS is also predicted by several general ocean circulation models evaluating the effects of an open Isthmus of Panama (e.g., Mikolajewicz and Cr owley, 1997; Nisancioglu et al., 2003; Nof and Van Gorder, 2003; Prange and Schultz, 2004; Kloc ker et al., 2005; Schneider and Schmittner, 2006; Steph et al., 2006). Based on benthic foraminiferal assemblages, Duque-Caro (1990) sugge sted that initial uplift of the Isthmus of Panama to 2000 m occu rred between 15.9 to 15.1 Ma (ages adjusted to Shackleton et al., 1995a) and shoaling to ~1000 m (upper bathyal depths) occurred between 1210.2 Ma (ages adjusted to Shackleton et al., 1995a). Shoaling of the Isthmus of Panama to 1000 m resulted in the flow of Pacific waters through the CAS into the Caribbean basin in the model presented by Nisancioglu et al (2003). The flow of Pacific water into the Caribbean Basin

PAGE 43

43 agrees well with coccoli th and planktonic foraminiferal a ssemblages (Chiasson and DHondt, 2000; Kameo and Sato, 2000) during this time. Site 999 (Caribbean Basin) and site 844 (eastern equatorial Pacific) recorded identical assemb lages from 16.2-13.6 Ma, these assemblages began to diverge between 13.6-10.7 Ma, an d finally completely distinct assemblages were identified between 10.7-9.4 Ma (Kameo and Sato, 2000). B ecause coccoliths live w ithin the photic zone, the data suggest the CAS limited surface water exchange by ~10 Ma. Foraminiferal assemblages identified from site 999 also suggest the fl ow of Pacific water into the Caribbean (Chiasson and DHondt, 2000). Chiasson and DHondt (2000) identified temperate-latitude foraminiferal assemblages (Globoconellids) at site 999 until ~10.7 Ma, and interpreted their presence to represent an in flux of cool Pacific surface water, either the California or Peru Current system depending on the position of the ITCZ (Chiasson and DHondt, 2000). Flohn (1981) predicts a more north erly position of the ITCZ at this time (~10N) as a result of thermal asymmetry attributed to the diffe rences in ice sheet development between the northern and southern hemispheres. Due to the weaker pole-equator temperature gradient in the northern hemisphere the ITCZ sh ifts to a more northern position, which Steph et al. (2006) correlate to an increa se in the eastward flow of Paci fic waters into the Caribbean Basin; a prediction that is cons istent coccolith assemblages, foraminiferal assemblages, and Nd records during this time. 5.2 Circulation during the Caribbean Pr e-Crash and Pre-Crash Transition During the pre-crash and pre-crash transiti on there are subtle differences between the Nd values of the two Caribbean sites (Figure 4-2). Values at the southern site (site 999, Colombian Basin) increase during the pre-crash interval and reach values more radiogenic than those at Site 998 during the pre-crash transition. This shift to more radiogenic Nd values at site 999 coincides with a gradual shift to lower carbonate MARs, suggesting a progres sive influx of more corrosive

PAGE 44

44 and radiogenic intermediate Pa cific waters through the CAS pr ior to the carbonate crash. The Nd at site 998 remains relatively stable at a value similar to middle/late Miocene upperintermediate Pacific waters, but probably repr esent a mixture of Pacific and Atlantic surface waters because the Nicaragua Rise acted as a barrier to intermediate and deep water flow into the northern Caribbean Basin at this time. Faulting of the Nicaragua Rise led to the opening of the north/south oriented Pedro Channel and the northern part of the Walt on Basin (Cunningham, 1998). These channels provided a passage way for deep waters and ultim ately led to the development of the Caribbean Current, which flows from the southern Caribbean into the Gulf of Mexi co across the region of the Nicaragua Rise (Droxler et al., 1998). Prior to the connection between sites 998 and 999, slight differences in Nd at the two sites suggest that inte rmediate waters from the Pacific influenced site 999, while a mixture of Pacific and Atlantic surface waters influenced site 998 (Figure 5-5). Following the connection by ~12 Ma (Droxler et al., 1998), the range of values observed at sites 998 and 999 become more similar by ~11.8 Ma, al though there are still distinctions between the two sites. 5.3 The Caribbean Carbonate Crash At the beginning of the crash interval the Nd values at sites 998 and 999 diverge (Figure 56) with the values from 12.1 to 11.8 Ma at site 998 representing surface waters from the Pacific and the values at site 999 repr esenting either deeper waters fr om the Pacific or, more likely, a mixture of intermediate waters derived from th e Pacific (NPIW) and Atla ntic (AAIW) (Figures 4-2 and 5-2). During this time interval, site 998 s till appears to be separated from the southern Caribbean Basin by the Nicaragua Rise at an upper intermediate depth. The Nd values merge from 11.8 to 11.5 Ma and again from 10.7 to 10.18 Ma implying a connection between the northern and southern Caribbean si tes that can be attributed to foundering of the Nicaragua Rise

PAGE 45

45 (Droxler et al., 1992), which also l ead to the initiation of the Loop Current in the Gulf of Mexico (Mullins et al., 1987). The history of the foundering of the Nicaragua Rise has impo rtant implications for deep circulation in the Atlantic. Prior to the late early Miocene the Caribbean Current flowed through the Havana/Matanzas Channel in western Cuba (Itu rralde-Vincent et al.; 1996) into the Straits of Florida, bypassing the Gulf of Mexico (Droxler et al., 1998). The Havana/Matanzas Channel closed and the Pedro Channel opened during the late middle Miocene transition, redirecting the Caribbean Current into the Gulf of Mexico, th ereby initiating the Loop Current. This flow pattern effectively increases the residence ti me of the water in a high evaporation region, therefore the surface water exiti ng the Gulf of Mexico becomes more saline, leading to high salinities in the Gulf Stream and ultimately in th e surface waters of the North Atlantic. It is estimated that the Loop Current was initiated ~ 12-15 Ma (ages converted to Shackleton et al., 1995a) in the middle Miocene (M ullins et al., 1987). Throughout the carbonate crash interv al (12-10 Ma) the carbonate MARs, 13C, and Nd records show very erratic and la rge shifts at sites 998 and 999 with large decreases in carbonate MARs associated with shifts to more radiogenic Nd values. These large shifts may represent pulses of increased Pacific water inflow during carbonate dissolution ev ents, while a greater proportion of Atlantic inflow occurred dur ing the intervals w ith less radiogenic Nd values and enhanced carbonate preservation. The periods of increased Pacific inflow can also be linked to times of increased production of NCW (Figure 5-7 and 5-8). The interval of the carbonate crash, as defined by low carbonate MARs in the Ca ribbean Basin, correlates well with periods of increased NCW production from ~12.4 to 9.5 Ma as determined using 13C gradients between the Atlantic and Pacific. During times of NCW production 13C values in the North Atlantic are

PAGE 46

46 higher those in the Pacific. In contrast, there is very little difference between Atlantic and Pacific 13C values when the Southern Ocean is th e dominant source of deep water (Woodruff and Savin,1989; Wright and Miller 1996; Poore et al., 2006; ages ca librated to Shackleton et al., 1995a). Based on interbasin 13C gradients, Woodruff and Savi n (1989) argued for early, weak production of NCW from 14.5 to 11.4 Ma (ages update d to Shackleton et al., 1995a). After this time they proposed that strong SCW production do minated the deep Pacific and Atlantic in response to growth of the Anta rctic ice cap. The 11.4 Ma age (updated to Shackleton et al., 1995a) coincides with the sili ca switch (Keller and Barron, 1983) when the primary site of siliceous ooze deposition shifted fr om the Atlantic to the North P acific and Indian Oceans, which Woodruff and Savin (1989) attributed to increas ed NCW production Most studies agree that early NCW was produced during parts of the late middle Miocene, but the highest production of NCW in the Miocene occurred during the late Miocene (Blanc et al., 1980; Schnitker, 1980; Miller and Fairbanks, 1985; Woodruff and Sa vin, 1989; Wright et al., 1991, 1992, and 1996; Wei, 1995; Wei and Peleo-Alampay, 1997). Thomas and Via (2007) developed a Neogene Nd isotopic record at Walvis Ridge in the southeastern Atlantic Ocean to eval uate the onset of NCW production. The Nd values at site 1262 begin to decrease at ~13 Ma with a major decrease beginning at ~10.6 Ma. Thomas and Via (2007) interpret this shift to indicate greater proportions of NC W in the southeastern Atlantic Ocean. They argue that the ca rbonate crash in the Caribbean and equatorial Pacific was the result of the onset of deep water formation in th e Labrador Sea. The offset in the timing of the carbonate crash and the timi ng of the decrease in Nd values was probably a result of a low resolution Nd record (Thomas and Via, 2007). In the Caribbean, the Nd isotopic record agrees

PAGE 47

47 with enhanced NCW production determined by Wri ght and Miller (1996) a nd Poore et al. (2006) in which they suggested was controlled by the flow over North Atlantic sills Wright and Miller (1996) used 13C gradients between the Atla ntic, Pacific and Southern Ocean to calculate the %NCW production. Poore et al. (2006) updated the %NCW production calculations using new data a nd found that increased NCW production occurred at ~12 Ma, which is similar to the results Wright and Miller (1996) that suggest an increase at ~12.5 Ma. A comparison between this calcula ted %NCW production and the Nd record for Site 998 and 999 illustrates that, in general, increased producti on of NCW correlates with more radiogenic Nd values and decreased carbonate MARs (Figure 5-7 and 5-8). In other words, the carbonate crash events occur during times of enhanced NCW production. The overall correlation between increased Nd values and decreased carbonate MARs can therefore be attributed to the flow of corrosive intermediate and surface Pacific waters through the CAS into the Caribbean Basin during times of enhanced NCW producti on. This water would then flow north across the shallow Nicaragua Rise ultimately filling both basins (Colombian and Yucatan) with corrosive waters w ith radiogenic Nd isotopes. The one exception to this correlation occurs at ~12 Ma at Site 999 when increased NCW production and decreased car bonate MARs coincides with less radiogenic Nd values. One possible explanation is th at these less radiogenic Nd values during this early carbonate crash interval represent AAIW that flowed into th e southern Caribbean basin when NCW production rates were high. Thus, the southern basin wa s filled with a mixture of corrosive AAIW and NPIW, with AAIW dominating at ~12 Ma, wh ile the northern basin was filled with shallow/intermediate Pacific water (Figure 5-9). This idea is similar to the theory presented by Roth et al. (2000) that increased NCW was co mpensated by reduced NAIW and, therefore, more

PAGE 48

48 corrosive AAIW overflowed the sills and filled th e Caribbean Basin. As mentioned previously, the northern site (998) was still separated from the southern Caribbean by the Nicaragua Rise; therefore, this site records shallow/intermedia te Pacific throughflow observed in subsequent crash intervals instead of the deeper NAIW/AAIW mix. 5.4 Circulation during the Caribbean Post-Crash Transition and Post-Crash The Nd values at sites 998 and 999 diverge during the post-crash transition. Site 999 records a brief excursion to more radiogenic Nd values from 9.8 to 9.4 Ma, while site 998 continues to shift to less radiogenic values. The timing of these events correlates with a decrease in NCW production (Wright and Mi ller, 1996; Poore et al., 2006) (Figures 5-7 and 5-8), and a shift to light 13C after the Caribbean carbonate MAR recove red (Figures 5-3 and 5-4). The brief excursion at site 999 records mo re Pacific-like values, while S ite 998 continues to record an Atlantic/Pacific value with a decreasing Pacific component (Fi gure 5-10). The lack of a dissolution event associated with radiogenic Nd values at site 999 could have been the result of increased productivity and an associ ated increase in the carbonate rain rate in response to an increase in nutrient levels supp lied from old, Pacific waters. The 13C values recorded at site 999 (Roth, 1998) supports with this interpretation b ecause the values become lighter, indicating a more nutrient-rich water mass filling the southern Caribbean Basin (Figure 5-4). The fact that site 998 Nd values decrease while site 999 Nd values increase also suppo rts the idea that at least part of the 13C signal is a response to pr oductivity rather than water mass. An alternative scenario is that the entire Caribbean was filled with more Atlantic sourced water (i.e. NAIW) as a result of the decreasing produc tion of NCW, but site 999 conti nued to record more radiogenic Nd values because of its proximal location to th e CAS. The mixture of upper NPIW, Pacific surface waters, and NAIW at this site would account for the combination of enhanced carbonate preservation and more radiogenic Nd values. The continual decrease in Nd values at site 998

PAGE 49

49 during this time suggests that th e mixture observed at site 999 combined with a progressively increasing fraction of Atlantic waters before circulating into the northern basin. Gradually decreasing Nd values during the post-crash tran sition and post-crash at site 998 and post-crash at site 999 highlight the gradual reduction of Pacific thro ughflow coincident with the shoaling of the Isthmus of Panama and the fo undering of the Nicaragua Rise. Frank et al. (1999) and Reynolds et al. (1999) proposed a decrease in Paci fic throughflow entering the Florida Straits via the Loop Curre nt beginning at ~8.5 Ma based on data from Fe-Mn crusts in the equatorial Pacific and Florid a Straits. Data from sites 998 a nd 999 illustrate that decreasing throughflow began at ~10.7 Ma. It is impossible to determine whether the Atlantic source at this time was NAIW or AAIW because the percentage of Pacific versus Atlantic inflow is unknown. 5.5 The Pacific Carbonate Crash Shoaling of the Isthmus of Panama and the s ubsequent production of NCW also affected circulation patterns in the Paci fic Ocean and contributed to the middle Miocene carbonate crash in the eastern equatorial Pacific, although this ev ent at site 846 lags th e crash in the Caribbean Basin. The idea is that enhanced NCW production resulted in a greater contribution of NCW to Circumpolar Water (CPW), thereby lengthening th e pathway of deep water entering the Pacific and resulting in older, more corrosive deep wate rs. In todays ocean much of the Pacific deep water flows southward as either NPIW or PC W (Mix, Tiedemann, Blum et al., 2003; Figure 511). The formation of NPIW occurs with relati vely little interaction with the atmosphere, causing the water mass to remain depleted in oxygen, high in CO2 (Talley, 1993), and have the highest nutrient concentrati on in the Pacific (Figure 5-11) Enhanced global conveyor circulation associated with NC W production would therefore resu lt in more corrosive NPIW, PCW, and North Pacific Surf ace and increased flow of that water toward the south.

PAGE 50

50 The Nd shift toward slightly more radiogenic values during the carbona te crash interval at site 846 (Figure 4-2) supports this link between NCW production and the composition of Pacific waters. More radiogenic Nd values and decreased car bonate MARs would both result from the expansion of corrosive NPIW and PCW southward in res ponse to NCW production. The timing of dissolution events recorded at site s in the eastern equatorial Pacific documents the development and introduction of this more co rrosive water mass from the north. The most northerly site examined in the eastern equatori al Pacific (Leg 138 site 845; 3,715 m) experienced a large decrease in carbonate MARs beginning at approximately 12 Ma. Carbonate dissolution also occurred between ~12 to 9 Ma at an interm ediate water depth site (Leg 202 site 1241 on the Coccos Ridge; 2,027 m) at the same latitude as the CAS (Mix, Tiedemann, Blum, et al., 2003). Sites 844 (3,415 m) and 846 (3,307 m) on the other hand, which are further south than site 845, did not begin to experience carbonate dissolution until ~11.5 Ma. Thus, the introduction of corrosive waters coming from the north Pacific pr ogressed from the more northerly sites to more southerly sites. The carbonate MAR and Nd records for site 846 suggest that this site does not represent the endmember of the intermediate depth wate r flowing into the Caribbean Basin. Instead, it monitors the water mass that flowed south of th e CAS into the Peru Basin. On the other hand, site 1241 located on the Coccos Ridge across from th e CAS in the Pacific at intermediate depth might be a better site to mon itor the Pacific intermediate depth throughflow because of its location and depth.

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51 Ash MAR Age (Ma) 89101112131415Nd -6 -4 -2 0 Site 999 89101112131415 Nd -6 -4 -2 0 Site 998 0.0 0.2 0.4 0.6 Ash MAR 0.0 0.2 0.4 0.6 Figure 5-1. Nd values and ash MARs (Peters et al., 2000) from sites 999 and 998 in the Caribbean Basin spanning from 8 to 14.5 Ma.

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52 Figure 5-2. Nd values from sites 998 and 999 in the Caribbean Basin, site 846 in the eastern equatorial Pacific, Fe-Mn crusts from the North Atlantic, Straits of Florida, North Pacific, central equatorial Paci fic (Burton et al., 1997, 1999 (BM1969.05); ONions et al., 1998 (ALV 539)), Straits of Florida (Reynolds et al., 1999 (BM1963.897)), North Pacific (van de F lierdt et al., 2004 (D4-13A, 13D-27A)), central equatorial Pacific (Ling et al ., 1997 (VA13-2, CD29-2, D11-1); Frank et al., 1999 (GMAT 14D)). Nd values from sites 998 a nd 999 are very similar to Pacific values from 14 to ~10 Ma. Fo llowing the carbonate crash they approach values recorded at BM1963.897 in the Straits of Florida. Age (Ma) 0123456789101112131415 Nd -12 -10 -8 -6 -4 -2 0 Site 999 (2,897m) Site 998 (3,179m) Site 846 (3,296m) BM1969.05 (1,829m) ALV 539 (2,665m) D11-1 (1,870 1690m) CD29-2 (2,390 1,970m) VA13-2 (4,830m) GMAT 14D (4,000 3,400m) D4-13A (Alaska) (2,100m) 13D-27A (Kamchatka) (1,800 1,500m) BM1963.897 (Straits of Florida) (850m)

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53 13C 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 13C Site 998Age (Ma) 9.09.510.010.511.011.512.012.513.013.514.0 Nd -6 -4 -2 0 Nd Figure 5-3. Nd and 13C values (Roth, 1998) from site 998.

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54 91011121314 13C 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 13C Site 999Age (Ma) 91011121314 Nd -6 -5 -4 -3 -2 -1 0 Nd Figure 5-4. Nd and 13C values (Roth, 1998) from site 999.

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55 Figure 5-5. Flow patterns of Atlantic (green) and Pacific (blue) waters during the PreCrash/Pre-Crash Transition intervals. Solid lines represent flow of intermediate water and dashed lines represent upper/sur face flow. Simplified reconstruction of the Caribbean Basin (after Pindell (1994) and modified from Roth et al. (2000)).

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56 Age (Ma) 89101112131415 Nd -7 -6 -5 -4 -3 -2 -1 0 Site 999 (Colombian Basin) Site 998 (Yucatan Basin) Figure 5-6. Ndvalues from sites 998 and 999 in the Ca ribbean Basin spanning from 8 to 14.5 Ma.

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57 Figure 5-7. Nd values from site 998, carbonate MAR (R oth et al., 2000), and %NCW (Wright and Miller, 1996). NCW 0 20 40 60 80 100 %NCW Age (Ma) 9.09.510.010.511.011.512.012.513.013.514.0 Nd -6 -4 -2 0 Nd Carbonate MAR 0.0 0.2 0.4 0.6 0.8 1.0 CaCO 3 MAR Site 998 Yucatan Basin

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58 Age (Ma) 9.09.510.010.511.011.512.012.513.013.514.0 Nd -6 -4 -2 0 Nd Site 999 Yucatan Basin CaCO3 MAR 0.0 0.5 1.0 1.5 2.0 CaCO 3 MAR %NCW 0 20 40 60 80 100 %NCW Figure 5-8. Nd values from site 999, carbonate MAR (R oth et al., 2000), and %NCW (Wright and Miller, 1996).

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59 Figure 5-9. Flow patterns of A tlantic (green) and Pacific (blu e) waters during the Carbonate Crash interval. Solid lines represent flow of intermediate water and dashed lines represent upper/surface flow. Simplified reconstruction of the Caribbean Basin (after Pindell (1994) and modifi ed from Roth et al. (2000)).

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60 Figure 5-10. Flow patterns of Atlantic (green) and Pacific (b lue) waters during the Post-Crash Transition/Post-Crash intervals. Solid lin es represent flow of intermediate water and dashed lines represent upper/surface fl ow. Simplified reconstruction of the Caribbean Basin (after Pindell (1994) and modified from Roth et al. (2000)).

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61 Figure 5-11. Dissolved oxygen profile from th e Pacific (modified after Mix, Tiedemann, Blum, et al., 2003). White box indicates the water mass which would flow through the CAS after the Isthmus of Panama shoaled to 1000 m. Water entering the Caribbean Basin through the CAS

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62 CHAPTER 6 CONCLUSIONS Fossil fish teeth were analyzed from sites 998 and 999 in the Caribbean Basin and site 846 in the eastern equatorial Pacific to study ocean ci rculation using Nd isotopes during the middle to late Miocene carbonate crash. The radiogenic Nd values recorded in the Caribbean Basin range from 0 to -6.6 and are distinct from values re ported in the Atlantic. The lack of correlation between Nd and ash deposition in the Caribbean Basi n and the close correlation to values recorded in the Pacific during the Miocene argu e that these radiogenic values represent CAS throughflow rather than ash altera tion. West to east flow thro ugh the CAS is consistent with general ocean circulation models and 13C data. In the Caribbean Basin, more radiogenic Nd values correlate with intervals of decreased carbonate MARs. The gradual decrease in carbonate MARs and increase in Nd values beginning at ~14 Ma at site 999 indicates the gradual introducti on of a more corrosive intermediate water mass flowing into the southern Caribbean Basin from the Pacific, while the northern Caribbean Basin site (site 998) Nd values and carbonate MARs remain ed relatively stable with values representing a mixture of Pacific and Atlant ic surface waters. During the carbonate crash interval (12-10 Ma) the Nd values are highly variable and peak at 0 Nd units, indicating pulses of Pacific waters entering the Caribbean Basin. This inflow of Pacific waters into Caribbean Basin through the CAS is predicted by several GCMs l ooking at the affects of CAS sill depths, NADW production, and the location of the ITCZ. Although sites 998 and 999 record similar Nd values there are distinct differences between the two records that can be attributed to their locations relative to the CAS, as well as the extent of communication across the Nicaragua Ri se. After the carbonate crash, the Nd values in the Caribbean gradually shift to less radiogenic values indicating a gradual d ecline in the amount of

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63 Pacific water entering the Caribb ean Basin, coincident with the shoaling of the Isthmus of Panama. The increased proportion of Atlantic wa ters in the water mass exiting the Caribbean and flowing through the Straits of Flor ida is also documented by decreasing Nd values in an FeMn crust from the Straits of Florida (Reynolds et al., 1999). Site 846 in the Pacific shows a similar pa ttern to the Caribbean Basin in which the Nd values shift to more radiogenic values during times of decreased carbonate MARs. The initiation of the Pacific carbonate crash app ears to be the result of the continued shoaling of the Isthmus of Panama and enhanced production of NCW. The increase in the Nd to more NPIW values, and the southward progression of low carbonate MARs from sites 845 and 1251 to sites 844 and 846 farther south support the idea that older, more corrosive NPIW and PCW flowed southward in the eastern equatorial Pacific, causing the carbonate crash in this region. Wright and Miller (1996) and Poore et al (2006) suggest increas ed NCW production was the result of the subsidence of th e Greenland-Scotland Ridge in the North Atlantic. These results also indicate that increased NC W production coincides with shoa ling of the Isthmus of Panama, foundering of the Nicaragua Rise, and the carbon ate crash in the Caribbean region. In the Caribbean region, foundering of th e Nicaragua Rise and the development of the Loop Current increased the residence time of waters in the Gulf of Mexico resulting in more saline outflow to the North Atlantic, further enhancing NCW pr oduction. In addition, e nhanced production of NCW affected the age of CDW fl owing into the Pacific Ocean, resulting in more corrosive NPIW and PCW returning southward, producing a north to south progression of carbonate dissolution from the eastern equatorial Pacifi c region and Caribbean Basin to the southern eastern equatorial Pacific region during the middle/late Miocene carbonate crash.

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64 LIST OF REFERENCES Abouchami W., Goldstein S.L .., Galer S.J.G., Eisenhauer A., and Mangini A. (1997) Secular changes of lead and neodymium in c entral Pacific seawater recorded by a Fe-Mn crust. Geochim. Cosmochim. Acta 61 (18), 3957-3974. Albarede F., and Goldstein S.L. (1992) Worl d map of Nd isotopes in sea-floor ferromanganese deposits. Geology 20 761-763. Albarede F., Goldstein S. L., and Dautel D. (1997) 143Nd/144Nd of Mn nodules from the Southern Ocean and Indian oceans, the global oceanic Nd budget, and their bearings on the deep ocean circul ation during t he Quaternary. Geochim. Cosmochim. Acta 61 1277-1291. Austin J. A., Schlager W., Palmer A.A ., and ODP Leg 101 Scientific Party. (1988) Proceedings of the Ocean Dr illing Program, Initial Reports (Part A). Ocean Drilling Program, Colle ge Station, Texas. Belshaw N. S., Freedman P.A.., ONions R.K.., Frank M., and Guo Y. (1998) A new variable dispersion double-focusing plas ma mass spectrometer with performance illustrated for Pb isotopes. International Journal of Mass Spectrometry 181 5158. Bertram C. J., and Elderfield H. (1993) The geochemical balance of the rare earth elements and Nd isotopes in the oceans. Geochim. Cosmochim. Acta 57 19571986. Bird D., Hall S. A., Casey J.F., and Millega n P.S. (1993) Interpretation of magnetic anomalies over the Grenada Basin. Tectonics 12 1267-1279. Blanc P.-L.., Rabussier D., Vergnaud-Grazzi ni C., and Duplessy J.C. (1980) North Atlantic Deep Water formed by the later middle Miocene. Nature 283 553-555. Boyle E. A. (1981) Cadmium, Zinc, Copper and Barium in foraminifera tests. Earth Planet. Sci. Lett. 53 11-35. Boyle E. A., and Kiegwin L.D. (1985) Compar ison of Atlantic and Pacific paleochemical records for the past 215,000 y: Changes in deep ocean circulation and chemical inventories. Earth Planet. Sci. Lett. 76 135-150. Broecker W.S., and Peng T.-H. (1982) Tracers in the Sea Eldigio Press. Broecker W. S., Bond G., Klaus M., Bonani G.A ., and Wolfli W. (1990) A salt oscillator in the glacial Atlantic? 1. The concept. Paleoceanography 5 469-477.

PAGE 65

65 Buckry D. (1973) Low-latitude coccolith bios tratigraphic zonation. In: Edgar N.T., Saunders J.B., et al. (Ed.), Init. Repts. DSDP 15 U.S. Govt. Printing Office, Washington. 685-703 Burton K. W., Ling H.-F., and ONions R.K. (1997) Closure of the Central American Isthmus and its effect on deep-water formation in the north Atlantic. Nature 386 382-385. Burton K.W., Lee D.-C., Christensen J.N., Halli day A.N., and Hein J.R. (1999) Actual timing of neodymium isotopic variations re corded by Fe-Mn crusts in the western North Atlantic. Earth Planet. Sci. Lett. 171 149-156. Charles C.D., and Fairbanks R.G. (1992) Ev idence from Southern Ocean sediments for the effect of North Atlantic deep-water flux on climate. Nature 355 416-419. Chiasson W.P., and D'Hondt S.L.. ( 2000) Neogene Planktonic Foraminifer Biostratigraphy at Site 999, Wester n Caribbean Sea. In: Leckie, R. M., Siquardssom, H., Acton, G.D., and Draper, G. (Ed.), Proc. ODP, Sci. Res. 165 Ocean Drilling Program, College Station, TX. Coates A.G., Jackson J.B., Collins L.S., Croni n T.M., Dowsett H.J., Bybell L.M., Jung P., and Obando J.A. (1992) Closure of t he Isthmus of Panama: the near-shore marine record of Costa Rica and Western Panama. Geol. Soc. Am. Bull. 104 814-828. Cunningham A. D. (1998) N eogene Evolution of the Pedro Channel Carbonate System, Northern Nicaragua Rise [Ph.D. thesis], Rice University. Curry W.B., and Lohmann G.P. (1982) Carbon is otopic changes in benthic foraminifera from the western South At lantic: Reconstruction of glacial abyssal circulation patterns Quaternary Research 18 218-235. Denny W.M., Austin J.A., and Buffler R.T. (1994) Seismic stratigraphy and geologic history of mid-Cretaceous through Cenozoi c rocks, Southern Straits of Florida. AAPG Bulletin 78 461-487. DePaolo D.J., and Wasserburg, G.J. (1976) Nd isotopic variations and petrogenetic models. Geophys. Res. Lett. 3 249-252. Droxler A.W., Cunningham A. D., Hine A.C., Hallock P., Duncan D., Rosencrantz E., Buffler R., and Robinson E. (1992) Late Mi ddle (?) Miocene segmentation of an Eocene-early Miocene carbonate m egabank on the northern Nicaragua Rise. EOS, Transactions (supplement) 73 Droxler A.W., Burke K.C., Cunningham A.D., Hine A.C., Rosencrantz E., Duncan D.S., Hallock P., and Robinson E. (1998) Caribbe an constraints on circulation between

PAGE 66

66 Atlantic and Pacific Oceans over the past 40 million years. In: Cr owley, T. J., and K.C. Burke (Ed.), Tectonic Boundary Conditions for Climate Reconstructions Oxford Univ. Press, New York. Drummond M.S., Bordelon M., De Boer J.Z.., Defant M.J., Bellon H., and Feigenson M.D. (1995) Igneous petrogenes is and tectonic settin of plutonic and volcanic rocks of the Cordillera De Talamanca, Costa Rica-Panama, Central American Arc. American Journal of Science 195 875-919. Duque-Caro H. (1990) Neogene stra tigraphy, paleoceanography and paleobiogeography in northwe st South America and the evolution of the Panama Seaway. Palaeogeogr., Palaeoclim., Palaeoecol. 77 203-234. Elderfield H., and Greaves M.J. (1982) T he rare earth elements in seawater. Nature 296 214-219. Elderfield H., and Pagett R. (1986) Rare earth elements in icthyoliths: Variations with redox conditions and depositional environments. Sci. Total Environ. 49 175-197. Elderfield H. (1988) The oceanic chemis try of the rare earth elements. Philos. Trans. R. Soc. London Ser. A (325), 105-126. Exon N., Kennett J.P., and Scientific Shipboard Party. (2002) Drilli ng reveals climatic consequences of Tasmanian Gateway opening. EOS, Transactions AGU 83 253-259. Farrell J.D., Raffi I., Janecek T.R., Murray D.W., Levitan M., Dadey K.A., Emeis K.-C., Lyle M., Flores J. A., and Hovan S. (1995) Late Neog ene sedimentation patterns in the eastern equatorial Pacific Ocean. In Proceeding ODP, Scientific Results Vol. 135 (ed. L. A. M. N.G. Pisias, and T.R. Janecek), pp. 717-756. Frank M., and O'Nions R.K. (1998) Source s of Pb for the Indian Ocean ferromanganese crusts: a record of Himalayan erosion? Earth Planet. Sci. Lett. 158 121-130. Flohn H. (1981) A hemispheric circulati on assymetry during late Tertiary. Geol. Rundsch. 70 725-736. Frank M., Reynolds B.C., and O' Nions R.K. (1999) Nd and Pb isotopes in Atlantic and Pacific water masses before and after closure of the Panama gateway. Geology 27 1147-1150. Frank M., Whiteley N., Kasten S., Hein J.R. and O'Nions R.K. (20 02) North Atlantic Deep Water export to the Southern Ocean over the past 14 Myr: Evidence from Nd and Pb isotopes in ferromanganese crusts. Paleoceanography 17 (doi:10.1029/2000PA000606).

PAGE 67

67 Frank M. (2002) Radiogenic isotopes: trac ers of past ocean circulation and erosional input. Reviews in Geophysics 40 1-38. Frank M., van de Flierdt T., Halliday A.N ., Kubik P.W., Hattendorf B., and Gunther D. (2003) Evolution of deepwat er mixing and weathering inputs in the central Atlantic Ocean over the past 33 Myr. Paleoceanography 18 German C.R., Klinkhammer G.P., Edmond J.M. Mitra A., and Elderfield H. (1990) Hydrothermal scavenging of rareearth elements in the ocean. Nature 345 516518. Goldstein S.L., O'nions R.K ., and Hamilton P.J. (1984) A Sm-Nd isotopic study of atmospheric dusts and particulate s from major river systems. Earth Planet. Sci. Lett. 70 221-236. Goldstein S.J., and Jacobsen S.B. (1988) Rare earth elements in river waters. Earth Planet. Sci. Lett. 89 35-47. Goldstein S.L., Arndt N.T., and Stallard R.F. (1997) The history of a continent from U-Pb ages of zircons from Orinoco River s and and Sm-Nd isotopes in Orinoco basin river sediments. Chemical Geology 138 271-186. Goldstein S.L., and Hemming S.R. (2003) L ong-lived isotopic tracers in oceanography, paleoceanography and ice sheet dynamics. In Treatise on Geochemistry Vol. 6 (ed. H. Elderfield), pp. 453-489. Elsevier. Gomberg D. (1974) Geology of the Portales Terrace. Florida Science 37 15. Greaves M.J., Statham P.J., and Elderfield H. (1994) Rare ear th element mobilization from marine atmospheric dust into seawater. Marine Chemistry 46 255-260. Haddad G.A. (1994) Calcium carbonate disso lution patterns at intermediate water depths of the Tropical oceans during t he Quaternary [Ph.D. thesis], Rice University. Haddad G.A., and Droxler A.W. (1996) Metastable CaCO3 dissolution at intermediate water depths of the Caribbean and wester n North Atlantic: Implications for intermediate water circulati on during the past 200,000 years. Paleoceanography 11 701-716. Haug G.H., and Tiedemann R. (1998) Effect of the formation of the Isthmus of Panama on Atlantic Ocean ther mohaline circulation. Nature 393 673-676. Henry F., Jeandel C., and Minster J, -F. (19 94) Particulate and dissolved Nd in the western Mediterranean Sea: Sources, fates and budget. Marine Chemistry 45 283-305.

PAGE 68

68 Iturralde-Vinent M., Hubbell G., and Roja s R. (1996) Catalogue of Cuban fossil Elasmobranchii (Paleocene to Pliocene) and paleogeographic implications of their Lower to Midddle Miocene occurrence. J. Geological Soc. Jamaica 31 7-21. Jeandel C. (1993) Concentration and isotopic compositions of Nd in the South Atlantic Ocean. Earth Planet. Sci. Lett. 117 581-591. Jeandel C., Bishop J.K., and Zindler A. ( 1995) Exchange of Nd and its isotopes between seawater small and large par ticles in the Sargasso Sea. Geochim. Cosmochim. Acta 59 535-547. Jeandel C., Thouron D., and Fieux M. (1998) Concentrations and isotopic compositions of neodymium in the eastern I ndian Ocean and Indonesian Straits. Geochim. Cosmochim. Acta 62 2597-2607. Johns W.E., Townsend T.L., Fratantoni D.M ., and Wilson W.D. (2002 ) On the Atlantic inflow to the Caribbean Sea. Deep-Sea Research I 49 211-243. Kameo K., and Bralower T.J. (2000) Neogene nannofossil bios tratigraphy of Sites 998, 999, and 1000. In Proc. ODP, Sci. Res. Vol. 165 (ed. R. M. Leckie, Siquardssom, H., Acton, G. D., and Draper, G.), pp. 3-18. Kameo K., and Sato T. (2000) Biogeography of Neogene calcareous nannofossils in the Caribbean and the eastern equatorial Pacificfloral response to the emergence of the Isthmus of Panama. Marine Micropaleontology 39 201-218. Keigwin L.D. (1982) Isotopi c Paleoceanography of the Ca ribbean and East Pacific: Role of Panama Uplift in Late Neogene Time. Science 217 350-353. Keller G., and Barron J.A. (1983) Paleocea nographic implications of Miocene deep-sea hiatuses. Geol. Soc. Am. Bull. 94 590-613. Keller G., Zenker C.E., and Stone S.M. (1989) Late Neogene history of the PacificCaribbean gateway. Journal of South American Earth Science 2 73-108. Kennett J.P., Houtz R.E., Andrews P.B., Edwa rds A.R., Gostin V.A., Hajos M., Hampton M.A., Jenkins D.G., Margolis S.V., Ovens hine A.T., and Perch-Nielsen K. (1974) Development of the Cir cum-Antarctic Current. Science 18 144-147. Kennett J.P. (1977) Cenozoic evolution of An tarctic Glaciation, the Circum-Antarctic Ocean and their impact on global paleoceanography. Journal of Geophysical Research 82 3843-3860. King T.A., Ellis Jr. W.G., Murray D.W., Shackleton N.J., and Harris S. (1997)

PAGE 69

69 Miocene evolution of carbonate sedimentati on at the Ceara Rise: a multivariate date/proxy approach. In Proc. ODP, Scientific Results Vol. 154 (ed. N. J. Shackleton, Curray, W.B., Richter, C., and Bralower, T.J.), pp. 349-366. Klocker A., Prange M., and Schulz M. (2005) Testing the influence of the Central American Seaway on orbitally forc ed Northern Hemisphere glaciation. Geophys. Res. Lett. 32 L03703. Kroopnick P. M. (1985) The distribution of 13C in the world oceans. Deep Sea Research 32 57-84. Lacan F., and Jeandel C. (2001) Tracing Pa pua New Guinea imprint on the central Equatorial Pacific Ocean using neodymium isotopic compositions and Rare Earth Element patterns. Earth Planet. Sci. Lett. 186 497-512. Le J., Mix A.C., and Shackleton N.J. (1995) Late Quaternary paleoceanography in the eastern equatorial Pacific Ocean from plank tonic foraminifers: a high-resolution record from Site 846. In: Pisias, N. G. Mayer L.A., Janecek T.R., Palmer-Julson A., and van Andel T.H. (Ed.), Proc. ODP Sci. Res. 138 Ocean Drilling Program, College Station, TX. Lewis J.F., and Draper G. (1990) Geology and tectonic evolution of the northern Caribbean margin. In: Dengo, G., and J.E. Case (Ed.), The Geology of North America The Geological Society of America, Boulder, Colo. Ling H.-F., Burton K.W., O'Nions R.K., Kamber B.S., von Blankenburg F., Gibb A.J.,and Hein J.R. (1997) Evolution of Nd and Pb isotopes in Central Pacific seawater from ferromanganese crusts. Earth Planet. Sci. Lett. 146 1-12. Lyle M., Dadey K.A., and FarrellJ.W. (1995) The late Miocene (11-8 Ma) eastern Pacific carbonate crash: Evidence for r eorganization of deep-water circulation by the closure of the Panama Gateway. In Proceedings ODP, Scientific Results Vol. 138 (ed. L. A. M. N.G. Pisi as, and T.R. Janecek), pp. 821-838. Martin E.E., and Haley B.A. (2000) Fossil fi sh teeth as proxies for seawater Sr and Nd isotopes. Geochim. Cosmochim. Acta 64 835-847. Martin E.E., and Scher H. (2004) Preservation of seawater Sr and Nd in fossil fish teeth: bad news and good news. Earth Planet. Sci. Lett. 220 25-39. Martin E.E., Macdougall J.D., Herbert T.D., Paytan A., and Kastner M. (1995) Sr and Nd isotopic analyses of marine barite separates. Geochim. Cosmochim. Acta 59 1353-1361. Martini E. (1971) Standard Tertiary and Qu aternary calcareous na nnoplankton zonation. In: Farinacci, A. (Ed.), Proc. 2nd Planktonic Conf. Roma Rome.

PAGE 70

70 Mayer L., Pisias N., Janecek T., et al. (1992) Proceeding of the Oc ean Drilling Program, Initial Reports Ocean Drilling Program, College Station, TX. Michard A.., Albarede F., Michard G., Minste r J.F., and Charlou J.L. (1983) Rare-earth elemetns and uranium in high-temperatur e solutions from East Pacific Rise hydrothermal vent field (13-degrees-N). Nature 303 795-797. Mikolajewicz U., and Crowley T.J. (1997) Response of a coupled ocean/energy balance model to restricted flow th rough the Central American isthmus. Paleoceanography 12 429-441. Miller K.G., and Fairbanks R.G. (1985) Oli gocene to Miocene carbon isotope cycles and abyssal circulation changes. In: Sundquis t, E. T., and W.S. Broecker (Ed.), The Carbon Cycle and Atmospheric CO2: Natu ral variations Archean to Present Geophys. Monogr. Ser., AGU, Washington, DC. Mix A.C., Tiedemann R., Bl um P., et al. (2003) Proceedings of t he Ocean Drilling Program, Initial Reports Ocean Drilling Program, College Station, TX. Moore Jr. T.C., Shackleton N. J., and Pisias N.G. (1993) Pa leoceanography and the diachrony of radiolari an events in the eastern equatorial Pacific. Paleoceanography 8 567-586. Mller-Karger F.E., McClain C.R., Fisher T. R., Esaias W.E., and Varela R. (1989) Pigment distribution in the Caribbean Sea: Observations from space. Prog. Oceanogr. 23 23-64. Mullins H.T., and Neumann A.C. (1979) G eology of the Miami Terrace and its paleoceanographic implications. Marine Geology 30 205-232. Mullins H.T., Neumann A.C., Wilber R.J., Hine A.C., and Chinburg S.J. (1980) Carbonate sediment drifts in t he northern Straits of Florida. AAPG Bulletin 64 1701-1717. Mullins H.T., Gardulski A.F., Wise S.W. and Applegate J. ( 1987) Middle Miocene oceanographic event in the eastern Gulf of Mexico: Implications for seismic stratigraphic succession and Loop Curr ent/Gulf Stream circulation. Geol. Soc. Am. Bull. 98 702-713. Nisancioglu K.H., Raymo M.E., and Stone P. H. (2003) Reorganization of Miocene deep water circulation in response to the shoaling of the Central American Seaway. Paleoceanography 18 (1), 1006, doi:10.1029/2002PA000767. Nof D., and van Gorder S. (2003) Did an open Panama Isthmus correspond to an invasion of Pacific water into the Atlantic? J. Phys. Oceanogr. 33 1324-1336.

PAGE 71

71 O'Nions R.K., Frank M., von Blanckenburg F ., and Ling H.-F. (1998) Secular variation of Nd and Pb isotopes in ferromanganese cr usts from the Atlantic, Indian and Pacific Oceans. Earth Planet. Sci. Lett. 155 15-28. Peters J.L., Murray R.W., Sparks J.W., and Coleman D.S. (200 0) Terrigenous matter and dispersed ash in sediment from the Ca ribbean Sea: results from Leg 165. In: R.M. Leckie, S., H., Acton, G.D., and Draper, G. (Ed.), Proceeding of the Ocean Drilling Program, Scientific Results Ocean Drilling Program, College Station, TX. Piepgras D.J., and Wasserbur g G.J. (1982) Isotopic com position of neodymium in waters from the Drake Passage. Science 217 207-214. Piepgras D.J., and Wasserbur g G.J. (1985) Str ontium and neodymium isotopes in hot springs on the East Pacific Rise and Guaymas Basin. Earth Planet. Sci. Lett. 72 341-356. Piepgras D.J., and Wasserbur g G.J. (1987) Rare earth element transport in the western North Atlantic inferred from Nd isotopic observations. Geochim. Cosmochim. Acta 51 1257-1271. Piepgras D.J., and Jacobsen S. B. (1988) The isotopic com position of neodymium in the North Pacific. Geochim. Cosmochim. Acta 52 1373-1381. Pinet B., Lajat D., Le Quellec P., and Bouyss e P. (1985) Structure of Aves Ridge and Grenada Basin from multichannel se ismic data. In: Mascle, A. (Ed.), Geodynamique des Caraibes Editions Technip., Paris. Piotrowski A. M., Goldstei n S.L., Hemming S.R., and Fairb anks R.G. (2005) Temporal Relationships of Carbon Cycling and Ocean Circulation at Glacial Boundaries. Science Philander S.G.H., and Pacanowski R.C. (1 986) A model of the season cycle in the tropical Atlantic. J. Geophys. Res. 91 14192-14206. Poore H.R., Samworth R., White N.J., Jones S.M., and McCave I.N. (2006) Neogene overflow of Northern Component Wate r at teh Greenland-Scotland Ridge. Geochemistry, Geophysics, Geosystems 7 Popenoe P. (1985) Cenozoic depos itional and structural hist ory of the North Carolina margin from seismic stratigraphic analyses. In: Poag, C. W. (Ed.), Geologic evolution of the United States Atlantic margin Van Nostrand Reinhold, New York.

PAGE 72

72 Prange M., and Schulz M. (2004) A coastal upwelli ng seesaw in the Atlantic Ocean as a result of the closure of t he Central American Seaway. Geophys. Res. Lett. 31 L17207. Puteanus D., and Halbach P. (1988) Correlation of Co concentration and growth rate: A method for age determination of ferromanganese crusts. Chemical Geology 69 73-85. Raffi I., and Flores J.-A. (1995) Pleistocene through Miocene calcareous nannofossils from eastern equatorial Pacific Ocean (Leg 138). In Proc. ODP, Sci. Res. Vol. 138 (ed. N.G. Pisias, L.A. Maye r, and T.R. Janec ek), pp. 233-286. Reynolds B.C., Frank M., and O'Nions R.K. (1999) Ndand Pbisotope time series from Atlantic ferromanganese crusts: imp lications for changes in provenance and paleocirculation over the last 8 Myr. Earth Planet. Sci. Lett. 173 381-396. Roth J.M. (1998) The Caribbean carbonate crash at the middle to late Miocene transition and the establishment of the modern global thermohaline circulation [M.S. thesis], Rice University. Roth J.M., Droxler A.W., and Kameo K. (20 00) The Caribbean carbonate crash at the middle to late Miocene transition: link age to the establishm ent of the modern global ocean conveyor. In Proc. ODP, Sci. Results Vol. 165 (ed. R.M. Leckie, Siquardssom, H., Acton, G. D., and Draper, G.), pp. 249-273. Savin S.M., Keller G., Douglas R.G., K illingley J.S., Shaughnessy L., Sommer M.A., Vincent E., and Woodruff F. (1981) Miocene benthic foraminiferal isotope records: A synthesis. Marine Micropaleontology 6 423-450. Scher H.D., and Martin E.E. (2004) Circu lation in the Sout hern Ocean during the Paleogene inferred from Nd isotopes. Earth Planet. Sci. Lett. 28 391-405. Scher H.D., and Martin E.E. (2006) Timing and climatic consequences of the opening of Drake Passage. Science 312 428-430. Schneider B., and Schmittner A. (2006) Simulating the im pact of the Panamanian seaway closure on ocean circulation, marine productivity and nutrient cycling. Earth Planet. Sci. Lett. 246 367-380. Schnitker D. (1980) North Atlantic oceanography as possible cause of Antarctic glaciation and eutrophication. Nature 284 615-616. Segl M., Mangini A., Bonani G., Hofmann H.J., Nessi M., Sutte r M., Wolfli W., Friedrich G., Pluger W.L., Wiechowski A., and Beer J. (1984) 10Be dating of manganese crust from Central North Pacific and imp lications for oceanic paleocirculation. Nature 309 540-543.

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73 Shackleton N.J., Crowhurst S., Hagelberg T., Pisias N.G., and Schneider D.A. (1995a) A new Late Neogene time scale: application to Leg 138 sites. In Proc. ODP, Sci. Res. Vol. 138 (ed. N.G. Pisias, N.A. Mayer, T.R. Janecek, A. Palmer-Julson, and T.H. van Andel), pp. 73-101. Shackleton N. J., Baldauf J.G., Flores J.-A., Iwai M., Moore Jr. T.C. Raffi I., and Vincent E. (1995b) Biostratigraphic Summary for Leg 138. In: Pisias, N. G., Mayer L.A., Janecek T.R., Palmer-Julson A., and van Andel T.H. (Ed.), Proc. ODP, Sci. Res. Ocean Drilling Program, College Station, TX. Shackleton N.J., and Hall M.A. (1995) Stable isotope record s in bulk sediments (Leg 138). In: N.G. Pisias, N. A. M., T.R. J anecek, A. Palmer-Julson, and T.H. van Andel (Ed.), In Proceedings of the Ocean Drilli ng Program, Scientific Results Ocean Drilling Program, College Station, TX. Shackleton N.J., and Hall M.A. (1997) The late Miocene stable isotope record, Site 926. In: Shackleton, N. J., Curry, W.B., Richter, C., and Bral ower, T.J. (Ed.), Proc. Ocean Drilling Prog., Scientific Results 154 Shackleton N.J., and Crowhurst S. (1997) Sediment fluxes based on an orbitally tuned time scale 5 Ma to 14 Ma, Site 926. In Proc. ODP, Sci. Results Vol. 154 (ed. N. J. Shackleton, Curray, W.B., Richter, C., and Bralower, T.J.), pp. 69-82. Shaw H.F., and Wasserburg G.J. (1985) Sm -Nd in marine carbonates and phosphates: Implications for Nd in seawater and crustal ages. Geochim. Cosmochim. Acta 54 2433-2438. Sigurdsson H., Leckie R.M., Acton G.D., et al. (1997) Proceeding of the Ocean Drilling Program, Initial Reports Ocean Drilling Program, College Station, TX. Spivack A.J., and Wasserburg G.J. (1988) Neodymium isot opic composition of the Mediterranean outflow and the eastern North Atlantic. Geochimica Cosmochimica Acta 52 2762-2773. Staudigel H., Doyle P., and Zindler A. (1985 ) Sr and Nd isotope systematics in fish teeth. Earth Planet. Sci. Lett. 76 45-56. Steph S., Tiedemann R., Prange M., Groeneveld J., Nrnberg D., Reuning L., Schulz M., and Haug G.H. (2006) Changes in Ca ribbean surface hydrography during the Pliocene shoaling of the Central American Seaway. Paleoceanography 21 PA4221. Tachikawa K., Jeandel C., and Roy-Barman M. (1999a) A new approach to the Nd residence time in the ocean: the role of atmospheric inputs. Earth Planet. Sci. Lett. 170 433-446.

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74 Tachikawa K., Jeandel C., Vangriesheim A., and Dupre B. (1999b) Dis tribution of rare earth elements and neodymium isotopes in suspended particles of the tropical Atlantic Ocean (EUMELI site). Deep-Sea REs. I: Oceanogr. Res. Pap. 46 733755. Tachikawa K., Athias V., and Jeandel C. (2003) Neodymium budget in the modern ocean and paleo-oceanographic implications. Journal of Geophysical Research 108 3254. Talley L.D. (1993) Distribution and formation of North Pacific intermediate water. Journal of Physical Oceanography 23 517-537. Thomas D.J., Bralower T.J., and Jones C.E. (2003) Nd isotopic reconstruction of Late Paleocene-Early Eocene the rmohaline circulation. Earth Planet. Sci. Lett. 290 309-322. Thomas D.J. (2004) Evidene for deep-water production in the North Pacific Ocean during the early Cenozoic warm interval. Nature 430 65-68. Thomas D.J., and Via R.K. (2007) Neogene evolution of Atlantic thermohaline circulation: Perspective from Walvis Ridge, southeastern Atlantic Ocean. Paleoceanography 22 PA2212. van de Flierdt T., Frank M., Halliday A.N ., Hein J.R., Hattendorf B., Gunther D., and Kubik P.W. (2004) Deep and bottom wate r export from the Southern Ocean to the Pacific over the past 38 million years. Paleoceanography Via R.K.., and Thomas D.J. ( 2006) Evolution of Atlantic t hermohaline circulation: Early Oligocene onset of deep-water pr oduction in the North Atlantic. Geology 34 441444. von Blanckenburg F., and Igel H. (1999) Later al mixing and advection of reactive isotope tracers in ocean basins: observations and mechanisms. Earth Planet. Sci. Lett. 169, 13-128. Wei W. (1995) The initiation of North Atlantic Deep Wa ter as dated by nannofossils. J. Nannopl. Res. 17 90-91. Wei W., and Peleo-Alampay A. (1997) Onset of North Atlantic Deep Water as dated by nannofossils. Proceedings-30th International Geological Congress, Marine Geology and Paleoceanography 13 57-64. Woodruff F., and Savin S.M. (1989) Miocene deepwater oceanography. Paleoceanography 4 87-140.

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75 Wright J., Seymour R.S., and Shaw H.F. (1984) REE and Nd isotopes in conodont apatite: Variations with geologic al age and depositional environment. GSA Spec. Paper 196 325-340. Wright J.D., Miller K.G., and Fairbanks R .G. (1991) Evolution of modern deepwater circulation: Evidence from the Late Miocene Southern Ocean. Paleoceanography 6 275-290. Wright J.D., and Miller K.G. (1992) Ea rly and middle Miocene stable isotopes: implications for deepwater circulation and climate. Paleoceanography 7 357389. Wright J.D., and Miller K.G. (1996) Contro l on the North Atlant ic Deep Water. Paleoceanography 11 157-170.

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76 BIOGRAPHICAL SKETCH Derrick Richard Newkirk was born in Indianapol is, Indiana. He is the eldest son of Patricia and Richard Newkirk, a nd the older brother of Ryan Newkirk. His primary education, elementary through high-school, was complete d in Greenwood, Indiana. While attending Indiana University ~ Purdue University at Indianapolis he became interested in geology after taking an introductory course taught by Bob Barr. After comp letion of his four years of eligibility for collegiate soccer, he turned his focus to geology. During his undergraduate education he worked as a lab assistant for Dr. Gabriel Filippelli, and helped Dr. Filippelis Ph.D. student at the time, Dr. Jennife r Latimer. While working under Dr. Gabriel Filippelli and Dr. Jennifer Latimer he worked on his own resear ch project looking at human impacts on the watershed of Laguna Zoncho, Costa Rica using p hosphorus geochemistry. This invaluable experience doing scientific research led him to gr aduate school. He completed his degree in the summer of 2004 with a Bachelor of Science with a focus in geology. At the University of Florida his research focused on the Miocene carbona te crash using Nd in fossil fish teeth to reconstruct ocean circulation. After completion of the Master of Science degree, he plans on continuing at the University of Florida and pur suing his Ph.D. under the guidance of Dr. Ellen Martin.