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Geochemical, Mineralogical, and Rock Magnetic Provenance Variation in Alaskan Abyssal Plain Sediments, Gulf of Alaska

Permanent Link: http://ufdc.ufl.edu/UFE0041931/00001

Material Information

Title: Geochemical, Mineralogical, and Rock Magnetic Provenance Variation in Alaskan Abyssal Plain Sediments, Gulf of Alaska
Physical Description: 1 online resource (98 p.)
Language: english
Creator: Ullrich, Alexander
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2010

Subjects

Subjects / Keywords: alaska, climate, environmental, geochemistry, glacier, mineralogy, sedimentology, tectonics
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: Glaciated orogenic belts such as those of southeastern Alaska provide ideal environments in which to investigate climate-tectonic interactions, because of significant glaciogenic sediment production and transport along an active plate boundary. The sedimentary record of this interaction has a high potential for preservation in adjacent basins like the Gulf of Alaska because of a very reduced transport distance from sediment source to deepwater sink. The Surveyor Fan in the northern Gulf of Alaska contains seismic stratigraphic evidence of a substantial shift in sedimentation type and source. Based on limited age control from DSDP Site 178 this shift occurs at 1 Ma, which approximately correlates to increased glacial sediment input and accelerated exhumation of onshore terranes. This coincides with significantly increased global glaciation following the Mid-Pleistocene Transition (MPT). I hypothesize that the compositional changes in Surveyor Fan fine-grain sediments observed at Site 178 are related to intensified glaciation at 1 Ma, which resulted in focused erosion along the windward side of the St. Elias Range, as well as formation of cross shelf sea valleys that isolated sediment transport pathways to the Surveyor Channel. Here, I address this hypothesis by developing preliminary source terrane signatures of fine-grained sediment and applying them to offshore sediments of the Surveyor Fan. This is done by employing multiple analytical tools shown to be effective in previous provenance studies, including trace and major elemental geochemistry, quantitative mineralogy, and environmental magnetic properties. Results of these analyses suggest that fine-grained sediments from the Orca and Valdez Groups of the Chugach-Prince William Terranes and the Kulthieth Formation of the Yakutat Terrane represent mafic and felsic compositional end members, respectively. Surveyor Fan samples are of an intermediate composition between these end members, with no apparent compositional distinction between upper and lower fan constituents. Variability in elemental composition, however, is significantly decreased in upper fan sediments supporting the hypothesis that transport pathways were isolated following the MPT at ca. 1 Ma.
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 Alexander Ullrich.
Thesis: Thesis (M.S.)--University of Florida, 2010.
Local: Adviser: Jaeger, John M.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2012-08-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2010
System ID: UFE0041931:00001

Permanent Link: http://ufdc.ufl.edu/UFE0041931/00001

Material Information

Title: Geochemical, Mineralogical, and Rock Magnetic Provenance Variation in Alaskan Abyssal Plain Sediments, Gulf of Alaska
Physical Description: 1 online resource (98 p.)
Language: english
Creator: Ullrich, Alexander
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2010

Subjects

Subjects / Keywords: alaska, climate, environmental, geochemistry, glacier, mineralogy, sedimentology, tectonics
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: Glaciated orogenic belts such as those of southeastern Alaska provide ideal environments in which to investigate climate-tectonic interactions, because of significant glaciogenic sediment production and transport along an active plate boundary. The sedimentary record of this interaction has a high potential for preservation in adjacent basins like the Gulf of Alaska because of a very reduced transport distance from sediment source to deepwater sink. The Surveyor Fan in the northern Gulf of Alaska contains seismic stratigraphic evidence of a substantial shift in sedimentation type and source. Based on limited age control from DSDP Site 178 this shift occurs at 1 Ma, which approximately correlates to increased glacial sediment input and accelerated exhumation of onshore terranes. This coincides with significantly increased global glaciation following the Mid-Pleistocene Transition (MPT). I hypothesize that the compositional changes in Surveyor Fan fine-grain sediments observed at Site 178 are related to intensified glaciation at 1 Ma, which resulted in focused erosion along the windward side of the St. Elias Range, as well as formation of cross shelf sea valleys that isolated sediment transport pathways to the Surveyor Channel. Here, I address this hypothesis by developing preliminary source terrane signatures of fine-grained sediment and applying them to offshore sediments of the Surveyor Fan. This is done by employing multiple analytical tools shown to be effective in previous provenance studies, including trace and major elemental geochemistry, quantitative mineralogy, and environmental magnetic properties. Results of these analyses suggest that fine-grained sediments from the Orca and Valdez Groups of the Chugach-Prince William Terranes and the Kulthieth Formation of the Yakutat Terrane represent mafic and felsic compositional end members, respectively. Surveyor Fan samples are of an intermediate composition between these end members, with no apparent compositional distinction between upper and lower fan constituents. Variability in elemental composition, however, is significantly decreased in upper fan sediments supporting the hypothesis that transport pathways were isolated following the MPT at ca. 1 Ma.
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 Alexander Ullrich.
Thesis: Thesis (M.S.)--University of Florida, 2010.
Local: Adviser: Jaeger, John M.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2012-08-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2010
System ID: UFE0041931:00001


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1 GEOCHEMICAL, MINERAL OGICAL, AND ROCK MAG NETIC PROVENANCE VARIATION IN ALASKAN ABYSSAL PLAIN SEDIME NTS, GULF OF ALASKA By ALEXANDER DAVID ULLRICH 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 2010

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2 2010 Alexander David Ullrich

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3 To my family

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4 ACKNOWLEDGMENTS I wish to acknowledge agencies that provided funding and support, including the National Science Foundation Geological Society of America Student Research Grant, and Society for Sedimentary Geology (SEPM) R. J. Weimer Grant. I also wish to thank my adviso r, Dr. John Jaeger for his patience and insight throughout this project, as well as my other committee members, Drs. Paul Mueller and Ellen Martin. I would also like to extend my appreciation to Drs. George Kamenov, Jim Channell, Joe Meert, and Kainian Hu ang, for the use of their facilities in geochemical and environmental magnetic analyses. In addition, I would like to thank my colleagues in the Department of Geological Sciences, specifically, Brittany Newstead, Derrick Newkirk, Elliott Arnold, Kate Rowe Paul Bremner, Misty Stroud, and Dylan Miner for providing much needed support and friendship. Finally, I thank my family and God for their love and support.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF TABLES ................................ ................................ ................................ ............ 7 LIST OF FIGURES ................................ ................................ ................................ .......... 8 ABSTRACT ................................ ................................ ................................ ..................... 9 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .... 11 2 BACKGROUND ................................ ................................ ................................ ...... 22 Characterization of Geologic Terranes of Southern Alaska ................................ .... 22 Chugach Prince William Terrane Lithologies ................................ .................... 23 Yakutat Terrane Lithologies ................................ ................................ .............. 24 Surveyor Fan and DSDP Site 178 ................................ ................................ .... 26 Application of Provenance Tools ................................ ................................ ............ 27 Mineralogy and Geochemistry ................................ ................................ .......... 27 Weathering and Physical Sorting in Provenance ................................ .............. 28 Environmental Magnetic Properties ................................ ................................ .. 32 3 METHODS ................................ ................................ ................................ .............. 36 Field Sampling Methods ................................ ................................ ......................... 36 Initial Sample Preparation ................................ ................................ ....................... 37 Analytical Techniques ................................ ................................ ............................. 38 4 RESULTS ................................ ................................ ................................ ............... 41 Mineralogical and Geochemical Analyses ................................ .............................. 41 Environmental Magnetic Properties ................................ ................................ ........ 45 5 DISCUSSION ................................ ................................ ................................ ......... 53 Mineralogical and Elemental Analyses ................................ ................................ ... 53 Environmental Magnetic Properties ................................ ................................ ........ 55 Chemical Weathering ................................ ................................ .............................. 56 Interpretation of Sedimentary Provenance ................................ .............................. 56 Geochemical, Mineralogical and Magnetic Characterization of Onshore Terranes ................................ ................................ ................................ ........ 57 Site 178 Sediment Provenance ................................ ................................ ........ 60

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6 Evid ence for a MPT Change In Onshore Sediment Production .............................. 61 6 CONCLUSIONS ................................ ................................ ................................ ..... 63 APPENDIX A S AMPLE LOCATIONS ................................ ................................ ............................ 68 B FINE FRACTION GRAIN SIZE ANALYSIS ................................ ............................ 71 C ENVIRONMENTAL MAGNETIC PROPERTIES ................................ ..................... 72 D MINERALOGY ................................ ................................ ................................ ........ 75 E MAJOR OXIDES (WT. %) ................................ ................................ ....................... 79 F TRACE EL EMENTS (PPM) ................................ ................................ .................... 81 G REE ABUNDANCE (PPM) ................................ ................................ ...................... 85 LIST OF REFERENCES ................................ ................................ ............................... 89 BIOGRAPHICAL SKETCH ................................ ................................ ............................ 98

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7 LIST OF TABLES Table page 2 1 Correlation coefficients for analyzed variables and grain size. ........................... 35 4 1 Mean and standard deviation values of Sit e 178 compositional variables ......... 51 A 1 Chugach River Sample Locations ................................ ................................ ...... 68 A 2 Yakutat Terrane Sample Locations ................................ ................................ .... 69 A 3 Surveyor Fan Core Sample Intervals ................................ ................................ .. 69 B 1 Percent Clay, Chugach Terrane and Surveyor Fan. ................................ ........... 71 C 1 Environmental Magnetic Properties ................................ ................................ .... 72 D 1 Mineralogy, Chugach and Yakutat Terranes. ................................ ..................... 76 D 2 Mineralogy, Surveyor Fan. ................................ ................................ .................. 77 D 3 Mineralogy, EW0408 85JC. ................................ ................................ ................ 78 E 1 Major oxide concentration, Chugach and Yakutat Terranes. .............................. 79 E 2 Major oxide concentration, Surveyor Fan. ................................ .......................... 80 F 1 Trace element concentration, Chugach Terrane. ................................ ............... 82 F 2 Trace element concentration, Yakutat Terrane ................................ ................... 83 F 3 Trace element concentration, Surveyor Fan. ................................ ...................... 84 G 1 Rare Earth Element concentration, Chugach Terrane. ................................ ....... 86 G 2 Rare Earth Element concentration, Yakutat Terrane. ................................ ......... 87 G 3 Rare Earth Element concentration, Surveyor Fan. ................................ ............. 88

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8 LIST OF FIGURES Figure page 1 1 Field setting. ................................ ................................ ................................ ....... 17 1 2 Precipitation of southeastern AK. ................................ ................................ ....... 18 1 3 Stratigraphic, depositional, and climatic events and data from the Gulf of Alaska.. ................................ ................................ ................................ ............... 19 1 4 Exhumation rates of the Chugach St. Elias ranges ................................ ........... 20 1 5 Seismic reflection profile from USGS survey line F689, northern Gulf of Alaska ................................ ................................ ................................ ............... 21 2 1 Geologic terranes of southeastern Alaska, including the Chugach Prince William and Yakutat Terranes. ................................ ................................ ............ 35 4 1 Sediment mineralogy.. ................................ ................................ ........................ 47 4 2 Percent FeO versus FeO/Al2O3 ratios. ................................ .............................. 48 4 3 Cr/Al versus Ce/P and Mg/Al ratios. ................................ ................................ ... 49 4 4 Downcore plots of grain size, elemental, and magnetic data. ............................. 50 4 5 A Day plot of hysteresis properties of southeastern Alaska sediments. ........... 52

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9 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 GEOCHEMICAL, MINERAL OGICAL, AND ROCK MAG NETIC PROVENANCE VARIATION IN ALASKAN ABYSSAL PLAIN SEDIME NTS, GULF OF ALASKA By Alexander David Ullrich August 2010 Chair: Michael R. Perfit Major: Geology Glaciated orogenic belts such as those of southeastern Alaska provide ideal environments in which to investigate climate tectonic interactions because of significant glaci o genic sediment production and transport along an active plate bounda ry. The sedimentary record of this interaction has a high potential for preservation in adjacent basins like the Gulf of Alaska because of a very reduced transport distance from sediment source to deepwater sink. The Surveyor Fan in the northern Gulf of Alaska contains seismic stratigraphic evidence of a substantial shift in sedimentation type and source. B ased on limited age control from DSDP Site 178 this shift occurs at 1 Ma, which approximately correlates to increased glacial sediment input and accel erated exhumation of onshore terranes. This coincides with significantly increased global glaciation following the Mid Pleistocene Transition (MPT) I hypothesize that the compositional changes in Surveyor Fan fine grain sediments observed at Site 178 ar e related to intensified glaciation at 1 Ma, which resulted in focused erosion along the windward side of the St. Elias Range, as well as formation of cross shelf sea valleys that isolated sediment transport pathways to the Surveyo r Channel. Here, I addre ss this hypothes i s by developing preliminary source terrane signatures of fine grain ed

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10 sediment and applying them to offshore sediments of the Surveyor Fan. This is done by employing multiple analytical tools shown to be effective in previous provenance s tudies, including trace and major elemental geochemistry, quantitative mineralogy, and environmental magnetic properties. Results of these analyses suggest that fine grain ed sediments from the Orca and Valdez Groups of the Chugach Prince William Terranes and the Kulthieth Formation of the Yakutat Terrane represent mafic and felsic compositional end members, respectively. Surveyor Fan samples are of an intermediate composition between these end members, with no apparent compositional distinction between up per and lower fan constituents. Variability in elemental composition, however, is significantly decreased in upper fan sediments supporting the hypothesis that transport pathways were isolated following the MPT at ca. 1 Ma.

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11 CHAPTER 1 INTRODUCTION The interplay between regional tectonic activity and climate is a fundamental issue in the earth sciences. In particular, the denudation of uplifting coastal mountain ranges, creation of sediment, and transport of this mass into adjacent basins plays an i ntegral role in changing regional tectonic stresses (Roe et al., 2006; Tompkin and Roe, 2007). These interactions are especially significant in regions of high topographic relief coupled with aggressive erosional agents, such as glaciated orogenic belts. Glaciation of uplifting mountain belts results in greatly accelerated denudation and transport of mass toward adjacent basins (Spotila et al., 2004). This generates a positive feedback loop of isostatic rebound and accelerated uplift, which in turn promo tes further glacial erosion (Spotila et al., 2004; Tompkin, 2007). The onset of coastal orogenesis as well as weathering and transport processes are recorded in the sediment deposition on adjacent basins and fans (Klein, 1984). Changes in sediment produ ction and transport in uplifting orogens and the preservation of these changes in adjacent depositional basins have been the focus of recent studies (i.e., Jaeger et al., 1998, 2006; Cloetingh et al., 2005). Offshore basins adjacent to glaciated regions o ffer several advantages in these investigations, including a relatively direct depositional input, as well as minimized alteration of sediment composition due to weathering and physical sorting processes (Jaeger et al., 2001; Young and Nesbitt, 1998). The Surveyor Fan in the northern Gulf of Alaska (GoA), for example, receives its sediment predominantly from adjacent coastal mountains of southern Alaska (Figure 1 1). Glaciated mountain belts on the northern margins of this basin provide a much greater inp ut of sediment in comparison to non glaciated

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12 mountain belts of similar size and topographic relief, resulting in some of the highest offshore sedimentation rates in the world (Hallet et al., 1995; Jaeger et al., 1998). In addition to extremely rapid accu mulation rates, sediment is transported directly from the coastal ranges of southern Alaska to the Surveyor Fan, with minimal residence time in terrestrial basins or floodplains (Jaeger et al., 2001). This close proximity of source to sink, in addition to rapid transport and deposition of sediment offshore into a geographically limited region, results in hypothetically strong preservation potential of sediment composition that aids in the development of high resolution histories of onshore geomorphic and t ectonic processes. The presence of the highest coastal mountain range on the planet next to an abundant moisture source has resulted in a tight coupling of climate and tectonics in the Gulf of Alaska. Winds transport moisture from the North Pacific lan dward, resulting in >3 m yr 1 in precipitation along coastal mountain ranges (Figure 1 2). High precipitation in conjunction with a cooling climate at 5 Ma resulted in alpine glaciation developing along the south facing windward side of the Chugach St. Elias Fairweather Ranges, which further expanded into Cordilleran Glaciation at 2.6 Ma (Lagoe et al., 1993) (Figure 1 3). This resulted in the formation of tidewater glaciers and accelerated terrigenous input into the GoA, as well as the appearance of ice rafted debris (IRD; Lagoe et al ., 1993). Globally, during the Mid Pleistocene Transition (MPT) at about 1 Ma, several studies suggest that the dominant periodicity of glacial cycles shifted from 41,000 years to 100,000 years, due to increased obliquity forcing within Milankovitch cycle s (Clark et a., 2006; Berger et al., 2008). Associated intensification of glaciations following the MPT may have resulted in greatly accelerated mass transport in southern Alaska, as a

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13 subsequent two fold increase in terrigenous input to the GoA is observ ed at this time (Rea and Snoeckx, 1994). Also, low temperature thermochronology by Berger et al. (2008) indicates that accelerated removal of material from onshore terranes within the last ~1 Ma may have resulted in greatly increased regional exhumation r ates (Figure 1 4). Prevailing precipitation on the windward side of the St. Elias range suggests that intensified glaciation would have been concentrated in this region, and resulted in greater removal of material along this front. In addition, the trans ition to 100 ky glacial cycles may have led to ice stream formation along the Alaskan coastline, which subsequently incised cross shelf sea valleys through glacial scouring and Jokulhaup events (Reece, 2009; Mayer, 2005; Milliman et al.,1996). These perma nently incised channels would have then acted as direct sediment conduits to the continental slope and Surveyor Channel and Fan. A basic framework Neogene chronology for the Surveyor Fan, the offshore sediment depocenter of onshore sediment erosion, allow s for the development of a time line of glacial denudation through various source terranes (Lagoe et al., 1993; Plafker, 1987; Plafker and Berg, 1994; Plafker et al., 1994). For these reasons, the Surveyor Fan in the northern GoA may offer detailed insigh t into the erosional response of GoA bordering orogenic belts to shifts in Neogene climate. In particular, sediment cores collected from Deep Sea Drilling Project (DSDP) Site 178, contain Quaternary to Miocene age sediment, and are derived predominantly f rom sources in coastal mountain belts surrounding the basin to the north and east. Erosion of these mountain ranges and delivery of sediment to the Surveyor Fan has subsequently produced distinct seismic reflectors in offshore sediments that have been used to designate

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14 upper middle and lower fan sequences within the Surveyor Fan (Figure 1 5; Reece, 2009; Stevenson and Embley, 1987). Biostratigraphic age depth correlations of GoA seismic profiles suggest that deposition of the upper fan sequence may be coincident with the onset of the Mid Pleistocene intensification of glaciation at ~1 Ma, (Reece, 2009). A change in the rate of terrigenous input to Site 178 at ~ 1 Ma also may coincide with changes in lithologic properties (i.e., mineralogy and geochemis try) and offer evidence for a shift in sedimentation regime that coincides with the intenstification of Northern Hemisphere glaciation during the MPT (Kulm et al., 1973; Rea and Snoeckx, 1995). ska Continental Margin: 1 hypothesis that the MPT resulted in rapid acceleration in exhumation due to the creation of highly erosive ice streams as reflected in the onset in the f ormation of northern GoA sea valleys (e.g. Kayak, Pamplona, Yakutat, Alsek). This thesis is a pilot project to determine if there are stratigraphic and sedimentary provenance records of the impact of the MPT preserved in the Surveyor Fan. Prior to ice str eam formation following the MPT, sediment transport pathways from the coastal mountains to the adjacent Surveyor Fan hypothetically were not restricted to the large sea valleys, and therefore, sediment likely was supplied from a broader range of onshore so urces to the Surveyor Fan. Following the MPT, development of glacially carved troughs on the continental shelf would have resulted in a sediment transport path to the Surveyor Channel that was t Block (Stevenson and Embly, 1987). I hypothesize that isolation of the Surveyor Channel at 1 Ma is

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15 accompanied by focused erosion along the windward side of the St. Elias range, and the resultant variations in sediment production and transport pathways to the Gulf of Alaska would be recorded in the composition of Surveyor Fan sediments. This would thereby elucidate the relationship between the evolution of Surveyor Fan deposition, and variation in onshore sediment production and transport. Here, I test this hypothesis by examining the provenance of fine material from DSDP Site 178 on the Surveyor Fan. Sedimentary provenance analysis is typically accomplished with detrital zircon age patterns from the sand fraction of sediments in basin a nalysis studies (Fedo, 2003). The majority of sediment accumulating in the Surveyor Fan, however, is silt to clay sized (Kulm et al., 1973) and analysis of the sand fraction provenance potentially could provide information on sediment erosion and dispers al that is biased with respect to original source rock composition. For fine grain sediments, other provenance techniques are used, including bulk mineralogy and trace and major elemental analyses (McLennan et al., 2003; Nesbitt and Young, 1996). The cha racterization of the onshore sediment sources using these tools along the GoA margin has not been done because of the inaccessibility of the coastal mountains. Consequently, the first goal of this project is to determine the provenance tools most applicab le in characterizing the composition of potential onshore sediment sources, focusing on the simplest and most efficient methods. Secondly, compositional signatures of source terranes are compared with sediments collected at DSDP Site 178 from upper middl e and lower fan sequences to determine which of these provenance characteristics is preserved in the offshore basin.

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16 Finally, those variables that best record source composition in offshore sediments are used in distinguishing any variation in sediment p rovenance among fan sequences.

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17 Figure 1 1. Field setting. The southeastern coast of Alaska has high coastal mountain ranges along the edge of an active tectonic boundary and which have been extensively glaciated throughout the Holocene.

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18 Figure 1 2. Precipitation of southeastern AK. Rates of precipitation in southeastern Alaska are highest along the windward side of the Chugach St. Elias ranges, exceeding 3 m yr 1. This is contrary to the leeward side along which precipitation rates are approx imately 0.5 1.5 m yr 1 (2000 2002 OSU Spatial Climate Analysis Service).

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19 Figure 1 3. Stratigraphic, depositional, and climatic events and data from the Gulf of Alaska. An increase in sediment accumulation in the distal GoA (ODP Site 887) correlates to a increase in global glacial coverage as represented by oxygen isotope data from Lisiecki and Raymo (2005) (black) and Zachos et al. (2001) (gray). Significant increase in mass accumulation in the GoA occurs at approximately 1 Ma, coinciding with the Mid Pleistocene transition, and the occurrence of abundance diamictite at Site 178. Lithological data are from Lagoe et al. (1993), Rea and Snoeckx (1995), and Lagoe and Zellers (1996). Tectonic events from Lagoe et al. (1993), Stevenson and Embley (1987), Spotila et al. (2004).

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20 Figure 1 4. Exhumation rates of the Chugach St. Elias ranges after Berger et al. (2008). A) Low temperature apatite thermochronology of Berger et al. (2008) as well as U/Pb dating of detrital zircons by Enkelmann et al. (2009) indicate exhumation rates of ~1 km/Myr 1 B) At approximately 1 Ma, exhumation rates increased significantly to ~4 km/Myr 1 In addition, the peak of this exhumation shifted at this time to the windward side of the St. Elias range.

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21 Figure 1 5. Seismic reflection profile from USGS survey line F689, northern Gulf of Alaska (see Figure 1 1 for location). Pronounced seismic reflectors at approximately 140 m (~0.25 sec) and 330 m (~0.5 sec) separate the Surveyor Fan into three fan sequences. The lo wer boundary of the upper fan sequence (UFS) at 137 m coincides with 1 Ma, when correlated to biostratigraphic ages (Kulm e t al., 1973; Zellers, 1995). The boundary at 3 30 m divides the lower portion of the Surveyor Fan into middle and lower fan sequence s (MFS, LFS). Profile and interpretation after Reese (2009).

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22 CHAPTER 2 BACKGROUND Characterization of Geologic Terranes of Southern Alaska Southern Alaska consists of an amalgamation of several accreted terranes, resulting from the northwestward subduction of the Pacific Plate at a rate of 5.6 cm yr 1 (Figure 2 1; Plafker, 1987; Plafker et al., 1994; Bruhn et al., 2004). Active subduction resulted in accretionary uplift of the Chugach, St. Elias, and Fairweather Ranges along the coast of the GoA over the past 60 Ma, with significant uplift in the Chugach St. Elias ranges in the past 20 Ma (Plafker et al., 1994). Approximately 50% of the coastal Alaskan mountain ranges is currently glaciated, resulting in extremely high mass transport of sediment to the Surveyor Fan in the adjacent basin (Meigs and Sauber, 2000). Major accreted terranes in southern coastal Alaska include the Yakutat, Prince William, and Chugach, (Plafker, 1987; Plafker et al., 1994). The Yakutat Terrane consists of Late Mesozoic Paleogene sedimentary rocks (Yakutat, Poul Creek, and Kulthieth Formations; Plafker, 1987), which were suggested to have been derived from Coast Mountains of British Columbia (Bruns, 1983; Cowan, 1982; Stevenson and Embley, 1987, Perry et al., 2009). The Prince William, Chugach, and Wrangellia Terranes consist predominantly of meta sedimentary flysch deposits that have undergone subduction and subsequent metamorphism (Plafker, 1987 ; Gehrel s and Saleeby, 1987 ; Haeussler et al., 2004). Accreted terranes o f southern Alaska are composed predominantly of sedimentary deposits that have undergone varying degrees of metamorphism up to amphibolite

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23 grade (Plafker, 1987; Plafker et al., 1994; Haeussler et al., 1997). This study focuses on two of these terranes, t he Chugach Prince William Terranes and Yakutat Terrane. Chugach Prince William Terrane Lithologies The Chugach and Prince William Terranes are lithologically similar, and have been considered one composite terrane for the purposes of this study (hereafte r referred to as the Chugach Terrane; Kusky et al., 1997). Age distributions of detrital zircons suggest metasedimentary flyschoidal rocks of the Chugach Terrane are derived from inboard accreted terranes of British Columbia (Haeussler et al, 2004). The lithologies of Chugach Terrane are dominated by greywacke flysch, as well as mlange units that exhibit significant basaltic constituents. These mafic units have undergone very low grade metamorphism in the westernmost terrane, increasing in metamorphic gr ade to amphibolite facies and phyllitic units of the Orca and Valdez Groups in the St. Elias region (Figure 2 1; Plafker et al., 1994; Haeussler et al., 2004). Greywacke flysch units are recognized from Kodiak Island to the Kenai Mountains along the Kenai Peninsula, and extend to the northern Chugach Mountains (Plafker et al., 1994). Greenschist facies mineral assemblages are prevalent within the western Chugach Terrane, including epidote, actinolite, chlorite, quartz, calcite, and white mica (Barker, 1994 ). The Valdez Group of the Chugach Terrane north of the St. Elias Range is part of a mlange that is characterized by metavolcanic rocks and weakly foliated, green, glassy tuff, together with greenish grey volcaniclastic greywacke, and dark gray to black a rgillite (Plafker et al., 1994). The composition changes from west to east, indicating derivation from progressively deeper levels of a magmatic arc (Plafker et al., 1994).

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24 Volcanic rocks of the southern margin of the Valdez Group are dominantly tholeiit ic pillow basalts with island arc to MORB compositions (Plafker et al., 1994). The Orca Group, a portion of which is shown in Figure 2 1, dominates the Prince William Terrane within the St. Elias Range, and for the purposes of this study is included with the Chugach Terrane. As with the Valdez Group, this group is a deep sea flysch complex with abundant oceanic basaltic rocks that forms a belt more than 100 km wide, extending from the St. Elias mountains southwest beneath the continental shelf and slope (Plafker et al., 1994). Volcanic constituents of the Orca Group are typically altered basalt associated with sheeted dikes and gabbroic intrusions of an ophiolite complex (Plafker et al., 1994). The Orca and Valdez Groups contain significant basaltic con stitutes and underlie the Bagley Ice Field along the Contact Fault System, from which the Bering Glacier sources (Plafker et al., 1994; Richter et al., 2006). I suggest that both the Orca and Valdez Groups are represented by sediments of core EW0408 85JC (Figure 2 1), which will be discussed below. Yakutat Terrane Lithologies The Yakutat Terrane is divided geographically into two major segments consisting of the Dangerous River Zone (DRZ, Figure 2 1) in the far east of the terrane, and the Pamplona Zone, j uxtaposed just to the west of the DRZ. Units within the Pamplona Zone are lithologically similar and composed of Cenozoic offshore continental shelf deposits of the Kultheth, Poul Creek, and Yakataga Formations (Risley et al., 1992; Plafker et al., 1994). These units, especially the Kultheth and Poul Creek, are likely derived from Upper Cretaceous volcanics in British Columbia followed by approximately 600 km of northwestward translation along the Queen Charlotte Fairweather fault (Plafker, 1987; Cowan, 1 982; Plafker et al., 1994).

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25 Kulthieth Formation sediments were deposited approximately 60 35 Ma and consist of non marine to shallow marine, deltaic, feldspathic and micaceous sandstones and siltstones (Risley et al., 1992; Plafker et al., 1994). At the t ime of Kulthieth Formation deposition, sediment transport pathways to offshore depositional basins in the Gulf of Alaska likely originated from the east, deriving material from the Coast Mountains in British Columbia during the latter stages of uplift (Pla fker et al., 1994). The Coast Mountains are predominantly plutonic bodies of granite and granodiorite. The highly felsic composition of uplifting onshore source terranes at this time suggests that the Kulthieth Fomation should be composed of recycled plu tonic material of Al Na and Si rich composition, which is consistent with the reported mineralogy of this unit (Plafker, 1987; Risley et al., 1992; Plafker et al., 1994). The Poul Creek Formation ranges in age from late Eocene to Oligocene and represen ts deposition during a general marine transgression in outer shelf/slope environment (Risley et al., 1992; Plafker et al., 1994). This formation is characterized by a high abundance of argillaceous sediment that is in part glauconitic, organic rich, and c ontains volcaniclastic material (Plafker, 1987; Risley, 1992; Plafker et al., 1994). The Miocene to Pleistocene Yakataga Formation represents a glacimarine shelf/slope deposit and is distinguished by glacially deposited siliciclastic sediments ( Plafker, 19 87; Eyles et al. 19 91 ; Plafker et al., 1994). These sediments were deposited late in the accretionary history of the Yakutat Terrane, and are predominantly derived from Chugach Terrane as indicated by lithologies of diamictite dropstones and bioturbated sandstones (Lagoe et al., 1993; Perry et al., 2009). To date, trace and

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26 major element geochemistry of the fine fraction of Yakutat Terrane rocks has not been investigated. Surveyor Fan and DSDP Site 178 Northwestward translation of the Yakutat m icroplate during the late Miocene was coeval with the inception of Surveyor Fan deposition in the Gulf of Alaska (GoA) at approximately 10 Ma, and synchronous with continued deposition of the Yakataga Formation (Plafker, 1987; Stevenson and Embley, 1987; Plafker et al., 1994). Drill cores of GoA sediments collected at DSDP Site 178 are representative of two dominant sediment lithologies comprising the Surveyor Fan ( Figure 1 3; Stevenson and Embley, 1987). Sediment within the upper 0 140 m eters below sea floor (m bsf ) consists of thick bedded silty clay with diatom rich intervals, and abundant diamictite beds. Below this depth, diamictite beds decreas e in abundance and at 280m (280 742 m) sediments are dominated by fine grained mud and silt with intercalated turbidi te beds (Kulm et al., 1973). At 742 m, sedimentary units unconformably overlie chalk, which itself overlies basaltic basement (Kulm et al., 1973). The entire Surveyor Fan can be divided into Upper and Middle and Lower Fan Sequences (UFS, MFS, and LF S, respectively), separated by pronounced reflectors in seismic profiles of the GoA taken along a NE SW transect adjacent to DSDP Site 178 (Figure 1 5; USGS survey F689). Depths calculated from original seismic velocities of Kulm et al. (1973) place the u ppermost reflector at approximately 140 mbsf, an intermediate reflector at 333 mbsf, and lower reflector, representing basement rock, at approximately 740 mbsf (Reece, 2009). These pronounced seismic reflectors are correlative with several prominent age depth relationships. Biostratigraphic data indicate that the boundary observed at ~140

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27 mbsf in seismic profiles coincides with a date of approximately 1 Ma, an age that corresponds to the beginning of the MPT (Kulm et al., 1973; Lagoe et al., 1993). Argo n Argon age dating done by Hogan et al. (1978) on several ash layers within Site 178 suggest the intermediate reflector at 333 mbsf corresponds to an age of 5.5 Ma, and is coincident with the onset of tidewater glaciation just prior to the Cordilleran glac iations; however, poor core recovery prevents robust 40 Ar/ 39 Ar age control (Lagoe et al., 1993). These relationships between seismic reflection profiles and age depth intervals suggest that the lower bounds of the upper and middle fan sequences correspon d to these significant climatic transitions (Fig ure 1 3). Application of Provenance Tools Mineralogy and Geochemistry A variety of sedimentary provenance tools have been successfully applied in differentiating fine grain sediment derived from a range of tectonic settings (e.g. McLennan et al., 2003; McLennan et al., 1993; Taylor and McLennan, 1985; Bhatia and Crook, 1986) Application of geochemical analysis in sedimentary provenance is well established (Lee et al., 2005; Schoster et al., 2000; Bhatia and Cr o ok 1986; Muhs, et al., 2008; McLennan et al., 1982, 1993, 2003; Taylor and McLennan, 1985). For example, the dist ribution of ferromagnesian (Cr, Mg, V, Ni, Co) elements has been applied to provenance studies in the past to indicate mafic sources (McClennan et al., 2003). Isotopic analysis of Nd, Sr, Ar, and Rb is also useful in delineating potential source terranes based on age, and has been applied in previous studies such as those by Hemming et al. (2007) and Farmer et al. (2003). Other provenance tools that have previously been applied include quantitative mineralogy (Eberl, 2003; An d rews and Eberl, 2007) and en vironmental magnetic properties (Cowan et al., 2006; Liu et al.,

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28 2003). Such traditional provenance tools are most useful when potential source terranes are significantly different in composition (i.e. ophiolitic versus granitic sources or significantly d ifferent tectonic settings). Abundance of trace elements such as Cr is highly influenced by heavy minerals such as monazite and zircon, as well as Cr rich variants of common aluminous minerals such as fuchsite (Dinelli et al., 2007). Normalizing Cr and o ther elements to Al help to distinguish whether the abundance of a particular element in fine grained sediment is due to the presence of aluminous clays and phyllosilicates, or other mineral phases. Ratios of Mg/Al as well as FeO/Al 2 O 3 can also be tied to the presence of Fe and Cr rich clay minerals. Cerium phosphorus ratios are largely affected by the presence of heavy minerals common in metamorphic and mafic rocks, such as monazite and apatite (Spear and Pyle, 2002). In addition, the concentration of Fe is often directly proportional to magnetic susceptibility, which is influenced by the mineralogic carriers of those elemental constituents (e.g. magnetite vs. hematite). These carriers also dictate the behavior of magnetic hysteresis properties of a sa mple (Cowan et al., 2006; Evans and Heller, 2003). Weathering and Physical Sorting in Provenance Some well established provenance tools such as quantitative mineralogy and trace and major geochemistry can be significantly affected by sedimentary processes such as weathering and physical sorting (Diekmann et al., 2000; Schoster et al., 2000; Andrews and Eberl, 2007; Eberl, 2003). The most useful sediments in provenance studies are those that have undergone little alteration since being weathered and transpo rted from the original bedrock (Young and Nesbitt, 1998; Dinelli et al., 2007). Certain mineral phases are significantly affected by these processes, such as minerals

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29 that are susceptible to weathering (i.e., olivine, pyroxene, and chlorite). Significant alteration of these mineral phases through chemical weathering processes may result in the loss of mobile or incompatible elements associated with the un altered phases (i.e., Ca, Na, K), thereby producing a compositional bias in altered sediment compositi on with respect to original source rock (Dinelli et al., 20 0 7). Likewise, physical weathering processes tend to concentrate weathering resistant minerals (i.e. quartz) in the coarse grained size fraction, while synchronously concentrating easily weathered material in the fine grained size fraction (i.e., muscovite, biotite). The effect of preferentially concentrating mineral phases within specific size fractions, and chemical removal of more mobile elemental constituents produces significantly skewed conc entrations of elements within deposited sediments, obscuring compositional signatures of original source rocks (Dinelli et al., 2007). For this reason, age grouping of resistant detrital zircons within sand fraction sediments is often used in provenance s tudies (e.g. McClennan et al., 2001 ; Haeussler et al., 2004 ; Cardona et al., 2009; ). Compositional biasing (with respect to source rock composition) due to these processes can be partly overcome, however, by taking multiple approaches in determining prov enance. For elemental and mineralogical components, weathering and sorting are difficult to distinguish because weathering processes occur synchronously with sediment transport and subsequent sorting (McLennan et al., 2003). In sediments that are dominat ed by fine grained material, for example, major elements such as Ti are constituents of mineral phases that are susceptible to physical and chemical weathering (e.g., biotite). A more mafic sediment source would likely yield greater abundance of these Ti bearing phases in the fine grained sediment fraction; however, any increase in

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30 Ti concentration may be masked as this concentration is reduced due to chemical alteration of these Ti bearing phases into Ti depleted clay residuals (i.e., removal of Ti during weathering of muscovite to kaolinite; Singh and Gikes, 1991). Cerium Phosphorus, Cr/Al, and Mg/Al ratios, however, have been observed to not correlate with grain size (Bhatia and Crook, 1986; Dinelli et al., 2007). Major elemental constituents such as T iO 2 /Al 2 O 3 ratios also reflect the degree of chemical weathering in sediments; however, in recycled sedimentary material, these ratios may reflect the degree of weathering undergone by original sedimentary components (Young and Nesbitt, 1998). A low degree of weathering exhibited by unrecycled sediments suggests that geochemical components are useful in deriving provenance, because geochemical constituents will reflect those of onshore sources. In glaciated regions, weathering of original source rock is ass umed to be comparatively minimal relative to tropical basins such as the Amazon, in which chemical alteration occurs more rapidly ( Johnsson and Mea, 1990 ; Young and Nesbitt, 1998). Glacial transport of sediments typically results in little chemical altera tion (e.g. Young and Nesbitt, 1998 ; Anderson, 2003), and transport time from coastal source terranes to the adjacent GoA is short, with onshore residence time in the tens of thousands of years (Jaeger et al., 2001). Weathering of upper continental crust i s usually dominated by the alteration of feldspars, and perhaps the most useful method of addressing the degree of weathering in sedimentary rocks is the Chemical Index of Alteration (CIA), developed by Nesbitt and Young (1984). This weathering index is g iven by: CIA = 100 [Al 2 O 3 /(Al 2 O + CaO* + Na 2 O + K 2 O)]

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31 Values of this index range from about 50 for unweathered igneous and metamorphic rocks to 100 for pure aluminosilicate residues such as kaolin. Here, CaO* refers to calcium associated with silicate minerals, and requires correction for Ca composition due to carbonates (Nesbitt and Young, 1984; McLennan et al., 2003). Another tool useful in approximating the influence of weathering is the presence of unstable mineral phases within silt and clay fract ion sediment (Bischoff and Cummins, 2001). The presence of v ery fine grained particles of unstable mineral phases (e.g., pyroxene, olivine, feldspars) suggests that these phases have not been exposed to chemical weathering processes for long enough to alt er them into more stable constituents (i.e. biotite kaolinite). Therefore, the mineralogic composition of sediments in a basin will reflect those phases present in the source (Bischoff and Cummins, 2001). The amount of chemical alteration can also be estimated by the degree of similarity among elemental abundances seen in deposited sediments and potential source terranes that are broadly similar in elemental composition. Sediments that have undergone little alteration will have abundances of mobile el ements such as Cr and Mg that are broadly similar to one or more potential source terranes. In contrast, abundances of these mobile elements would be significantly different between derived sediment and any source terranes. Substantial chemical alteratio n would result in elemental abundances that are significantly different from any potential source. Physical sorting, or the concentration of a particular grain size (and associated mineralogy) during sediment transport, is another sedimentary process that must be addressed in provenance studies (Dinelli et al., 2007). Minerals that are more resistant

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32 to physical weathering such as quartz or feldspar will not be as abundant in fine fraction sediments as easily weathered material. Minerals that are suscepti ble to physical weathering processes (e.g. chlorite, muscovite ) will be more abundant in fine grained sediments as material is transported offshore, and may cause elemental constituents found in these minerals to appear more concentrated in geochemical ana lyses of fine grained sediment (Anderson, 2005; Dinelli et al., 2007). Among trace elements, the most useful signatures can be derived from ratios that indicate a mafic or metamorphic source such as Cr and Ce, and are independent of physical grain size, su ch as those presented by Dinelli et al. (2007). Of these elements, Cr/Al and Ce/P ratios show no significant (P<0.01) correlation to clay or silt content (Table 2 1; Dinelli et al., 2007). A lack of correlation with any particular grain size fraction sug gests that these provenance tools provide a purely compositional signature, and may be useful in distinguishing sediment sources. A matrix of geochemical constituents that are least correlated to physical grain size and are relatively immobile during weat hering are given in Table 2 1, modified from Dinelli et al. (2007). Environmental Magnetic Properties In addition to geochemical constituents, magnetic properties have been successfully applied as provenance indicators (Liu et al., 2003; Cowan et al., 2006 ; Dessai et al., 2009). Day plots are a comparison of coercivity of remanence values normalized to magnetic coercivity values (H cr /H c ) versus remanent magnetization values normalized to saturation magnetization values (M r /M s ; Day et al., 1977). The position of values on a Day plot is a function of several factors, including grain size, concentration of magnetic phases, and the presence of magnetite as the dominant magnetic carrier phase (Evans and Heller, 2003). Depending u pon their grain size and what clastic

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33 material they are mixed with, magnetite grains will occupy points along a continuum extending from the finest grained single domain region (SD), through the medium grained pseudo single domain region (PSD), to the coar ser grained multi domain region (MD). Mass indicator of the concentration of magnetic minerals (e.g., magnetite, pyyrhotite, titanomagnetite) within a sample (Evans and Heller, 20 may be enhanced by concentration of ferromagnetic (e.g., magnetite, ilmenite, pyrrhotite) and Fe bearing paramagnetic mineral phases (e.g., bioitite, muscovite, values may exh ibit varying concentrations of ferromagnetic elements (i.e. Fe, Cr, Ni, Co). A study of environmental magnetic provenance variation in glacial sand sized sediment from the eastern Chugach Terrane suggest that pyrrhotite, not magnetite, is the dominant ma gnetic carrier within these samples (Cowan et al., 2006). These samples exhibit mass magnetic susceptibility values ranging from 1.59x10 7 m 3 /kg to approximately 3x10 5 m 3 /kg (Cowan et al., 2006). Very low coercivity of remanence (Hcr/Hc) and moderate to high magnetic remanence (Mr/Ms), as well as pyrrhotite Verwey transitions exhibited by low temperature remanence analyses also suggest pyrrhotite is a likely magnetic carrier in Chugach Terrane sediments, and is supported by magnetic extractions performed in the same study, which yielded little to no magnetite within each sample. In the same study, sediments derived from the Yakutat Terrane exhibit mass magnetic susceptibility measurements between 4x10 7 m 3 /kg and 2x10 7 m 3 /kg, and

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34 typically have Hcr/Hc values between 2 and 4, with Mr/Ms values between 0.05 and 0.15 (Cowan et al., 2006). Yakutat Terrane sediments exhibit a typical magnetite Verwey transition in low temperature remanence studies, and plot consistently along a magnetite mixing continuum on a Day plot of Mr/Ms versus Hcr/Hc, (Cowan et al., 2006; Day et al., 1977), suggesting magnetite is the dominant carrier of magnetic properties within Yakutat Terrane samples.

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35 Figure 2 1. Geologic terranes of southeastern Alaska, including the Chugac h Prince William and Yakutat Terranes. The Chugach and Prince William Terranes are lithologically similar and are considered a single terrane for the purposes of this study. Within the Chugach and Prince William Terranes lie the Valdez and Orca Groups (O VG), respectively, which represent mafic rocks (Plafker et al., 1994). The Yakutat Terrane is the youngest of the accreted terranes and can be divided into the Pamplona Zone (PZ) on the windward side of the St. Elias Range, and the Dangerous River Zone (D RZ). The PZ consists predominantly of the Kulthieth, Poul Creek and Yakataga Formations (Plafker et al., 1994). Table 2 1 Correlation coefficients for analyzed variables and grain size Values in parentheses are from this study. Variable % silt % clay Ce/Rb 0.205 + (0.773 + ) 0.198 ( 0.773 ) Cr/Al 0.201 + ( 0.072 + ) 0.086 (0.074) Ce/P ( 0.011) ( 0.009) Cr 0.152 ( 0.712) 0.088 (0.714 ) Ce 0.055 (0.545) 0.273 ( 0.543) Al2O3 0.022 ( 0.840 ) 0.245 (0.841 ) Fe203 0.186 0.389 MgO 0.175 + ( 0.788 + ) 0.119 (0.790 ) Mg/Al 0.118 (0.558) 0.187 (0.559) MS/FeO (0.270) ( 0.273) + significant at 0.01. r>0.6(modified from Dinelli et al., 2007).

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36 CHAPTER 3 METHODS Field Sampling M ethods Forty sediment samples from the Yakutat, Prince William, and Chugach Terranes were collected in the summer 2006 from rivers during peak runoff. In order to best represent the material predominantly transported to the GoA basin, mud samples were collected directly from the suspended sediment load of accessible river s draining directly from within the Chugach Terrane (Figure 2 1). When direct sampling was not possible, mud that had recently settled out of suspension (i.e., no mud cracks or other indications of drying) was collected from still pools adjacent to river banks. Analysis of the fine grained fraction of onshore sediments helps to ensure an accurate representation of the dominantly fine grained material that is delivered to the Surveyor Fan (Dinelli et al., 2007). In addition, sampling of fine grained sedi ments reduces the effects of sample dilution by common, stable minerals (i.e. quartz, feldspar) dominating the coarse size fraction, and by ameliorating sediment dilution effects, provenance tracers in trace element and mineral phases can be more readily i dentified (Dinelli et al., 2007). Collection of suspended sediment in rivers draining exclusively from Yakutat Terrane formations (Kulthieth, Poul Creek, Yakataga) was not logistically feasible, and so indurated samples were substituted. Samples of each f ormation were collected during 2006 by Ken Ridgway and students from Purdue University from various type localities within the Yakutat Terrane. In order to best represent each formation, samples were retrieved from lower, middle, and upper sections, and t hose collected from mud layers were selected for analysis. Samples from the Yakutat Terrane consist

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37 of consolidated offshore shelf sediments, and mud layers from these formations likely represent material that would be transported to GoA. A total of 62 10 cm 3 samples distributed throughout the entire hole depth were collected from various core sections from DSDP Site 178. Sample selection was done with specific focus on those samples bounding depths corresponding with strong seismic reflectors. Nearly all available samples from the uppermost core (10 samples; ~0 140 mbsf) were analyzed, while 20 samples from the middle and lowermost core (>140 mbsf) were more sparsely selected. Samples of core EW0408 85JC sediments were collected offshore from the shelf /slope break south of the terminus of Bering Glacier and used in order to represent the Orca/Valdez Groups (Barron et al., 2009; Figure 2 1). The jumbo piston core was sampled at approximately 10 cm intervals downcore, for a total of 109 samples. Aliquot s of all 85JC samples were analyzed for trace/major element geochemistry as well as magnetic susceptibility, while 16 selected samples were analyzed for mineralogy (Barron et al., 2009). Fifteen other samples were collected regularly downcore, and analyze d for magnetic hysteresis properties (Gillian Rosen, unpublished data). Initial Sample Preparation Aliquots of river samples, 85JC, and Site 178 samples were separated for use in rock magnetic, geochemical and X ray diffraction (XRD) analyses. Each aliquo t was dry sieved at 63 microns to separate fine fraction sediments. Yakutat Terrane samples were too indurated to properly disaggregate, and so they were crushed in a powdering box. Aliquots of this powder were used in all analyses. Future studies may c onsider a disaggregation technique used by E. Cowan ( personal communication ), in order to disaggregate indurated samples. Approximately 5 to 10 g of each sieved sample were

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38 loaded into non magnetic clear acrylic cubes for use in mass susceptibility analys is. These samples were then further divided for use in hysteresis and geochemical analysis, and, if sufficient sample mass was available, XRD and grain size analyses. Fine fractions were then analyzed for mass normalized magnetic susceptibility and magne tic hysteresis, trace/major element geochemistry and quantitative mineralogy. Analytical Techniques Samples were dried in a drying oven at 55C, and following initial sieving and separation, 5 10 g of fine fraction sediment (<63 microns) was measured a nd loaded into non magnetic plastic cubes (5.4 cm 3 ) for magnetic susceptibility analysis. This was performed on a Kappabridge KLY4 S and converted into mass normalized magnetic susceptibility (m 3 /kg) by normalizing to the concentration of dried sediment i n each cube. Following mass susceptibility measurements, samples were loaded into gelcaps (~200 milligrams ) for analysis of magnetic hysteresis properties. Hysteresis measurements were done on a MicroMag 3900 micro vibrating magnetometer (Princeton Measu rements Corp.) with an applied maximum field of 500 Oe. Analytical methods used in magnetic analysis of this study reproduce those employed in previous applications of environmental magnetic analysis in provenance investigation ( Liu et al., 2003 ; Cowan et al., 2006). Selected samples from Chugach Terrane, Yakutat Terrane, and Site 178 also were analyzed for both trace and major element geochemistry via ICP MS. Samples from Site 178 were selected in order to evaluate changes in elemental chemistry down c ore, with an emphasis on those samples near the depth representing 1 Ma. One set of samples intended for geochemical analysis was found to be contaminated with organic constituents during the acid digestion procedure, and so all samples used in

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39 geochemica l analyses were ashed at 550C to remove organic components prior to analysis. Errors in trace elemental analysis are less than + 5% for all elements (for further details in error analysis, see Kamenov et al., 2009). Major elements have a calculated error of < + 3%, which is smaller than symbols used on all bivariate plots. Sixty samples of onshore and offshore fine grained sediment were analyzed for mineralogy via XRD. Of these, thirty samples were analyzed on a Siemens D5000 Diffractometer at Universty of Colorado facilities. These samples were prepared with a 10% ZnO internal standard and homogenized using a McCrone Mill, then side mounted and analyzed at a step size of 0.02 degrees per step for 2 seconds per step from 5 65 done at University of Florida facilities was performed on a Rigaku Ultima IV diffractometer, using a Cu K alpha beam (1.5418 ) and focusing beam geometry. Samples were spiked with 20% corundum and spray dried in a polyvinyl alcohol solution to minimize preferred orientation of grains during sample loading, then top loaded into a sample holder and analyzed at a step size of 0.02 for 4 seconds/step from 5 mineralogy using JADE software (Rietveld r efinement). Silt and clay fraction particle size analysis was performed on selected samples from the Chugach Terrane and Site 178 (with emphasis on those samples near the lower bound of the UFS) using a Micrometrics Sedigraph 5000ET (e.g., Coakley and Syv itzki, 1991). Aliquots of these samples were sieved at 63 microns prior to analysis on the Sedigraph. Yakutat Terrane samples were not analyzed for grain size because they could not be successfully disaggregated while preserving original grain size of th e sedimentary material. (In future work, I suggest performing this by vacuum infusing

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40 samples with deionized water, then freezing to break up samples. This process can be repeated until all indurated sediments are disaggregated.) The correlation coeffic ient of grain size and all other variables was then determined and compared with those of Dinelli et al. ( 2007; Table 2 1).

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41 CHAPTER 4 RESULTS Mineralogical and Geochemical Analyses Results of all analyses performed in this study can be found in Appendice s A G All sample locations are shown in Appendix A. Appendix B contains the percent clay and silt within the fine fraction of the sediments. Chugach Terrane sediments have decreased clay percentages (with respect to Surveyor Fan sediments) and consist predominantly of silt. This is similar to lower and middle fan sequences, which have a high silt content. Upper fan sequence sediment, however, has the highest clay percentage of all samples, between 68 and 82 percent clay. Magnetic data are presented i n Appendix C and contain mass susceptibility measurements and the hysteresis properties H cr /H c and M r M s Among onshore terranes, the Kulthieth Formation exhibits the lowest magnetic susceptibility, as well as decreased H cr H c values relative to other Yakuta values similar to Kulthieth Terrane sediments, but exhibit significantly lower H cr /H c values compared to samples from the Yakutat Terrane as well as those from 85JC. Yakutat Terrane and 7 and 1.5x10 7 respectively, while Chugach Terrane sediments exhibit an order of magnitud e increase 6 ). All onshore terranes as well as Site 178 sediments exhibited high quartz, feldspar and muscovite contents ( Appendix D; Figure 4 1). Chugach Terrane samples, however, contain a greater amount of quartz than other terranes, with a mean quartz content of 40 percent, compared to 25.5 percent in the Yakutat Terrane. Mean feldspar and

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42 chlorite (clinochlore) content was similar among all samples, approximately 28 and 13 percent, respectively. Chugach Terrane, 85J C (Addison, 2009) and Site 178 sediments all had similar muscovite content (both in mean and standard deviation), which was slightly enriched relative to Yakutat Terrane sediments. Amphiboles were found in both on and offshore sediments, albeit inconsist ently. Kulthieth Formation sediments, however, contained no amphibole phases. All samples contained broadly similar concentrations of major oxides Ti, Ca, K, and P (Appendix E ). 85JC samples (as reported in Barron et al., 2009) exhibited decreased Al con tent relative to other onshore terranes, and P 2 O 5 abundance in 85JC samples lies between that of Chugach Terrane, which is enriched in P 2 O 5 and the Yakutat Terrane, which exhibits decreased phosphate abundance. The highest MgO content is exhibited by 85J C sediments, while Chugach and Yakutat Terrane samples have similar MgO abundance, with similar variation (St. Dev. = 0.47 0.76). Titanium oxide content is lowest and most invariant in 85JC samples, with a mean of 0.44 percent and standard deviation of 0. 03 percent. Chugach Terrane and 85JC sediments have decreased K 2 O abundance relative to Yakutat and Site 178 samples; however, the latter have an increased variability (Standard Deviation = 0.9 and 0.4 percent, respectively) Trace element compositions amo ng Chugach Terrane, Yakutat Terrane, and Site 178 samples are similar; however, 85JC samples are slightly enriched in Cr and V, but depleted in Y, Zr, Nb, Ba, Pb, Th, and U relative to other samples. Samples of 85JC also typically exhibit the lowest relat ive standard deviation among elemental ratios, which range from 0.10 to 0.29, compared to the Chugach and Yakutat Terranes, which

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43 range from 0.10 to 0.58 and 0.9 to 0.68, respectively (Appendix F ). All samples are enriched in LREE relative to HREE. 85JC sediments, however, are the most depleted in LREE elements, with average La and Ce content of 16.4 and 33.2 ppm approximately half that of Chugach Terrane sediments. Bivariate plots of absolute trace elemental abundances do not readily distinguish individ ual terranes; however, separation among onshore samples can be observed in trace and major elemental ratios. A plot of FeO versus FeO/Al 2 O 3 for example, exhibits three well resolved clusters of samples (Figure 4 2). All samples contain broadly similar a bundances of FeO, but are separated by varying FeO/Al 2 O 3 ratios. 85JC sediments exhibit the highest FeO/Al 2 O 3 content, while Kulthieth Formation samples have the lowest. This indicates that FeO/ Al 2 O 3 ratios are significantly high with respect to absolute FeO content in 85JC samples, but remains low in Kulthieth Formation sediment Intermediate to these two end members are samples from the Chugach Terrane, Poul Creek and Yakataga Formations, and samples from Site 178. Among Site 178 samples those sampl es from the middle and lower fan produce a broadly scattered cluster within a grouping of Poul Creek and Yakataga Formation samples. This scatter is significantly reduced in upper fan samples, which resolve into a small cluster. A plot of Cr/Al versus Mg/ Al ratios shows a positive linear correlation between the two variables among all sediment samples (Figure 4 3 ). Kulthieth Terrane sediments exhibit very low Cr/Al and Mg/Al ratios around 0.0005 and 0.1, respectively. Sediments from 85JC, however, exhib it the highest Cr/Al ratios, between 0.0015 and 0.003, as well as the highest Mg/Al ratios between 0.22 and 0.42. Samples from the Kulthieth

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44 Formation and 85JC sediments exhibit the greatest disparity on bivariate plots, while samples of the Chugach Terra ne typically lie between these two end members. These samples show a high coefficient of determination (R 2 =0.92) with a slope of 0.007. Sediments from the Poul Creek and Yakataga Formations, as well as those from the Surveyor Fan, however, also exhibit a linear correlation of decreased slope (0.002), indicating lower Cr/Mg ratios (with respect to Al). Samples of onshore terranes and 85JC sediments form well resolved clusters extending along a negative semi logarithmic regression line on bivariate plot s of Cr/Al versus Ce/P and Mg/Al ratios (Figure 4 3 A and B ). Samples of 85JC sediment exhibit the highest Cr/Al and Mg / Al ratios, but lowest Ce/P ratios, while Kulthieth Fm. are sediments from the Chugach Terrane, as well as Surveyor Fan and Yakutat Terrane sediments. While most samples are ind istinguishable within this region of the plot, those from the Yakutat block exhibit a transition in composition between the oldest Kulthieth, and the Poul Creek Fm., which exhibits slightly higher Cr/Al ratios and reduced Ce/P ratios relative to the Kulthi eth Fm, and finally to the Yakataga Formation, which plots closest to 85JC, with significantly high er Cr/Al and Mg/Al ratios and low Ce/P ratios relative to older Kulthieth sediment. Samples from upper and middle and lower fan sequence also exhibit mode st differentiation on bivariate geochemical plots. In addition to occupying regions of intermediate composition, samples from the upper fan sequence plot in distinct, well resolved clusters, while those from middle and lower fan sequences exhibit much gr eater scatter. The distinction in compositional variation can also be observed in

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45 downcore plots (Figure 4 4 and Table 4 1 ). While all fan sequences have similar mean elemental abundances and ratios, upper fan sequence samples exhibit an order of magnitu de decrease in relative standard deviation with respect to middle and lower fan sequences (Figure 4 5) Environmental Magnetic Properties Results of environmental magnetic analysis are consistent with previous studies investigating provenance of southeas tern Alaska sediments (Cowan et al., 2006). Samples from the Yakutat Terrane, as well 85JC exhibit an exponential trend extending from the MD region, through the PSD region, and through the SD region (Figure 4 6 ; Day et al., 1977). River samples from the Chugach Terrane are significantly distinct and form a scattered cluster with very low Hcr/Hc relative to other samples. These samples also exhibit a much wider range in Mr/Ms values between 0.05 and 0.6 m^3/kg, resulting in a cluster that does not exist within any of the defined domain regions. Material collected from Site 178 form a loosely resolved cluster lying between Yakutat Terrane and Chugach Terrane sediments. Those samples that lie within the well resolved cluster of Yakutat Terrane sediments a lso lie along, or very near to the theoretical magnetite mixing continuum, while several samples from Lower Middle and Upper Fan sequences exhibit much more scatter, and plot within the poorly resolved Chugach Terrane cluster. On a plot of FeO 4 7). Chugach Terrane samples form a well 3.0x10 8 and 7.6x10 7 These samples have a similar range to sediments from the Yakutat Terrane and 85J C, which form another cluster with significantly higher Hcr/Hc, 8 and 2.9x10 7 Sediments found at Site 178,

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46 5 and 3.3x10 6 and Hcr/Hc values that span both clusters of onshore terrane samples. other fan sequences, while a broad range in Hcr/Hc values is exhibited by samples throughout Site 178, and is not limited to a ny particular fan sequence. Samples exhibiting a higher clay percentage (Kulthieth Terrane, Upper Fan Sequence) also y samples from the Yakutat Terrane and Site 178. Chugach Terrane river sediments exhibit low MS/FeO values, even in samples with low clay percentages.

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47 Figure 4 1. Sediment mineralogy. While sample mineralogy exhibits considerable scatter, onshore s ediments exhibit broad similarities in mineral composition, particularly in feldspar and chlorite abundance.

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48 Figure 4 2. Percent FeO versus FeO/Al2O3 ratios. Dotted lines represent fields of average parent rock composition. Basalt composition is fro m Schilling et al. (1983); pegmatite composition is from Antunes et al. (2008), and shale composition is from Mannan (2002). 85JC data are from Barron et al. (2009). Sediment samples plot in three distinct clusters, and exhibit a positive correlation bet ween FeO and FeO/Al2O3 ratios. While all samples have similar absolute FeO abundance, Kulthieth Formation samples exhibit thelowest FeO/Al2O3 ratios. These ratios are highest in 85JC sediments. Chugach Terrane, Poul Creek and Yakataga Formation, and Sit e 178 sediments occupy an intermediate region between Kulthieth and 85JC samples.

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49 Figure 4 3. Cr/Al versus Ce/P and Mg/Al ratios. A) Samples from 85JC exhibit the highest ratios of Cr/Al, along with the lowest P normalized trace element abundance (Ce/P). Kulthieth samples, however, have the lowest Cr/Al ratios, while exhibiting the highest ratio of P normalized Ce. B) 85JC samples have consistently low REE values relative to P. A high abundance of heavy elemental ratios (Cr/Al) and low trace element abundance, with respect to P, indicate a more mafic composition.

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50 Figure 4 4. Downcore plots of grain size, elemental, and magnetic data. Samples with SF label (e.g., SF 01) represent samples collected from core segments of Site 178. For specific sample depth intervals, refer to Appendix A. Samp les from Site 178 exhibit a high variability in composition of middle and lower fan sequences that decreases in upper fan sequence samples. This is supported by an order of magnitude decrease in standard deviation between lower and upper fan sequences (T able 3). The mean values of all compositional variables remain the same, however.

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51 Table 4 1 Mean and standard deviation values of Site 178 compositional variables. Mean values are typically similar between upper and lower fan sequence samples Standard deviation of most variables decreases by an order of magnitude in upper fan sequence, relative to middle and lower fan sequence samples. Mean Relative St. Dev. Percent Clay 7.4E+01 ** 6.8E 02 ** 4.4E+01 5.0E 01 Mg/Al 2.6E 01 ** 8.0E 02 ** 2.7E 01 2.1E 01 Fe/Al 6.4E 01 ** 2 6 E 02 ** 6.5E 01 1.9E 01 FeO 6.3E+00 ** 1.0 E 01 ** 5.5E+00 2.0 E 01 MgO 3.8E+00 ** 6.1E 02 ** 3.4E+00 2.4E 01 Ce/P 4.5E 02 ** 1.0E 01 ** 4.6E 02 2.2E 01 Cr/Al 1 .3E 03 ** 7.7E 02 ** 1.2 E 03 1.8E 01 (m3/kg) 5.3E 07 ** 1.3E 01 ** 8.8E 07 8.0E 01 **upper fan sequence.

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52 Figure 4 5 A Day plot of hysteresis properties of southeastern Alaska sediments. Samples from the Yakutat Terrane and 85JC extend exponentially from MD region to the SD region (separated by dashed lines), following a theoretical magnetite mixing curve as defined by Day et al. (1977). Samples from the Chugach Terrane do not adhere to this theoretical mixing line, instead exhibiting extremely low Hcr/Hc values and a bro ad range of Mr/Ms values. Site 178 sediments, however, are scattered between Yakutat Terrane samples and Chugach Terrane samples.

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53 CHAPTER 5 DISCUSSION Mineralogical and Elemental Analyses The only major distinction in mineralogy observable among all samples is in the abundance of quartz (Figure 4 1; Appendix D ). Chugach Terrane samples as well as those of the lower fan sequence have the highest abundance of quartz; however, these samples a lso exhibit the lowest percentage of clay. This suggests that the high quartz abundance may be attributed to the coarser grain size, and perhaps does not necessarily represent a characteristic of original source rock composition. Because common mineral p hases such as quartz and feldspar dominated the mineralogy, other trace mineral phases (e.g., apatite and monazite) could not be easily quantified via XRD analysis and Rietveld refinement. However, all samples have similar abundances of chlorite (clinochl ore) and muscovite mineral phases (excluding Kulthieth Formation samples), which are readily altered to more stable clay mineral phases such as illite, kaolinite, and smectite. This suggests that these samples have undergone minimal to very moderate amoun ts of weathering (Figure 4 1; Nesbitt and Young, 1996; Nesbitt et al., 1996; Marinoni et al., 2008). Geochemical variables applied to characterization of onshore terranes and provenance of Site 178 in this study were chosen based on their potentially low influence by sedimentary processes that may mask true compositional signals from source terranes (e.g. McLennan et al., 1993), including physical sorting of sediments resulting in preferential composition attributed to grain size (McLennan et al., 2003, 1 993; Dinelli et al., 2007; Bhatia and Crook, 1986). Many absolute elemental abundances, while relatively immobile in sediments during chemical weathering, have

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54 been found to be affected by physical sorting processes as certain mineral phases are preferent ially fractionated out (Bhatia and Crook, 1986; Dinelli et al., 2007). For this reason, geochemical ratios that are believed to be the most useful in determination and differentiation of original composition of onshore and offshore sediments include Cr/Al Mg/Al, Ce/P, and FeO/Al 2 O 3 (Table 2 1). Samples from 85JC contain the highest Fe, Cr, and Mg abundances with respect to Al (Figure 4 3 for Cr and Mg abundances; Figure 4 2 for Fe). This suggests that there is a greater abundance of mineral phases bear ing these elements (i.e. Fe bearing clays, chromite, monazite, apatite) than there are in Kulthieth Formation sediments, which exhibit the lowest Fe, Cr, and Mg abundances and a more felsic composition (Signh and Gilkes, 1991). This suggests that 85JC sed iments are more mafic in composition, relative to Kulthieth Formation sediments. While the Kulthieth Formation and 85JC sediments are suggestive of two end member compositions, Chugach Terrane, Poul Creek, and Yakataga Formation sediments yield compositio ns that lie between 85JC and Kulthieth Formation samples. This implies that material from the Chugach Terrane and Poul Creek and Yakataga Formations are a mixture of felsic and mafic constituents. In addition to other trace and major elemental constituen ts, REEs such as Ce commonly substitute into phosphate mineral phases such as monazite, and apatite, which are often trace mineral constituents not detected in XRD analysis (McLennan et al., 2003; Dinelli et al., 2007). Low Ce abundance normalized to P, e xhibited by 85JC sediments (Figure 4 3B), suggests that there is an abundance of P bearing mineral phases into which REE substitute. This abundance of P relative to Ce would result in

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55 decreased Ce/P ratios. This is not seen in Kulthieth Formation sedimen ts, which exhibit the highest P normalized REE abundance. The abundance of P and higher Ce/P ratios support the presence of apatite and monazite (two minerals associated with mafic material) in 85JC sediments. In contrast, these ratios suggest that Kulth ieth Formation contain a low abundance of apatite or monazite and are likely the most felsic of analyzed samples, while those sediments from the Chugach Terrane, Poul Creek and Yakataga Formations, and Site 178 sediments, a re of an intermediate co mposition, having Ce/P, Cr/Al, and Mg/Al ratios between those of the Kulthieth Terrane and 85JC sediments. Environmental Magnetic Properties Results of this study are consistent with those of Cowan et al. (2006), suggesting that the same phases are contrib uting to the magnetic signature in both sand and fine fraction sediments (Figure 4 6). Here, the Chugach and Yakutat Terrane samples exhibit two very distinct clusters, with significantly lower and higher H cr /H c values, respectively. In addition, Chugac h Terrane sediments exhibit a greater range in magnetic remanence (M r /M s ) values than do samples from 85JC and Yakutat Terrane. Samples from the Yakutat Terrane, 85JC, and Surveyor Fan samples all plot close to the theoretical magnetite mixing line; howe ver Surveyor Fan samples display more scatter and several points plot within the Chugach Terrane region. The fact that they plot close to the theoretical magnetite mixing line suggests that magnetite is the likely magnetic carrier within samples from the Yakutat Terrane and 85JC. Western Chugach Terrane samples, however, exhibit considerable scatter on a Day plot, with very low Hcr/Hc values, and a broad range in Mr/Ms values. Very few of these samples lie along

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56 the theoretical magnetite mixing continuum suggesting that magnetite is not the dominant magnetic carrier within western Chugach Terrane sediments. Determination of these magnetic mineral phases was below the detection limits of XRD analysis (<1 percent) due to dilution by silicate minerals, bu t evidence from Cowan et al. (2006) suggests that magnetite is absent from sand sized Chugach Terrane sediments, and instead, pyrrhotite (FeS) acts as the dominant magnetic mineral phase. This determination is based upon thorough magnetic extraction and l ow temperature remanence analysis, which revealed no magnetite verwey transition in Chugach Terrane sediments (Cowan et al. 2006). Pyrrhotite typically exhibits very low H cr /H c with moderate M r /M s ( Clark, 1984; Dekkers, 1988; Hounslow and Maher, 1996; Di reen et al., 2000). Chemical Weathering The Chemical Index of Alteration, as discussed above, is useful in determining the relative degree of chemical alteration of sediment but cannot be applied in this study, because the ICP MS analysis of major element chemistry did not include Si or Na (prevented by dissolution of Si, and seawater contamination of the apparatus during analysis, respectively). Future analysis via XRF may provide these elements and yield more versatile major elemental geochemical analys es. Interpretation of Sedimentary Provenance Compositional variation that can be caused by physical sorting of sediments is circumvented in this study by employing established elemental provenance tracers that are immobile and relatively independent of g rain size (Taylor and McLennan, 1982; Bhatia and Crook, 1986; McLennan et al., 2003; Dinelli et al., 2007). Distinction between sources is exhibited in the relationships between major elements Al and Fe.

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57 On a plot of FeO/Al 2 O 3 versus FeO (Figure 4 2 ), a positive correlation is a result of a particular parent rock composition, as indicated by fields of basaltic and pegmatitic composition, based on average compositions from Melson et al. (1976) and Schilling et al. (1983). These fields have respective ly high and low FeO/Al 2 O 3 ratios, which produce a positive linear trend in composition. Average shale composition from Mannan (2002) lies in a field of intermediate composition between these two. All samples have similar FeO abundance, which is similar t o the FeO abundance found in average shales. The high and low FeO/Al 2 O 3 ratios of 85JC and Kulthieth Formation sediments, respectively, may be explained by the types of clay minerals present. In samples of similar grain size such as those in this study, Fe bearing clays, such as chlorite or smectite would reduce the abundance of Al relative to Fe, and result in higher FeO/Al 2 O 3 ratios in mafic materials. Aluminum bearing clays found in felsic material, such as muscovite, illite, and kaolinite would have the opposite effect, reducing FeO/Al 2 O 3 ratios. Samples of Chugach Terrane, Poul Creek and Yakataga Formations, and Surveyor Fan sediments likely represent a mixed composition and so retain intermediate FeO/Al 2 O 3 ratios. These variations in FeO/Al 2 O 3 ra tios with respect to Fe abundance suggest that 85JC represents a mafic composition relative to other onshore terranes, while Kulthieth Formation sediments are of a relatively felsic composition. Geochemical, Mineralogical and Magnetic Characterization of O nshore Terranes Because core 85JC is found along the sediment dispersal route from the Bering Glacier, it is assumed that samples from this core adequately capture the primary provenance signal from the Bering (Figure 1 1 ). T race and major elements ratios within 85JC samples are consistently high in all bivariate plots, relative to other analyzed terranes. The strongly mafic composition of the samples is presumed to be derived from

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58 the Late Cretaceous Paleocene Orca/Valdez Groups (OVG; Plafker et al., 1994; ), which underlies the Bagley Ice field from which the Bering Glacier sources and for purposes of this study will hereafter be referred to as Orca/Valdez Group (OVG) sediments. These groups lie to the north of the St. Elias Range and are composed of high grade meta morphosed flysch deposits altered from lithic wacke as well as basaltic units (Plafker et al., 1994). Obducted oceanic crustal components are also present within this suite of rocks, suggesting that the presence of mineral phases associated wit h mafic material resulted in the observed mafic geochemical signature of 85JC samples The 85JC samples derived from OVG and the Kulthieth Formation exhibit the most geochemical and mineralogical distinction of any of the analyzed onshore terranes. This suggests that these represent end members in composition, while other terrane constituents, such as the Poul Creek and Yakataga Formations and western Chugach Terrane, carry an intermediate composition. This composition, however, does not imply the same p rovenance history for the Chugach Terrane and Poul Creek and Yakataga Formations, and will be discussed below. River samples from the western Chugach Terrane exhibit transitional compositions that consistently produce well resolved clusters (Figures 4 1 th rough 4 3) and represent material that appears to be a mixture of felsic and mafic components. Material from the westernmost Chugach Terrane has undergone zero to moderate grade metamorphism and consists predominantly of lithic greywacke (Plafker et al., 1994). The Chugach Terrane was likely deposited as the Kula Plate subducted underneath British Columbia, and, therefore, reflects derivation from continental arc volcanics ( Cowan, 1982; Plafker,

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59 1987; Plafker et al., 1994). The transitional composition o f the westernmost Chugach Terrane is likely a product of direct derivation from a source that is of an intermediate composition, rather than a mixing of any end member sources, and certainly does not reflect a transition in provenance signature from contem porary OVG to younger Kulthieth Formation sediments. In contrast to OVG and Chugach sediments, the Kulthieth Formation within the Yakutat Block is composed of offshore outer shelf/slope deposits that have undergone no significant metamorphism ( Moore, 197 3 ; Plafker et al., 1994). An aluminous, felsic composition of Kulthieth Formation constituents is reflected in both the geochemistry and mineralogy. Trace and major elemental geochemistry reveals a greater abundance of elements associated with felsic mat erial such as Al, and a low concentration of elements relative to other onshore terrane samples ( 85JC Chugach Terrane ; Figure 4 3 ). The Poul Creek and Yakataga Formations are geochemically similar to the Chugach Terrane in that these formations both repr esent a composition transitional between mafic and felsic end members Elemental data from both formations occupy a region between the Kulthieth Formation and OVG on all bivariate plots, with few outliers. Yakataga Formation sediments represent sediment deposited offshore in an outer shelf/slope environment, similar to that of the Kulthieth (Plafker et al, 1994); however, these formations were deposited later in the accretionary history of the Yakutat Terrane microplate suggesting that the offshore depositional basin was being supplied with sediment from the coastal mountains that contain Chugach Terrane material (Lagoe et al., 1993; Haeussler, 2004).

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60 Site 178 Sediment Provenance Core samples from Site 178 are composi tionally most similar to western Chugach Terrane sediments, occupying a region between Kulthieth Formation sediments and OVG on all geochemical bivariate plots and containing similar mineralogy. This suggests that Site 178 samples are of a transitional co mposition between mafic and felsic end members and that these sediments were derived from either a mixture of OVG (as expressed by 85JC) and Kulthieth Formation sources, or directly sourced from an area with a composition similar to the western Chugach Ter rane. Environmental magnetic properties help to resolve this distinction, in that the majority of Site 178 samples within all fan sequences exhibit magnetic characteristics of both Yakutat and western Chugach Terranes. On a Day plot, the majority of samp les within each fan sequence lie consistently along the theoretical magnetite mixing line; however, several samples from upper middle and lower fan sequences are scattered within the region occupied by Chugach Terrane samples. This suggests that the m agnetic carrier within Site 178 samples is variable, dominated by magnetite in most samples, and another magnetic carrier (e.g. pyrrhotite) in others. In addition, Site 178 samples all occupy a region spanning Chugach Terrane and Yakutat Terrane clusters on a plot of Fe cr /H c (Figure 4 7). Had Site 178 sediments been derived entirely from western Chugach Terrane sources, hysteresis properties would have been consistent with only those of the Chugach Terrane (i.e. low H cr /H c low to high M r /M s ), whereas derivation entirely from Yakutat Terrane would imply that all samples would contain magnetite, and therefore lie along the magnetite mixing continuum.

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61 Evidence for a MPT Change In Onshore Sediment Production Determining a change in pr ovenance between sediments of the uppermost fan sequence (post MPT) and those of the middle and lowermost fan sequences (pre MPT) is ambiguous, as all Surveyor Fan samples have similar geochemical, magnetic, and mineralogic composition. In addition, uppe r fan sequence sediments are closely correlated in well resolved clusters in bivariate geochemical plots, and similar compositional behavior can be observed in plots of downcore composition (Figure 4 5). In these plots, many elements and elemental ratios, as well as grain size, exhibit a large standard deviation in middle to lower fan sediments, but have a consistent composition (low standard deviation) in sediments of the upper fan. This implies that, while all fan samples are compositionally a mixture of mafic and felsic material (likely Chugach and Yakutat Terranes), those of the upper fan (post MPT) are transported from a narrowed locus of sources, producing more constant elemental ratios and abundances. The change from more variable elemental, mine ralogical, and magnetic composition in lower and middle fan sequences, to a more constant composition of the upper fan sequence (Figure 4 5), supports the hypothesis that following the 1 Ma Mid Pleistocene Transition, the sediment transport pathway supply ing material to the Surveyor Fan became more focused, but which derived sediment from a mixture of source terranes. This focusing of the sediment dispersal pathway following the MPT reflects the creation of cross shelf sea valleys, which likely developed due to significant scouring during this period of accelerated glacial advance (Reece, 2009; Mayer et al., 2005). Exhumation models of both Enkelmann et al. (2009) and Berger et al. (2008) suggest that the locus of accelerated exhumation shifted at ~ 1 2 Ma from the Chugach

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62 Terrane, south toward the windward side of the St. Elias range, which is dominated by Kultieth, Poul Creek, and Yakataga Formations (A 1). However, the mixed composition of Chugach, Poul Creek, and Yakataga terranes and Site 178 upper fan sequence samples as determined from these analyses does not allow for definitive identification of the onshore sediment sources supplying the UFS at the distal location of Site 178 based on analyses of the bulk fine grain fraction.

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63 CHAPTER 6 CONCLUSIONS The intention of this study was to test the hypothesis that the MPT resulted in a change in se dimentation on the Surveyor fan caused by the localized intensification of glacial erosion and exhumation along the windward side of the St. Elias Range. Testing this hypothesis requires establishing the provenance tools most useful for characterizing com positional differences in onshore source terranes, and applying these tools in establishing a provenance history of offshore sediment samples from DSDP Site 178. I hypothesized that this southward transition and significant acceleration of exhumation resu lted in a focusing of erosion to the windward side of the St. Elias range was accompanied by isolation of a sediment transport pathway to the Surveyor Channel as glacial advance s following the MPT scoured the present cross shelf sea valleys. In addition, it is hypothesized that these variations in sediment production and transport would be represented by a change in composition of Surveyor Fan sediments to sediments derived from the rapidly exhuming rocks. All bulk fine grain onshore terrane and S ite 178 samples exhibit similar mineralogy, with abundant quartz, feldspar and muscovite, as well as unaltered minor mineral phases such as amphiboles, chlorite (clinochlore) and muscovite (with the exception of the Kulthieth Formation, which lacks amphibo le minerals). The presence of these minor minerals suggests that these sediments have undergone little alteration, and therefore little post erosional chemical weathering. Elemental ratios that are independent of grain size and also discriminatory among o nshore terranes include Cr/Al, Mg/Al, and Ce/P ratios. On bivariate plots of thes e

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64 ratios, onshore terranes separate into three distinct clusters. Sediments from core 85JC, presumed to represent sediment derived directly from the Bering Glacier, exhibit the highest ratios of heavy elemental constituents such as Fe/Al 2 O 3 Cr/Al, and Mg/Al, suggesting that these sediments are derived from mafic onshore sources. This is also supported by Ce/P ratios, which are reduced due to the presence of heavy phosphates such as monazite and apatite. For these reasons, I conclude that 85JC sediments are derived principally from mafic rocks within the Orca and Valdez Groups (OVG) of the Chugach Terrane. Antithetical to this composition is that of Kulthieth Formation samp les. These sediments have the lowest Al normalized heavy element ratios (FeO/Al 2 O 3 Cr/Al, Mg/Al), as well as the highest Ce/P ratios, implying a low abundance of heavy mineral phases and a felsic composition. Both Kulthieth Formation and OVG sediments exhibit environmental magnetic properties that indicate magnetite is the dominant magnetic carrier, as opposed to other ferrimagnesious minerals such as pyrrhotite. Samples from the western Chugach Terrane, as well as sediments from the Poul Creek and Yaka taga Formations are of an intermediate composition. All elemental ratios of these sediments are between those of OVG and Kulthieth Formation sediments, which suggests that Chugach Terrane and Poul Creek and Yakataga Formation material are all of a transit ional composition between felsic and mafic. Chugach Terrane sediments also exhibit unique magnetic properties. These sediments have extremely low H cr H c values, and a broad range in M r /M s values, indicative of pyrrhotite. These coercivity and remanence va lues help to distinguish Chugach Terrane material from Poul Creek/ Yakataga sediments, which have similar elemental

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65 compositions, but distinctly different magnetic properties. The transitional nature of elemental ratios in Chugach Terrane sediments is lik ely due to the composition of original flysch deposit sediments, while in Poul Creek and Yakataga Formations, this composition could reflect the mixing of felsic and mafic material derived from existing accreted units (e.g. Kulthieth Formation and Orca Gro up, respectively) The Poul Creek and Yakataga may also be able to be further separated into two distinct units compositionally, and a provenance history can be delineated, as the Poul Creek samples tend to plot closer to Kulthieth sediments on bivariate plots of elemental ratios, while samples from the Yakataga Formation often lie closest to 85JC sediments, indicating a more mafic influence. Samples collected from DSDP Site 178 exhibit elemental ratios (FeO/Al 2 O 3 Cr/Al, Mg/Al, Ce/P) that are between thos e of OVG and Kulthieth Formation sediments, and are similar in composition to Chugach Terrane. This suggests that these samples are either principally derived from the Chugach Terrane, or a mixture of felsic and mafic end members (OVG and Kulthieth Format ion). Environmental magnetic properties of these sediments exhibit behavior that is indicative of both Chugach and Yakutat Terranes, suggesting that Site 178 samples are a mixture of onshore sources. Distinguishing changes in source composition within Si te 178 samples is ambiguous; however, samples from the upper fan sequence produce small, well resolved clusters in bivariate plots of elemental ratios of this study, whereas those samples from middle and lower fan sequences exhibit much greater scatter. T his is consistent with downcore plots of elemental ratios that show high standard deviations in middle and lower fan sequences, but very low standard deviations of upper fan

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66 sequence composition. Minimal variation in the composition of upper fan sequence s suggests the transport pathway to the Surveyor Channel was focused to a specific source area following the MPT. This is consistent with the timing of the formation of current cross shelf sea valleys dispersing sediment to the Surveyor Channel. Because o f the compositional and mineralogical similarity of the bulk fine grain samples analyzed in this study, it is not possible to clearly delineate how specific terranes are supplying sediment to the Surveyor Fan at the location of Site 178, or if there is mix ed provenance Consequently, it remains unclear as to whether the offshore sedimentary record can resolve if there was a shift in the erosional front during accelerated exhumation. In order to differentiate the composition of specific regions within ons hore terranes, such as the Orca and Valdez Groups, it is necessary to obtain sediment samples directly from these sources, rather than indirect sampling of derivative material such as 85JC sediments. Drilling in more proximal locations in the northern Gul f of Alaska, such as along the shelf, and within the Surveyor Channel would also provide access to sediments that have undergone even less transport than those at Site 178, suggesting that they may be more representative of onshore terranes while still pre serving variation in sediment production and transport. In addition, mineralogical and geochemical analysis of the separated clay and silt fractions may provide greater insight into the erosional, weathering, and transport processes, as the silt fraction contains mostly rock forming minerals Elemental analysis via X ray Fluorescence (XRF) would also provide major elemental abundance that includes constituents such as Na and Si that were not obtained through ICP MS analysis in this study. These methods w ould provide greater

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67 precision in differentiating onshore and offshore terranes, and thereby help to define a clearer relationship between offshore deposition and onshore sediment production.

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68 APPENDIX A SAMPLE LOCATIONS Table A 1. Chugach River Sample L ocations Sample ID Location Name Latitude (N) Longitude (W) Degrees Minutes Degrees Minutes CHU 01 Mile Two Creek Nash 60 8.5 149 24.78 CHU 02 Resurrection River #1 60 9.93 149 28.77 CHU 03 Exit Glacier 60 11.04 149 37.65 CHU 04 Snow River 60 20.05 149 20.96 CHU 05 Victor Creek 60 22.58 149 20.83 CHU 06 Falls Creek 60 25.87 149 22.1 CHU 07 Sterling Highway 1 60 29.54 149 48.47 CHU 08 Sterling Highway 2 60 31.37 150 11.72 CHU 09 Quartz Creek 60 35.72 149 32.63 CHU 10 Six Mile Creek 60 38.54 149 29.83 CHU 11 Bertha Creek 60 43.65 149 17.05 CHU 12 Six Mile Creek East Fork 60 46.83 149 25.61 CHU 13 Lyons Creek 60 46.73 149 13.15 CHU 14 Placer River 60 49.19 148 59.88 CHU 15 Upper Portage Creek 60 49.24 148 58.36 CHU 16 Twenty Mile River 60 50.7 148 58.93 CHU 17 Ingram Creek 60 50.8 149 3.38 CHU 18 Glacier Creek 60 56.32 149 9.89 CHU 19 Bird Creek 60 58.45 149 27.77 CHU 20 Lowe River 61 3.66 145 59.58 CHU 21 Sheep Creek 61 6.73 145 48.66 CHU 22 Worthington Glacier 61 10.14 145 42.97 CHU 23 Tsiana River 1 61 11.74 145 33.14 CHU 24 Tsiana River 2 61 12.51 145 24.36 CHU 25 Tiekel Creek 61 19.78 145 18.29 CHU 26 Little Tonsina Creek 61 35.92 145 12.66 CHU 27 Tonsina River 1 61 39.78 145 10.83 CHU 28 Tonsina River 2 61 38.99 144 39.09 CHU 29 Klutina River 61 57.13 145 18.25 CHU 30 Tazlina River 62 3.39 145 25.42 CHU 31 Stuart Creek 61 16.83 145 16.43 CHU = Chugach Terrane

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69 Table A 2. Yakutat Terrane Sample Locations Sample ID Latitude (N) Longitude (W) Degrees Minutes Degrees Minutes Lower Kulthieth (KTL) 60 9.54 140 39.33 Middle Kulthieth (KTM) 60 26.47 150 6.66 Upper Kulthieth (KTU) 60 20.66 142 36.68 Lower Poul Creek (PCL) 60 14.45 144 19.78 Middle Poul Creek (PCM) 60 3.81 142 25.28 Upper Poul Creek (PCU) 60 3.00 141 53.57 Lower Yakataga (YKL) 59 49.04 144 31.96 Midle Yakataga (YKM) 60 10.21 149 22.33 Upper Yakataga (YKU) 60 7.60 148 54.69 Table A 3. Surveyor Fan Core Sample Intervals Sample ID Core Section Meters Below Sea Floor Sampling Interval (cm) SF_01 1 1 0 1.5 104 106 SF_02 1 1 0 1.5 140 142 SF_03 2 3 12 15 7 8 SF_04 2 3 12 15 50 52 SF_05 2 3 12 15 112 114 SF_06 4 1 24 25.5 52 54 SF_07 4 1 24 25.5 110 112 SF_08 4 1 24 25.5 130 132 SF_09 15 1 123 124.5 52 54 SF_10 15 1 123 124.5 56 58 SF_11 15 1 123 124.5 110 112 SF_12 15 1 123 124.5 140 142 SF_13 26 1 220.5 221.5 10 12 SF_14 26 3 220.5 221.5 64 66 SF_15 26 3 220.5 221.5 71 73 SF_16 26 3 220.5 221.5 85 87 SF_17 26 3 220.5 221.5 130 132 SF_18 29 2 249 258.5 10 12 SF_19 29 2 249 258.5 38 40 SF_20 29 2 249 258.5 88 90 SF_21 29 2 249 258.5 130 132 SF_22 33 4 315.5 325 1 3 SF_23 33 4 315.5 325 40 42

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70 Sample ID Core Section Meters Below Sea Floor Sampling Interval (cm) SF_24 33 4 315.5 325 59 61 SF_25 33 4 315.5 325 89 91 SF_26 33 4 315.5 325 139 141 SF_30 37 2 353.5 363 80 82 SF_31 37 2 353.5 363 109 111 SF_32 37 2 353.5 363 130 132 SF_33 37 2 353.5 363 132 134 SF_34 43 1 446.5 456 25 27 SF_35 43 1 446.5 456 58 60 SF_36 43 1 446.5 456 143 145 SF_37 43 1 446.5 456 100 102 SF_38 44 5 456 465.5 7 9 SF_39 44 5 456 465.5 60 62 SF_40 44 5 456 465.5 95 97 SF_41 44 5 456 465.5 114 116 SF_42 44 5 456 465.5 133 135 SF_43 44 5 456 465.5 135 137 SF_44 47 1 505.5 515 105 107 SF_45 47 1 505.5 515 119 121 SF_46 47 1 505.5 515 134 136 SF_47 47 1 505.5 515 143 145 SF_48 48 1 534 543.5 20 22 SF_49 48 1 534 543.5 32 34 SF_50 48 1 534 543.5 54 56 SF_51 48 1 534 543.5 65 67 SF_52 48 1 534 543.5 100 102 SF_53 48 1 534 543.5 110 112 SF_54 49 1 591 600.5 80 82 SF_55 49 1 591 600.5 114 116 SF_56 49 1 591 600.5 143 145 SF_57 49 1 591 600.5 146 148 SF_58 51 1 657.5 667 110 112 SF_59 51 1 657.5 667 122 124 SF_60 51 1 657.5 667 146 148 SF_61 53 1 716 720 22 24 SF_62 53 1 716 720 67 69

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71 APPENDIX B FINE FRACTION GRAIN SIZE ANALYSIS Table B 1. Percent Clay, Chugach Terrane and Surveyor Fan. Sample % Silt % Clay Mean sortable silt St. Dev. sortable silt Chugach Terrane CHU 02m 85.3 14.0 23.6 1.5 CHU 03m 65.5 33.5 26.9 1.5 CHU 14m 73.5 24.4 34.8 1.4 CHU 16m 83.9 14.8 31.1 1.4 CHU 17m 74.2 25.6 23.3 1.4 CHU 18m 74.7 24.4 24.6 1.6 CHU 19m 69.2 30.5 20.3 1.5 CHU 20m 82.7 16.8 20.1 1.5 CHU 21m 75.0 24.8 17.4 1.4 CHU 22m 80.0 19.8 20.0 1.5 CHU 23m 85.8 13.7 21.4 1.5 CHU 24m 80.7 18.6 23.1 1.5 CHU 31m 82.0 17.3 22.1 1.6 UFS SF 01 29.8 69.8 16.1 1.5 SF 02 27.4 72.4 17.7 1.5 SF 03 27.8 71.9 18.0 1.5 SF 05 31.4 68.4 15.2 1.4 SF 08 24.4 75.4 16.9 1.5 SF 09 18.5 81.2 15.8 1.5 SF 10 19.2 80.5 16.3 1.5 MFS SF 12 25.0 74.7 15.8 1.5 SF 15 69.9 29.8 17.8 1.5 SF 18 84.3 15.4 19.2 1.5 SF 20 59.3 40.4 17.5 1.5 SF 21 68.3 30.8 25.2 1.6 SF 22 16.0 83.7 18.2 1.7 SF 23 25.8 73.9 18.7 1.6 SF 28 63.4 36.0 23.6 1.6 SF 29 64.8 35.0 20.0 1.5 SF 31 75.8 23.6 24.1 1.6 LFS SF 33 59.9 39.5 24.6 1.6 SF 37 38.4 61.4 17.8 1.5 SF 40 72.0 27.0 29.3 1.5 Note: UFS=Upper Fan Sequence, MFS=Middle Fan Sequence, LFS=Lower Fan Sequence

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72 APPENDIX C ENVIRONMENTAL MAGNETIC PROPERTIES Table C 1. Environmental Magnetic Properties Sample Mass Susc. (m3/kg) Mr/Ms Hcr/Hc Chugach Terrane CHU 03m 4.61E 07 0.27 0.49 CHU 14m 1.54E 06 0.07 0.22 CHU 15m 6.32E 07 0.06 1.05 CHU 16m 1.58E 06 0.09 0.63 CHU 17m 1.25E 06 0.11 1.23 CHU 18m 2.67E 07 0.17 0.83 CHU 19m 1.69E 06 0.10 1.94 CHU 20m 2.31E 07 0.28 0.18 CHU 21m 2.11E 07 0.58 0.96 CHU 22m 1.64E 07 0.67 0.83 CHU 23m 1.76E 07 0.48 0.15 CHU 24m 1.56E 07 0.55 0.17 CHU 25m 3.62E 07 0.11 0.26 CHU 29m 3.05E 06 0.09 0.62 CHU 30m 3.63E 06 0.08 1.82 Yakutat Terrane KTL 01 1.45E 07 0.12 3.44 KTL 02 1.16E 07 0.13 3.33 KTM 01 1.02E 07 0.23 3.92 KTM 02 2.13E 07 0.06 5.85 KTU 02 1.10E 07 0.13 3.72 KTU 03 1.56E 07 0.11 3.74 PCL 01 2.68E 07 0.08 5.00 PCL 02 3.18E 07 0.07 5.00 PCM 02 1.63E 06 0.11 3.96 PCM 03 1.20E 06 0.09 3.68 PCU 02 1.05E 06 0.04 7.34 PCU 03 3.73E 07 0.07 4.62 YKL 01 7.68E 07 0.05 6.77 YKL 02 4.40E 07 0.06 4.84 YKM 01 5.46E 07 0.06 6.04 YKM 02 6.93E 07 0.08 5.53 YKM 03 1.02E 06 0.10 4.41 YKU 01 7.18E 07 0.08 4.02 YKU 02 8.61E 07 0.08 3.79 EW0408 85 JC 10 3.19E 07 19 3.45E 07 0.11 3.15 29 3.36E 07 40 4.02E 07 49 4.41E 07 60 4.66E 07 70 4.69E 07

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73 Sample Mass Susc. (m3/kg) Mr/Ms Hcr/Hc 80 5.31E 07 100 5.83E 07 108 6.06E 07 0.08 3.51 120 5.32E 07 128 4.29E 07 138 3.67E 07 150 3.21E 07 158 3.30E 07 170 3.27E 07 0.10 3.10 178 3.27E 07 190 3.36E 07 198 3.50E 07 208 3.43E 07 0.10 3.22 220 3.27E 07 228 3.11E 07 240 3.06E 07 248 3.04E 07 0.11 3.04 EW0408 85JC 258 3.07E 07 270 3.39E 07 278 3.70E 07 288 3.63E 07 0.08 3.54 300 3.60E 07 308 3.30E 07 320 2.92E 07 328 2.96E 07 338 2.82E 07 350 2.70E 07 359 3.21E 07 0.07 4.02 368 3.19E 07 380 2.99E 07 388 2.64E 07 398 2.62E 07 410 2.43E 07 420 2.23E 07 428 1.97E 07 438 1.81E 07 450 1.82E 07 460 1.51E 07 470 1.46E 07 480 1.62E 07 490 1.72E 07 550 1.58E 07 558 1.49E 07 563 1.46E 07 570 1.15E 07 573 1.12E 07 580 9.16E 08 583 8.73E 08

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74 Sample Mass Susc. (m3/kg) Mr/Ms Hcr/Hc 590 8.44E 08 593 8.31E 08 600 7.67E 08 EW0408 85JC 603 7.31E 08 608 7.32E 08 613 7.86E 08 620 8.63E 08 0.20 3.32 623 8.82E 08 628 8.95E 08 633 9.65E 08 640 1.08E 07 643 1.10E 07 650 8.49E 08 0.15 4.72 653 8.77E 08 658 1.07E 07 663 1.32E 07 0.09 5.14 669 1.53E 07 677 1.72E 07 0.07 4.70 683 3.18E 07 688 4.76E 07 0.06 4.66 693 5.81E 07 698 6.56E 07 0.07 4.22 723 4.84E 07 733 4.75E 07 743 4.55E 07 753 4.14E 07 763 4.87E 07 773 4.55E 07 783 4.47E 07 793 4.18E 07 803 4.07E 07 0.08 3.68 843 4.14E 07 863 4.50E 07 883 4.09E 07 903 4.21E 07 923 3.81E 07 943 3.70E 07 963 4.01E 07 983 3.60E 07 1003 3.98E 07 1023 4.78E 07 1043 4.93E 07 1063 5.09E 07 1083 4.44E 07 1103 4.32E 07

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75 APPENDIX D M INERALOGY

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76 Table D 1. Mineralogy, Chugach and Yakutat Terranes. Fspar/Qtz 0.8 1.0 0.9 0.9 0.9 1.0 1.0 0.8 0.6 0.4 0.6 0.6 0.7 0.2 0.2 0.3 0.9 1.6 2.1 1.6 1.4 1.1 1.0 1.2 Other 2.7 0.6 Amphibole 0.0 0.0 0.0 0.0 0.0 2.3 1.9 1.2 0.0 1.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 3.9 3.9 0.0 0.9 5.5 6.6 0.8 6.1 Biotite 3.1 4.0 0.7 2.1 1.7 2.2 27.3 8.5 Clinochlore 9.6 18.9 17.5 14.3 16.7 7.2 11.7 15.1 13.6 15.0 14.7 10.9 12.7 9.7 14.5 2.2 15.0 13.1 0.0 13.1 13.7 20.4 13.7 13.1 13.3 17.9 Kaolinite 56.8 9.8 1.3 3.7 1.4 Muscovite 15.1 21.4 9.2 11.5 15.4 7.3 15.0 10.0 14.9 14.7 12.5 20.3 12.1 11.3 67.5 44.3 32.2 35.2 33.8 26.5 25.1 16.3 24.5 21.0 21.1 12.9 Feldspar 34.3 29.2 34.6 34.8 31.5 39.9 36.0 30.5 26.8 19.4 27.3 26.4 30.6 5.6 3.1 8.9 59.8 23.8 37.9 35.5 37.6 31.9 29.7 30.9 32.9 34.9 Quartz 40. 9 30.4 38.6 39.4 36.5 40.0 35.4 39.2 44.0 44.7 43.8 41.8 44.5 24.1 19.8 32.4 28.6 25.2 27.9 23.0 17.2 23.6 22.0 26.6 27.0 31.9 28.1 Sample CHU 01 CHU 03 CHU 05 CHU 10 CHU 11 CHU 16 CHU 19 CHU 20 CHU 21 CHU 22 CHU 24 CHU 25 CHU 31 KTL 01 KTM 01 KTM 02 KTU 02 KTU 03 PCL 01 PCM 02 PCM 03 PCU 03 YKL 02 YKM 01 YKM 02 YKM 03 YKU 02 Chugach Terrane Yakutat Terrane

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77 Table D 2. Mineralogy, Surveyor Fan. Fspar/Qtz 1.1 1.1 1.3 1.4 1.3 1.3 1.4 1.3 1.0 1.5 1.4 1.0 1.6 1.3 1.7 1.4 0.9 0.9 1.2 0.9 Other 0.6 0.7 Amphibole 0.0 0.0 0.0 0.2 2.9 2.6 4.3 0.8 5.9 7.3 3.1 0.2 6.0 6.8 0.0 0.0 0.0 0.0 0.2 0.0 0.0 Biotite 1.1 2.4 Clinochlore 19.4 22.5 9.4 18.3 18.7 11.1 0.0 16.3 12.4 10.8 17.9 18.3 7.5 7.8 7.3 17.4 12.8 12.1 10.4 20.3 11.1 Kaolinite 4.8 6.9 3.0 12.2 Muscovite 21.9 28.0 62.0 35.0 40.1 19.1 0.0 41.1 26.9 8.2 41.0 42.4 25.4 23.4 16.0 41.0 31.9 9.3 12.7 28.3 11.9 Feldspar 28.8 25.0 13.5 26.5 22.7 37.3 54.3 24.6 31.0 36.0 22.1 22.6 26.6 36.4 43.6 26.0 25.1 37.4 35.8 28.2 36.0 Quartz 25.1 23.4 15.1 20.0 15.7 29.4 41.4 17.2 23.9 35.2 15.1 16.4 27.5 22.6 33.1 15.6 17.9 41.2 40.8 23.2 41.0 Sample SF 05 SF 08 SF 09 SF 10 SF 14 SF 16 SF 18 SF 19 SF 20 SF 21 SF 22 SF 23 SF 26 SF 29 SF 33 SF 38 SF 42 SF 46 SF 49 SF 52 SF 54 Upper Fan Sequence (UFS) Middle Fan Sequence (MFS) Lower Fan Sequence (LFS)

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78 Table D 3. Mineralogy, EW0408 85JC. Fspar/Qtz 2.1 1.7 1.8 1.7 1.8 1.6 1.9 1.6 1.6 2.1 2.1 1.1 1.2 1.2 1.6 1.8 Other 14.0 17.2 12.6 14.0 13.9 17.6 15.8 20.0 19.6 15.4 17.7 16.2 14.8 16.2 15.9 18.4 Amphibole 5.2 7.3 5.4 5.6 5.5 5.6 5.1 5.1 4.2 4.2 4.0 3.5 3.4 3.8 4.2 4.6 Biotite 1.0 3.3 2.3 1.6 3.4 1.6 2.3 2.2 2.0 3.8 3.4 1.6 2.3 1.8 1.4 1.4 Clinochlore 18.4 8.3 11.7 14.5 8.5 10.1 8.4 7.5 7.3 8.9 7.3 5.1 7.2 9.3 7.1 8.5 Kaolinite 2.8 4.0 3.8 3.4 5.6 4.4 5.5 5.7 4.8 5.9 6.8 4.9 4.5 3.9 6.7 5.4 Muscovite 16.7 20.6 23.5 21.5 22.4 23.0 22.4 17.3 17.7 21.6 23.4 15.4 17.8 20.2 21.3 18.1 Feldspar 28.4 24.7 25.9 24.8 26.1 23.5 26.2 25.8 27.3 27.3 25.1 28.0 26.7 24.3 26.4 27.9 Quartz 13.5 14.7 14.8 14.7 14.6 14.3 14.1 16.5 17.1 12.9 12.2 25.3 23.2 20.5 17.0 15.8 Sample 1 89 170 198 359 498 608 623 643 653 673 683 723 843 983 1103 EW0408 85JC

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79 APPENDIX E MAJOR OXIDES (WT. %) Table E 1. Major oxide concentration, Chugach and Yakutat Terranes. Sample MgO P2O5 CaO TiO2 MnO Al2O3 K2O FeO Fe2O3 Chugach Terrane CHU 01m 1.77 0.32 2.57 0.88 0.09 13.97 1.65 3.15 0.62 CHU 02m 2.21 0.30 1.63 0.91 0.09 13.18 1.73 4.04 0.79 CHU 05m 2.07 0.27 2.60 1.04 0.11 13.78 1.59 3.94 0.77 CHU 11m 2.58 0.24 1.55 0.94 0.09 14.41 2.14 4.62 0.91 CHU 14m 1.84 0.25 3.10 0.64 0.06 12.15 1.45 2.62 0.51 CHU 15m 2.37 0.28 1.65 0.86 0.08 13.04 1.80 4.09 0.80 CHU 17m 2.11 0.34 3.48 0.76 0.09 13.57 1.68 3.46 0.68 CHU 18m 2.37 0.34 1.00 0.89 0.10 14.32 1.92 4.78 0.94 CHU 19m 2.57 0.28 2.46 0.74 0.12 13.69 2.11 4.51 0.88 CHU 20m 3.00 0.19 3.10 0.76 0.13 12.29 1.53 5.53 1.08 CHU 21m 1.81 0.37 2.24 0.99 0.09 11.87 1.56 3.37 0.66 CHU 22m 1.93 0.37 2.73 0.89 0.10 12.28 1.73 3.70 0.73 CHU 23m 1.63 0.36 2.63 0.84 0.08 12.33 1.37 3.14 0.62 CHU 24m 1.32 0.33 2.51 0.76 0.07 10.23 1.13 2.46 0.48 CHU 29m 2.68 0.20 5.06 0.95 0.10 11.37 1.02 4.04 0.79 CHU 30m 3.03 0.21 5.10 0.94 0.11 12.43 1.05 4.89 0.96 CHU 31m 2.19 0.24 2.16 0.82 0.07 12.66 1.77 3.42 0.67 Yakutat Terrane KTL 01 2.08 0.11 0.96 0.93 0.02 22.36 2.06 4.81 0.94 KTL 02 1.63 0.03 0.43 0.97 0.03 22.49 1.56 4.47 0.88 KTM 01 2.51 0.11 0.92 0.95 0.02 22.74 3.03 3.18 0.62 KTM 02 2.30 0.05 0.81 0.95 0.03 20.18 1.98 3.55 0.70 KTU 02 1.35 0.02 0.53 0.96 0.01 21.90 5.02 1.85 0.36 KTU 03 2.29 0.06 0.60 0.98 0.03 19.51 2.46 3.68 0.72 PCL 02 2.62 0.16 1.27 0.88 0.04 17.64 2.16 5.34 1.05 PCM 02 3.42 0.36 4.15 1.02 0.08 15.48 1.98 5.66 1.11 PCM 03 3.28 0.20 3.71 1.05 0.07 16.61 1.88 5.24 1.03 PCU 02 2.45 0.22 2.70 0.73 0.06 14.14 2.31 4.09 0.80 PCU 03 2.87 0.23 2.21 0.90 0.05 16.84 2.38 5.77 1.13 YKL 01 2.36 0.20 3.48 0.73 0.08 13.46 1.83 3.83 0.75 YKL 02 4.13 0.21 2.57 0.91 0.12 15.85 2.16 6.93 1.36 YKM 01 3.58 0.15 3.54 0.86 0.10 13.85 1.38 6.08 1.19 YKM 02 3.02 0.14 3.13 0.77 0.10 12.36 1.18 5.16 1.01 YKU 01 3.92 0.18 3.63 0.98 0.11 14.23 1.26 5.94 1.17 YKU 02 3.07 0.18 3.73 0.92 0.09 13.62 1.06 4.94 0.97

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80 Table E 2. Major oxide concentration, Surveyor Fan. Sample MgO P2O5 CaO TiO2 MnO Al2O3 K2O FeO Fe2O3 UFS SF 01 3.93 0.22 3.02 0.96 0.12 18.23 2.54 6.74 1.32 SF 02 3.93 0.21 2.99 0.93 0.13 17.87 2.37 6.74 1.32 SF 03 3.83 0.21 2.63 0.91 0.13 17.39 2.35 6.65 1.30 SF 04 3.52 0.20 2.39 0.84 0.12 16.76 2.33 6.44 1.26 SF 05 3.87 0.24 2.94 0.94 0.15 18.75 2.62 6.78 1.33 SF 06 3.63 0.24 3.22 0.87 0.15 17.33 2.36 6.16 1.21 SF 07 3.23 0.26 2.16 0.86 0.10 12.24 1.91 4.55 0.89 SF 08 3.91 0.23 1.92 0.90 0.15 16.16 2.53 6.22 1.22 SF 09 3.76 0.19 1.73 0.84 0.13 17.10 2.58 6.34 1.24 SF 10 3.89 0.18 2.05 0.86 0.11 16.60 2.47 6.23 1.22 MFS SF 12 3.77 0.21 2.04 0.89 0.11 16.90 2.52 6.45 1.26 SF 14 4. 26 0.17 2.70 0.80 0.12 13.87 1.99 5.96 1.17 SF 15 2.57 0.24 3.31 0.73 0.08 14.00 1.63 4.31 0.84 SF 16 3.30 0.28 6.03 0.86 0.16 15.21 1.86 5.20 1.02 SF 17 4.26 0.25 4.03 0.86 0.19 13.20 2.31 6.45 1.26 SF 18 2.68 0.25 5.97 0.82 0.11 12.96 1.23 3.95 0.77 SF 19 4.97 0.23 2.04 0.85 0.14 15.84 2.43 6.76 1.33 SF 20 3.92 0.23 3.07 0.97 0.15 18.22 2.35 6.19 1.21 SF 21 3.99 0.22 5.24 1.01 0.15 15.65 1.47 5.37 1.05 SF 22 4.58 0.18 1.90 0.85 0.17 16.01 2.33 6.49 1.27 SF 23 3.72 0.15 1.36 0.76 0.39 13.10 2.23 6.46 1.27 SF 24 3.42 0.18 2.74 0.97 0.15 14.62 2.04 6.71 1.32 SF 26 2.96 0.20 3.63 0.98 0.16 14.80 1.72 6.05 1.19 SF 28 3.16 0.18 2.62 0.83 0.09 13.65 1.80 5.11 1.00 SF 29 3.28 0.22 3.34 0.90 0.12 14.34 1.77 5.34 1.05 SF 31 3.28 0.25 3.66 0.94 0.11 14.53 1.73 5.46 1.07 LFS SF 33 2.55 0.22 3.68 0.89 0.10 13.65 1.56 4.23 0.83 SF 35 3. 07 0.21 2.57 0.88 0.11 14.88 1.87 5.28 1.03 SF 38 2.88 0.11 1.06 0.64 0.07 12.19 1.83 5.03 0.99 SF 40 1.43 0.19 2.42 0.67 0.05 12.00 1.33 2.36 0.46

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81 APPENDIX F TRACE ELEMENTS (PPM)

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82 Table F 1. Trace element c oncentration, Chugach Terrane. U 2.99 2.36 2.85 3.03 1.97 2.63 2.80 2.69 3.19 2.08 4.06 2.34 3.36 2.87 1.90 1.51 3.57 Th 8.67 6.81 9.59 8.98 5.64 7.68 9.44 7.73 8.65 6.67 10.49 7.79 9.42 7.99 3.95 3.97 9.93 Pb 16.77 13.90 23.18 44.73 10.57 15.22 12.13 17.05 33.70 33.31 31.13 13.66 16.72 14.62 6.98 7.93 16.04 Hf 1.43 2.37 1.22 1.10 1.51 2.13 1.93 2.66 1.81 0.98 1.78 1.45 1.32 1.17 2.34 1.99 2.11 Ba 871.88 846.54 811.81 1144.15 729.72 938.33 811.35 871.41 1053.19 822.76 798.44 753.03 720.77 593.29 554.32 569.80 929.16 Nb 13.08 12.73 14.07 14.10 9.43 12.37 11.93 12.43 13.54 10.78 14.84 11.83 13.15 11.55 10.25 9.08 10.86 Zr 46.42 85.60 39.42 35.34 47.94 72.03 59.50 92.84 59.94 29.92 55.25 48.88 40.89 35.82 80.93 68.30 70.26 Y 27.37 24.08 32.75 24.99 22.08 27.26 27.80 24.37 26.04 23.64 33.01 30.09 30.76 27.44 21.88 22.48 26.30 Sr 341.04 306.31 294.85 286.52 311.04 271.28 316.31 186.24 267.16 244.69 324.13 260.04 369.22 329.56 346.16 290.10 309.82 Rb 49.94 60.66 54.93 77.21 45.42 61.75 53.28 66.59 81.12 53.80 54.84 55.61 45.76 37.64 31.13 32.12 53.44 Ga 14.92 15.92 16.50 18.60 14.06 16.18 15.66 16.98 19.35 16.90 16.27 14.68 15.68 12.87 13.89 14.41 15.50 Zn 78.40 95.49 97.65 118.08 65.63 84.73 81.70 112.66 126.87 122.28 102.84 93.81 83.71 73.71 68.83 89.11 82.93 Cu 42.36 69.05 54.07 91.09 28.89 41.81 35.08 56.60 67.13 203.94 92.84 73.07 67.65 60.03 38.91 55.80 77.90 Co 12.22 16.90 16.69 16.15 9.54 10.87 11.18 18.57 17.62 30.30 20.03 20.76 13.96 11.51 15.92 18.69 12.98 Cr 62.29 103.25 82.43 100.55 63.24 107.28 73.19 109.18 99.63 115.53 83.01 74.19 67.74 55.13 107.34 125.91 90.94 V 105.64 139.36 137.41 149.38 99.87 141.04 115.82 145.46 152.12 147.54 127.60 123.57 117.86 99.00 153.59 179.99 119.35 Sc 13.86 15.48 18.35 16.28 12.80 16.60 14.80 15.50 16.98 18.21 18.59 16.94 17.74 14.97 18.49 22.67 16.93 Li 27.36 41.61 37.36 45.73 24.94 42.47 30.16 55.08 49.28 29.84 32.86 33.23 28.62 23.12 23.44 27.08 33.56 Sample CHU 01m CHU 02m CHU 05m CHU 11m CHU 14m CHU 15m CHU 17m CHU 18m CHU 19m CHU 20m CHU 21m CHU 22m CHU 23m CHU 24m CHU 29m CHU 30m CHU 31m Chugach Terrane

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83 Table F 2. Trace element c oncentration, Yakutat Terrane U 2.77 3.17 3.12 3.10 3.18 2.78 2.32 3.05 2.29 2.09 4.94 2.26 2.02 1.45 1.37 1.53 1.43 Th 9.39 9.70 6.68 6.46 7.67 6.27 6.45 5.63 5.23 5.07 6.16 5.17 5.53 4.43 3.98 4.82 4.72 Pb 20.39 20.20 12.84 14.90 14.96 19.94 12.74 10.69 9.51 11.47 12.97 10.18 14.46 9.60 8.50 8.45 8.58 Hf 2.23 2.69 2.17 1.78 2.74 2.61 2.14 3.32 3.00 1.29 1.88 1.48 1.31 1.38 1.21 1.35 1.25 Ba 546.05 488.76 1523.15 960.03 1537.83 1356.72 696.83 633.27 622.11 1002.39 890.98 919.41 877.04 565.08 502.13 556.79 494.10 Nb 13.05 14.30 10.29 10.82 12.88 12.49 11.25 14.90 13.41 9.92 11.52 9.83 10.71 8.11 7.74 9.03 8.80 Zr 71.68 91.38 71.43 55.08 97.48 126.43 72.59 125.72 115.90 42.27 61.36 46.12 43.79 45.87 39.92 43.50 39.62 Y 20.62 26.87 16.39 19.52 14.00 24.42 20.44 25.31 20.95 20.71 22.92 20.65 23.81 22.51 21.20 22.68 23.71 Sr 145.85 111.79 145.31 145.32 46.96 205.78 217.55 450.01 431.12 410.67 294.74 428.31 292.42 264.52 238.55 285.85 310.39 Rb 82.21 81.49 99.34 64.10 146.74 80.94 74.32 48.01 41.44 56.12 82.11 48.20 73.62 49.03 47.22 41.10 32.06 Ga 23.79 34.35 31.87 24.54 31.86 28.04 22.81 21.40 20.54 17.69 23.77 16.88 22.57 18.82 16.92 18.70 16.49 Zn 119.97 142.88 119.59 139.29 53.40 131.98 122.28 108.20 103.77 87.32 109.35 76.24 127.19 99.15 84.81 93.30 78.07 Cu 50.25 59.96 60.74 62.44 33.51 95.39 43.87 23.60 29.63 20.83 40.53 17.67 70.80 56.75 56.06 69.06 59.89 Co 26.57 15.99 13.01 19.50 4.15 12.27 18.13 14.06 16.23 12.05 12.05 11.35 23.95 21.72 18.20 23.49 19.95 Cr 74.24 82.82 91.18 83.49 83.50 90.82 93.89 64.01 71.08 69.54 91.63 70.26 112.68 118.08 108.39 124.71 112.65 V 159.13 183.95 177.02 156.44 149.73 243.48 173.61 125.69 145.00 129.68 168.28 120.55 204.98 189.43 175.61 187.88 170.89 Sc 19.00 22.85 20.23 19.10 18.36 23.81 18.72 17.26 18.27 15.63 19.34 14.93 23.45 22.13 21.05 22.68 21.45 Li 59.01 62.53 44.28 54.94 13.63 45.00 73.52 54.70 57.98 41.52 42.64 28.48 48.31 32.61 31.11 30.70 23.81 Sample KTL 01 KTL 02 KTM 01 KTM 02 KTU 02 KTU 03 PCL 02 PCM 02 PCM 03 PCU 02 PCU 03 YKL 01 YKL 02 YKM 01 YKM 02 YKU 01 YKU 02 Yakutat Terrane

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84 Table F 3. Trace element c oncentration, Surveyor Fan. U 2.07 2.02 2.41 2.39 2.16 2.09 2.05 2.21 2.19 1.78 2.11 1.37 1.50 2.25 2.01 2.13 1.68 2.22 1.72 2.14 1.75 1.56 1.43 1.75 1.93 2.04 2.24 2.09 1.83 2.00 Th 5.68 5.46 5.72 5.86 6.15 6.10 5.74 6.31 6.54 5.45 6.04 4.36 4.10 4.39 4.84 4.49 5.14 5.55 4.59 6.19 5.53 4.31 3.70 5.12 4.64 5.89 6.99 6.35 4.51 6.00 Pb 16.29 13.27 13.93 22.70 17.14 17.81 17.57 17.39 24.37 17.94 18.94 13.22 9.72 17.08 14.79 9.74 16.16 17.25 10.61 36.26 32.74 42.23 17.83 20.77 12.14 15.45 12.84 19.27 14.74 8.91 Hf 2.09 1.99 2.11 2.21 2.27 2.14 2.15 2.30 2.39 2.28 2.33 1.95 1.80 1.91 2.41 1.63 2.37 1.89 1.44 2.40 2.41 2.89 3.10 2.02 2.04 1.94 2.27 2.06 1.94 1.75 Ba 869.01 810.71 887.55 1013.39 924.08 888.35 773.79 999.30 1099.03 1449.91 978.65 2083.92 812.08 843.61 911.03 668.48 1164.60 1176.15 791.91 2621.62 2194.37 3180.38 2429.62 1075.73 954.60 1045.69 1053.48 1112.66 933.80 854.96 Nb 10.86 10.29 10.58 10.63 10.97 10.74 10.66 11.01 11.42 9.55 11.12 8.77 9.82 10.22 11.12 9.16 10.23 10.11 8.71 10.23 9.78 7.68 6.44 10.56 10.74 11.61 11.16 10.59 7.25 8.66 Zr 72.11 68.01 75.20 80.79 81.09 76.67 73.76 80.18 85.61 81.82 83.55 74.06 63.05 66.97 87.18 53.72 87.62 65.32 45.39 91.10 95.64 105.67 110.41 68.94 69.06 65.07 77.24 71.89 70.43 55.51 Y 23.02 23.48 23.43 24.17 23.58 23.62 19.95 22.81 24.31 22.48 23.96 20.14 22.28 23.06 21.32 24.33 24.81 23.81 24.62 27.18 24.76 27.26 31.34 20.54 22.56 22.80 25.47 25.62 17.83 20.79 Sr 243.56 250.21 244.78 259.98 255.51 268.82 220.93 232.72 237.36 245.31 251.65 246.60 381.24 395.53 239.04 364.44 250.71 315.33 313.72 224.63 202.53 252.07 306.51 296.22 321.60 336.89 355.25 286.87 160.59 326.64 Rb 80.37 73.46 75.84 82.61 82.12 75.87 47.23 75.97 95.05 84.71 84.62 79.55 52.09 50.56 38.11 35.52 91.05 72.99 44.14 93.45 68.56 59.01 52.92 63.50 47.75 57.27 55.42 67.88 67.00 40.11 Ga 22.02 21.26 21.31 22.36 21.73 20.68 16.39 21.76 23.35 22.23 21.71 20.53 15.76 16.37 20.30 14.95 20.90 20.77 17.20 24.93 22.18 22.82 22.47 17.04 16.34 17.63 18.35 18.88 16.27 11.77 Zn 252.06 129.03 116.28 139.18 118.51 111.96 91.87 119.99 138.71 131.45 122.50 125.39 80.13 98.43 134.22 72.63 132.19 140.81 93.01 152.22 147.01 135.52 120.81 107.00 98.60 109.94 95.31 104.92 112.73 52.29 Cu 60.63 84.71 53.07 89.08 53.46 48.31 39.62 58.55 85.57 135.17 60.23 70.23 21.09 50.64 56.39 33.49 43.10 68.79 57.99 137.59 187.78 119.97 67.87 66.04 51.82 38.85 41.23 61.16 82.91 23.13 Co 20.22 23.33 22.79 35.45 21.16 20.71 25.59 22.50 23.38 27.96 23.95 21.67 13.13 26.39 21.38 18.80 30.05 23.95 76.68 36.05 40.27 22.14 19.85 15.23 17.88 18.65 16.86 17.72 16.41 8.63 Cr 115.89 123.05 119.14 121.05 118.50 113.40 96.15 118.78 125.72 104.69 111.08 102.34 73.35 80.14 101.03 79.31 96.78 96.38 101.38 112.35 97.96 69.20 51.30 93.90 92.59 92.00 93.68 92.49 62.54 60.23 V 201.31 197.11 198.40 209.15 193.48 184.18 144.39 185.90 198.18 191.24 189.91 167.65 135.08 147.63 192.71 143.08 178.47 177.75 168.21 196.01 187.86 158.91 153.85 155.22 150.27 154.64 145.69 156.50 123.09 80.55 Sc 22.28 22.34 22.59 22.58 21.25 20.95 12.88 19.66 22.11 21.22 21.09 20.79 16.23 17.18 16.84 18.54 19.93 20.01 22.13 23.88 17.80 21.13 22.65 17.39 17.82 18.39 18.05 18.02 15.40 11.10 Li 56.87 51.69 54.37 55.92 56.12 52.40 40.29 57.15 62.71 54.84 59.89 48.14 24.52 27.90 45.01 21.50 55.12 49.31 31.07 62.53 62.18 46.27 37.40 41.62 36.90 40.87 39.40 46.80 43.73 24.08 Sample SF 01 SF 02 SF 03 SF 04 SF 05 SF 06 SF 07 SF 08 SF 09 SF 10 SF 12 SF 14 SF 15 SF 16 SF 17 SF 18 SF 19 SF 20 SF 21 SF 22 SF 23 SF 24 SF 26 SF 28 SF 29 SF 31 SF 33 SF 35 SF 38 SF 40 Upper Fan Sequence (UFS) Middle Fan Sequence (MFS) Lower Fan Sequence (LFS)

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85 APPENDIX G REE ABUNDANCE (PPM)

PAGE 86

86 Table G 1. Rare Earth Element c oncentration Chugach Terrane Lu 0.30 0.31 0.33 0.29 0.29 0.34 0.36 0.34 0.34 0.27 0.35 0.29 0.33 0.30 0.29 0.30 0.32 Yb 2.23 2.18 2.62 2.12 2.00 2.36 2.50 2.26 2.39 2.01 2.67 2.31 2.48 2.25 2.00 2.09 2.27 Tm 0.37 0.35 0.45 0.35 0.32 0.38 0.40 0.36 0.38 0.33 0.46 0.40 0.42 0.38 0.32 0.33 0.37 Er 2.63 2.37 3.26 2.48 2.19 2.65 2.74 2.44 2.57 2.32 3.22 2.89 3.01 2.69 2.18 2.26 2.59 Ho 0.96 0.85 1.17 0.88 0.77 0.94 0.97 0.87 0.91 0.83 1.16 1.05 1.08 0.97 0.77 0.79 0.92 Dy 4.93 4.34 5.96 4.46 3.91 4.86 5.04 4.56 4.62 4.11 5.98 5.40 5.58 4.96 3.89 3.96 4.65 Tb 0.89 0.80 1.06 0.80 0.70 0.87 0.93 0.87 0.83 0.73 1.06 0.96 1.00 0.89 0.69 0.68 0.82 Gd 5.84 5.25 6.70 5.12 4.44 5.57 6.05 5.92 5.26 4.53 6.90 6.16 6.38 5.77 4.24 4.28 5.19 Eu 1.59 1.47 1.76 1.42 1.16 1.46 1.35 1.62 1.27 1.24 1.83 1.63 1.75 1.56 1.24 1.23 1.46 Sm 6.50 5.89 7.18 5.64 4.84 6.17 6.82 6.84 5.79 4.75 7.62 6.56 6.99 6.32 4.43 4.30 5.75 Nd 30.41 27.91 32.71 26.03 21.74 28.67 31.43 32.10 26.47 21.72 36.25 29.76 32.28 29.00 19.86 18.23 26.69 Pr 8.09 7.24 8.59 6.84 5.66 7.52 8.23 8.38 6.87 5.70 9.58 7.74 8.39 7.60 5.13 4.55 7.08 Ce 69.35 61.84 74.05 59.73 47.66 64.44 69.17 71.54 57.87 48.68 82.66 63.49 70.92 64.58 42.29 37.01 59.75 La 34.35 30.73 35.67 29.22 23.23 31.68 33.10 34.47 27.83 24.23 41.01 31.08 34.66 32.16 20.37 17.59 29.68 Sample CHU 01 CHU 02 CHU 05 CHU 11 CHU 14 CHU 15 CHU 17 CHU 18 CHU 19 CHU 20 CHU 21 CHU 22 CHU 23 CHU 24 CHU 29 CHU 30 CHU 31 Chugach Terrane

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87 Table G 2. R are Earth Element c oncentration, Yakutat Terrane Lu 0.31 0.39 0.27 0.29 0.23 0.38 0.31 0.28 0.36 0.30 0.28 0.32 0.28 0.32 0.30 0.28 0.29 0.29 Yb 2.12 2.60 1.86 1.93 1.55 2.54 2.10 1.88 2.40 2.01 1.89 2.16 1.89 2.22 2.10 1.95 2.04 2.08 Tm 0.32 0.42 0.27 0.30 0.23 0.39 0.32 0.30 0.38 0.32 0.30 0.34 0.30 0.36 0.34 0.32 0.33 0.34 Er 2.14 2.73 1.79 1.97 1.50 2.54 2.11 1.96 2.48 2.16 2.04 2.28 2.05 2.41 2.26 2.16 2.26 2.36 Ho 0.76 0.95 0.62 0.67 0.49 0.86 0.72 0.69 0.88 0.75 0.71 0.80 0.70 0.84 0.79 0.75 0.81 0.84 Dy 3.91 4.80 2.96 3.27 2.26 4.09 3.55 3.48 4.37 3.79 3.57 3.97 3.60 4.11 3.89 3.74 3.97 4.26 Tb 0.72 0.86 0.54 0.58 0.37 0.69 0.63 0.62 0.76 0.67 0.63 0.70 0.63 0.70 0.66 0.64 0.69 0.74 Gd 4.87 5.56 3.73 3.88 2.37 4.36 4.13 4.04 4.89 4.29 4.08 4.52 4.08 4.23 4.00 3.83 4.24 4.49 Eu 1.36 1.61 1.24 1.15 0.62 1.34 1.22 1.13 1.43 1.30 1.23 1.24 1.22 1.23 1.17 1.08 1.20 1.27 Sm 5.47 6.48 4.37 4.59 2.88 4.97 4.80 4.41 5.08 4.44 4.41 4.79 4.40 4.38 3.97 3.79 4.37 4.56 Nd 26.07 30.24 20.10 21.47 18.04 22.05 22.99 21.69 23.23 19.90 20.00 21.01 20.49 18.85 17.29 15.92 18.47 19.89 Pr 6.84 7.95 5.18 5.47 5.03 5.63 6.02 5.65 6.02 5.14 5.14 5.34 5.38 4.79 4.39 4.01 4.64 5.05 Ce 57.21 68.66 43.86 45.98 43.11 47.20 51.00 48.01 52.48 43.08 43.50 44.77 45.68 39.64 35.63 31.36 38.15 41.42 La 28.02 32.71 21.41 22.08 23.06 22.40 24.95 22.79 26.03 20.73 21.31 21.16 22.97 19.16 17.88 16.11 18.15 19.98 Sample KTL 01 KTL 02 KTM 01 KTM 02 KTU 02 KTU 03 Mean PCL 02 PCM 02 PCM 03 PCU 02 PCU 03 YKL 01 YKL 02 YKM 01 YKM 02 YKU 01 YKU 02 Yakutat Terrane

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88 Table G 3. Rare Earth Element concentration, Surveyor Fan. Sample La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu UFS SF 01 19.89 41.63 5.02 19.63 4.45 1.21 4.32 0.70 4.04 0.82 2.32 0.35 2.23 0.32 SF 02 19.20 40.83 4.93 19.35 4.37 1.19 4.30 0.70 4.12 0.83 2.37 0.35 2.21 0.33 SF 03 19.25 41.22 4.97 19.34 4.37 1.19 4.33 0.68 4.03 0.82 2.36 0.35 2.25 0.33 SF 04 20.44 42.82 5.18 20.06 4.63 1.23 4.39 0.72 4.25 0.86 2.46 0.37 2.30 0.34 SF 05 20.72 42.60 5.09 19.85 4.39 1.20 4.28 0.68 4.02 0.80 2.32 0.34 2.18 0.32 SF 06 20.97 43.69 5.21 20.07 4.49 1.20 4.42 0.70 4.06 0.81 2.31 0.35 2.18 0.31 SF 07 18.03 43.17 4.67 18.30 4.07 1.08 3.96 0.64 3.65 0.71 2.09 0.30 1.92 0.28 SF 08 19.16 42.42 4.97 19.57 4.38 1.18 4.34 0.69 4.09 0.82 2.38 0.35 2.22 0.33 SF 09 20.63 43.53 5.16 20.06 4.45 1.22 4.36 0.70 4.12 0.83 2.38 0.36 2.25 0.34 SF 10 18.62 39.09 4.79 18.71 4.31 1.27 4.25 0.68 3.94 0.79 2.26 0.33 2.15 0.32 MFS SF 12 19.77 41.82 5.01 19.45 4.40 1.20 4.26 0.69 4.09 0.81 2.31 0.35 2.25 0.33 SF 14 15.75 33.65 4.06 16.09 3.72 1.17 3.81 0.61 3.56 0.71 2.03 0.31 1.96 0.29 SF 15 18.66 39.22 4.81 19.09 4.33 1.25 4.20 0.67 3.94 0.76 2.16 0.32 2.05 0.29 SF 16 18.79 39.08 4.79 18.78 4.28 1.24 4.33 0.69 3.98 0.79 2.26 0.32 2.09 0.30 SF 17 13.13 34.64 3.61 14.80 3.67 1.04 3.70 0.61 3.60 0.74 2.16 0.33 2.15 0.33 SF 18 19.19 40.73 4.87 19.63 4.60 1.26 4.48 0.72 4.21 0.85 2.36 0.35 2.18 0.31 SF 19 18.66 41.70 4.99 20.15 4.68 1.31 4.67 0.76 4.46 0.89 2.53 0.38 2.43 0.36 SF 20 19.13 40.24 4.88 19.29 4.43 1.26 4.34 0.68 4.11 0.82 2.40 0.36 2.31 0.34 SF 21 18.62 38.65 4.74 18.82 4.47 1.25 4.39 0.71 4.31 0.86 2.44 0.36 2.26 0.33 SF 22 21.76 46.76 5.76 22.89 5.35 1.57 5.41 0.86 5.06 0.98 2.81 0.43 2.59 0.39 SF 23 17.86 38.53 4.74 19.12 4.52 1.34 4.61 0.76 4.49 0.90 2.59 0.39 2.58 0.39 SF 24 18.55 38.45 5.29 21.78 5.38 1.66 5.47 0.88 5.17 1.01 2.83 0.43 2.73 0.40 SF 26 17.78 36.65 5.34 22.77 5.81 1.81 6.02 0.99 5.83 1.14 3.28 0.49 3.08 0.46 SF 28 17.78 36.86 4.48 17.74 4.04 1.14 3.95 0.62 3.55 0.71 2.01 0.30 1.89 0.28 SF 29 18.12 37.50 4.56 18.21 4.30 1.20 4.16 0.67 3.92 0.79 2.25 0.33 2.13 0.31 SF 31 20.45 43.10 5.23 20.72 4.62 1.26 4.45 0.70 4.08 0.79 2.24 0.33 2.12 0.32 LFS SF 33 25.83 52.51 6.32 24.41 5.19 1.35 4.92 0.78 4.55 0.88 2.48 0.37 2.34 0.34 SF 35 21.89 46.44 5.59 21.77 4.89 1.30 4.79 0.76 4.51 0.89 2.53 0.38 2.37 0.35 SF 38 15.73 34.49 4.18 16.52 3.75 1.03 3.71 0.60 3.43 0.67 1.92 0.29 1.83 0.27 SF 40 23.28 46.99 5.56 21.16 4.48 1.15 4.23 0.64 3.70 0.71 2.02 0.29 1.86 0.27

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89 LIST OF REFERENCES Addison, J. A., 2009, High resolution paleoceanography of the Gulf of Alaska, subarctic northeast Pacific Ocean, since the last glacial maximum: Insights into a dynamic atmosphere ocean ecosystem linkage at decadal to millennial timescales [Ph.D. Thesis]: Fairbanks, University of Alaska, 248 p. Anderson, S.P., 2005, Glaciers show direct linkage between erosion rate and chemical weathering fluxes : Geomorphology, v. 67, p. 147 157. Anderson, S.P., Drever, J.I., and Humphrey, N.F., 1997, Chemical weathering in glacial environments : Geology, v. 25, p. 399 402. Andrews, J.T., and Eberl, D.D., 2007, Quantitative mineralogy of surface sediments on the Iceland shelf, and application to down core studies of Holocene ice ra fted sediments : Journal of Sedimentary Research, v. 77, p. 469 479. Barron, J.A., Bukry, D., Dean, W.E., Addison, J.A., and Finney, B., 2009, Paleoceanography of the Gulf of Alaska during the past 15,000 years: Results from diatoms, silicoflagellates, and geochemistry : Marine Micropaleontology, v. 72, p. 176 195. Berger, A.L., Spotila, J.A., Chapman, J.B., Pavlis, T.L., Enkelmann, E., Ruppert, N.A., Buscher, J.T., 2008, Architecture, kinematics, and exhumation of a convergent orogenic wedge: A thermochron oligical investigation of tectonic climatic interactions within the central St. Elias orogen, Alaska : Earth and Planetary Science Letters, v. 270, p. 13 24. Bhatia, M.R., and Crook, K.A.W. 1986, Trace element characteristics of graywackes and tectonic set ting discrimination of sedimentary basins : Contributions in Mineral Petrology, v. 92, p. 181 193. Bischoff, J.L., and Cummins, K., 2001, Wisconsin Glaciation of the Sierra Nevada (79,000 15,000 yr B.P.) as recorded by rock flour in sediments of Owens Lake California : Quaternary Research, v. 55, p. 14 24. Bruhn, R.L., Pavlis, T.L., Plafker, G., and Serpa, L., 2004, Deformation during terrane accretion in t he Saint Elias orogen, Alaska: Geological Society of America Bulletin, vol. 116, no. 7 8, p. 771 787 Bruns, T.R., 1983, Model for the origin of the Yakutat block, an accreting terrane in the northern Gulf of Alaska: Geology, v. 11, p. 718 721.

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90 Cardona, A., Cordani, U.G., Ruiz, J., Valencia, V., Nutman, A.P., Sanchez, A.W., 2009, U Pb zircon geochronolog y and Nd isotopic signatures of the pre Mesozoic metamorphic basement of eastern Peruvian Andes: Growth and Provenance of a late Neoproterozoic to Carboniferous accretionary orogen on the northwest margin of Gondwana : Journal of Geology, v. 117, p. 285 30 5. Carlson, P.R., Bruns, T.R., and Fisher, M.A., 1990, Development of slope valleys in the glacimarine environment of a complex subduction zone, Northern Gulf of Alaska : Geological Society, London, Special Publications, v. 53, p. 139 153. Clark, D. A., 19 84, Hysteresis properties of sized dispersed monoclinic pyrrhotite grains : Geophys ical Res earch Lett ers v. 11, no. 3, p. 173 176. Cloetingh, S., Matenco, L., Bada, G., Dinu, C., and Mocanu, V., 2005, The evolution of the Carpathians Pannonian system: In teractions between neotectonics, deep structure, polyphase orogeny and sedimentary basins in a source to sink natural laboratory : Tectonophysics, v. 410, no. 1 4, p. 1 14. Coakley, J.P., and Syvitski, J.P.M., 1991. SediGraph technique. in Syvitski, J.P.M. (Ed.), Principles, Methods, and Application of Particle Size Analysis: (Cambridge Univ. Press), 129 142. Folk, R.L., 1974. Petrology of Sedimentary Rocks: Austin, Texas. Cowan, D.S., 1982, Geological evidence for post 40 m.y. B.P. large scale northwestwar d displacement of part of southeastern Alaska : Geology, v. 10, no. 6, p. 309 313. Cowan, E.A., Brachfeld, S.A., Powell, R.D., and Schoolfield, S.C., 2006, Terrane specific rock magnetic characteristics preserved in glacimarine sediment from southern coast al Alaska : Canadian Journal of Earth Sciences, v. 43, p. 1269 1282. Davis, J.C., 2002, Statistics and Data Analysis in Geology : Wiley, John and Sons Inc., 638 pp. Day, R., Fuller, M.D., and Schmidt, V.A., 1977, Hysteresis properties of titanomagnetites: grain size and composition dependence : Physics of Earth and Planetary Interiors, v. 13, p. 260 266. Dekkers, M. J., 1988, Magnetic properties of natural pyrrhotite Part I: Behaviour of initial susceptibility and saturation magnetization related rock magnetic parameters in a grain size dependent framework : Physics of Earth and Planetary Interiors, v. 52, no. 3 4, p. 376 393. Dessai, D.V.G., Nayak, G.N., and Basavaiah, N., 2009, Grain size, geochemistry, magnetic susceptibility: proxies in identi fying sources and factors controlling distribution of meta ls in a tropical estuary, India: Estuarine, Coastal and Shelf Science, v. 85 p. 1 12.

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91 Dekkers,M. J.,1989, Magnetic properties of natural pyrrhotite Part II: High and low temperature behavior of J rs and TRM as function of grain size : Physics of Earth and Planetary Interiors, v. 57, no. 3 4, p. 266 283. Diekmann, B., Kuhn, G., Rachold, V., Abelmann, A., Brathauer, U., Fuetterer, D.K., Gersonde, R., and Grobe, H., 2000, Terrigenous sediment suppl y in the Scotia Sea (Southern Ocean): response to Late Quaternary ice dynamics in Patagonia and on the Antarctic Peninsula : Paleogeography, Palaeoclimatology, Palaeoecology, v. 162, p. 357 387. Dinelli, E., Tateo, F., Summa, V., 2007, Geochemical and mine ralogical proxies for grain size in mudstones and siltstones from the Pleistocene and Holocene of the Po River alluvial plain, Italy : Geological Society of America Special Paper 420, p. 25 35. Direen, N.G., Pfeiffer, K.M., and Schmidt, P.W., 2008, Strong remanent magnetization in pyrrhotite: A structurally controlled example from the Paleoproterozoic Tanami orogenic gold province, northern Australia : Precambrian Research, v. 165, no. 1 2, p. 96 106. Dunlop, D.J., 2002, Theory and application of the Day pl ot (Mr/Ms versus Hcr/Hc) 1. Theoretical curves and tests using titanomagnetite data : Journal of Geophysical Research, v. 107, p. 1 22. Eberl, D.D., 2003, Quantitative mineralogy of the Yukon River System: Variations with Reach and Season, and sediment so urce unmixing : American Mineralogist, v. 89, no. 11 12, p 1784 1794. Enkelmann, E., Zeitler, P.K., Pavlis, T.L., Garver, J.I., and Ridgway, K.D., 2009, Intense localized rock uplift and erosion in the St. Elias orogen of Alaska : Nature Geoscience, v. 2, p. 360 363. Evans, M.E., and Heller, F., 2003, Environmental Magnetism, Volume 86: Principles and Applications of Enviromagnetics : Elsevier Science, Burlington, MA. Eyels, C.H., Eyles, N., and Lagoe, M.B., 1991, The Yakataga Formation: A six million year record of temperate glacial marine sedimentation in the Gulf of Alaska, in Anderson, J.B. and Ashley, G.M. (eds), Glacial Marine Sedimentation: Paleoclimatic Significance : Geological Soc iety of America Special Paper 261, p.159 180. Farmer, G.L., Barber, D ., and Andrews, J., 2003, Provenance of Late Quaternary ice proximal sediments in the North Atlantic: Nd, Sr and Pb isotopic evidence : Earth and Planetary Science Letters, v. 209, p. 227 243. Fedo, C.M., Sircombe, K.N., and Rainbird, R.H., 2003, Detrital zircon analysis of the sedimentary record : Reviews in mineralogy and geochemistry, v. 53, no. 1, p. 277 303.

PAGE 92

92 Gehrels, G.E. and Saleeby, J.B., 1987, Geologic framework, tectonic evolution, and displacement history of the Alexander Terrane: Tectonics, v. 6 n. 2, p. 151 173. Granath, G., 1982, Application of fuzzy clustering and fuzzy classification to evaluate the provenance of glacial till : Mathematical Geology, v. 16, no. 3, p. 283 301. Haeussler, P.J., Gehrels, G.E., Karl, S.M., 2004, Constraints on the age and Provenance of the Chugach Accretionary Complex from dtrital zircons in the Sitka Graywacke near Sitka, Alaska: U.S., Geological Survey Professional Paper 1709 F, pp. 24. Hallet B., Hunter, L., and Bogen, J., 1995, Rates of erosion and sediment evacuation by glaciers: A review of field data and their implications : Global and Planetary Change, v. 12, p. 213 235 Hemming, S.R., van de Flierdt, T., Goldstein, S.L., Franzese, A.M., Roy, M.,Gastineau, G., and Landrot, G., 2007, Strontium isotope tra cing of terrigenous sediment dispersal in the Antarctic Circumpolar Current: Implications for constraining frontal positions : Geochemistry, Geophysics, Geosystems, v. 8, no. 6, p. 1 13. Hounslow, M.W., and Maher, B.A., 1996, Quantitative extraction and an alysis of carriers of magnetization in sediments : Geophys ical J ournal Int ernationale v. 124, p. 57 74. Jaeger J. M., Nittrouer, C. A., Scott, N. D., and Milliman, J. D., 1998, Sediment accumulation along a glacially impacted mountainous coastline: north east Gulf of Alaska : Basin Research, v. 10, p. 155 173. Jaeger, J., B. Hallet, T. Pavlis, J. Sauber, D. Lawson, J. Milliman, S. Anderson, and R. Anderson, 2001, Orogenic and Glacial Research in Pristine Southern Alaska : EOS, v. 82, no. 19, p. 213 216. Jaeger, J.M., and Nittrouer, C.A., 1999, Sediment deposition in an Alaska fjord: Controls on the formation and preservation of sedimentary structures in Icy Bay : Journal of Sedimentary Research, v. 69, no. 5, p. 1011 1026. Jaeger, J.M., and Nittrouer C.A., 2006, A quantitative examination of modern sedimentary lithofacies formation on the glacially influenced Gulf of Alaska continental shelf : Continental Shelf Research, v 26 p. 2178 2204. Johnsson, M.J., and Mea, R.H., 1990, chemical weathering of fluvial sediments during alluvial storage: the Macuapanim Island point bar, Solimoes River, Brazil : J ournal of Sedimentary Research, v. 60, no. 6, p. 827 842. Kamenov, G.D., Brenner, M., and Tucker, J.L., 2009, Anthropogenic versus natural control on trac e element and Sr Nd Pb isotope stratigraphy in peat sediments of southeast Florida (USA), ~1500 AD to present : Geochemica et Cosmochimica Acta, v. 73, p. 3549 3567.

PAGE 93

93 Klein, D.G., 1984, Role of depositional depth and source terrain uplift rates on sedimenta tion patterns in back arc basins of western Pacific : AAPG Bulletin v. 68, p. 495. Koehler, C.M., Heslop, D., Dekkers, M.J., Krijgsman, W., van Hinsbergen, D.J.J., and von Dobeneck, T., 2008, Tracking provenance change during the late Miocene in the easter n Mediterranean using geochemical and environmental magnetic parameters : Geochemistry Geophysics Geosystems, v. 9, 14 pp. Kulm, L.D., von Huene, R., Duncan, J.R., Ingle, Jr., J.C., Kling, S.A., Musich, L.F., Piper, D.J.W., Pratt, R.M., Schrader, H.J., Wes er, O.E., and Wise, Jr., S.W., 1973, Site 178: Initial Reports of the DSDP: Leg 18, 1077 pp Kusky, T.M., Bradley, D.C., and Haeussler, P., 1997, Progressive deformation of the Chugach accretionary complex, Alaska, during a P aleogene ridge trench encounter: Journal of Structural Geology, v. 19, n. 2, p. 139 157. Lagoe, M.B., Eyles, C.H., Eyles, N., and Hale, C., 1993, Timing of late Cenozoic tidewater glaciation in the far north Pacific: GSA Bulletin 105, n. 12, p. 1542 1560. Lagoe, M.B., and Zell ers, S.D., 1996, Depositional and microfaunal response to Pliocene climate change and tectonics in the eastern Gulf of Alaska : Marine Micropaleontology, v. 27, p. 121 140. Lisiecki, L.E., and Raymo, M.E., 2005, Pliocene Pleistocene stack of globally distr ibuted benthic stable oxygen isotope records : Paleoceanography, v. 20, PA1003, doi:10.1029/2004PA001071. Liu, J., Zhu, R., and Li, G., 2003, Rock magnetic properties of the fine grained sediment on the outer shelf of the East China Sea: implication for provenance : Marine Geology, v. 193, p. 195 206. Marinoni, L., Setti, M., Salvi, C., and Lopez Galindo, A., 2008, Clay minerals in late Quaternary sediments from the south Chilean margin as indicators of provenance and palaeoclimate : Clay Minerals, v. 43, no. 2, p. 235 253. Mayer, L.A., Gardner, J.V., Armstrong, A., Calder, B.R., Malik, M., Angwenyi, C., Karlpata, S., Montoro Dantes, H., Morishita, T., Mustapha, A., van Waes, M., Wood, D., and Withers, A., 2005, New views of the Gulf of Alaska Margin Mapp ed for UNCLOS applications: EOS Trans. AGU, v. 86, no. 52, Fall meeting supplemental abstract T13D 0500. McClennan, S.M., 1982, On the geochemical evolution of sedimentary rocks : Chemical Geology, v. 37, 335 350.

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94 McClennan, S.M., Bock, B., Hemming, S.R. Hurowitz, J.A., Lev, S.M., and McDaniel, D.K., 2003, The roles of provenance and sedimentary processes in the geochemistry of sedimentary rocks, in Lentz, D.R. (ed.), Geochemstry of Sediments and Sedimentary Rocks: Evolutionary Considerations to Mineral Deposit Forming Environments: Geological Association of Canada, GeoText 4, p. 7 38. McClennan, S.M., Hemming, S., McDaniel, D.K., and Hanson, G.N., 1993, Geochemical approaches to sedimenta tion, provenance, and tectonics: Geological Society of America Spe cial Paper 284, p. 21 40. McLennan, S.M., Bock, B., Compston, W., Hemming, S.R., and McDaniel, D.K., 2001, Detrital zircon geochronology of Taconian and Acadian Foreland sedimentary rocks in New England : Journal of Sedimentary Research, v. 71, no. 2, p. 3 05 317. McLennan, S.M., Taylor, S.R., McCullough, M.T., and Maynard, J.B., 1990, Geochemical and Nd Sr isotopic composition of deep sea turbidites: crustal evolution and plate tectonic associations : Geoch i mica et Cosmochimica Acta, v. 54, p. 2015 2050. Meigs A., and Sauber, J., 2000, Southern Alaska as an example of the long term consequences of mountain building under the influence of glaciers : Quaternary Science Reviews, v. 19, p. 1543 1562. Milliman, J.D., Snow, J., Jaeger, J.M., and Nittrouer, C.A., 1996, Catastrophic discharge of fluvial sediment to the ocean: evidence of Jokulhlaups events in the Alsek Sea Valley, southeast Alaska (USA), Erosion and Sediment Yield: Global and Regional Perspectives : Proceedings of the Exeter Symposium IAHS Publ. n o. 236. Molnar, P., and England, P., 1990, Late Cenozoic uplift of mountain ranges and global climate change: chicken or egg? : Nature, v. 346, p. 29 34. Morata, D., Higueras, P., Dominguez Bella, S., Parras, J., Velasco, F., and Aparicio, P., 2001, Fuchs ite and other Cr rich phyllosilicates in ultramafic enclaves from the Almaden mercury mining district, Spain : Clay Minerals, v. 36, no. 3, p. 345 354. Nath, B.N., Kunzendorf, H., and Pliueger, W.L., 2000, Influence of provenance, weathering and sedimentar y processes on the elemental ratios of the fine grained fraction of the bedload sediments from the Vembanad Lake and the adjoining continental shelf, southwest coast of India: J ournal of Sedimentary Research, v. 70, no. 5, p. 1081 1094. Nesbitt, H.W., and Young, G.M., 1984, Prediction of some weathering trends of plutonic and volcanic rocks based on thermodynamics and kinetic considerations : Geochimica et Cosmochimica Acta, v. 48, p. 1523 1534.

PAGE 95

95 Nesbitt, H.W., and Young, G.M., 1996, Effects of Chemical Wea thering and Sorting on the Petrogenesis of Siliciclastic Sediments, with Impl ications for Provenance Studies: Journal of Geology, v. 104, p 524 542. Perry, S.E., 2006, Thermochronology and provenance of the Yakutat terrane, southern Alaska based on fissi on track and U/Pb analysis of detrital zircon [M.S. thesis]: Albany, State University of New York at Albany, 167 p. Perry, S.E., Garver, J.I., and Ridgway, K.D., 2009, Transport of the Yakutat Terrane, Southern Alaska: Evidence from Sediment petrology and detrital zircon fission track and U/Pb double dating : Geology, v. 117, p. 156 173. Plafker G. and Berg, H. C., 1994, An overview of the geology and tectonic evolution of Alaska, in Plafker, G., and Berg, H.C. (eds.), The Geology of North America, Volume G 1: The Geology of Alaska : Geological Society of America. Boulder, CO, 1994, pp. 1055. Plafker, G., 1987, Regional geology and petroleum potential of the northern Gulf of Alaska continental margin, in Scholl, D.W., Grantz, A., and Vedder, J.G., (eds.), Petroleum geology potential of the continental margin of western North America and adjacent ocean basins: Circum Pacific council for Energy and Mineral Resources Earth Science Series, v. 6, p. 229 268. Plafker, G., Moore, J.C., Winkler, G.R., 1994, Geolog y of the southern Alaska margin, in Plafker, G., and Berg, H.C. (eds.), The Geology of North America, Volume G 1: The Geology of Alaska : Geological Society of America. Boulder, CO, 1994, pp. 1055. Rea, D.K., and Snoeckx, H., 1995, Sediment fluxes in the Gulf of Alaska; paleoceanographic record from Site 887 on the Patton Murray Seamount Platform: Proceedings of the Ocean Drilling Program, Scientific Results, v. 145, p. 247 256. Reece, R S., 2009, Erosion and Deposition by Cross Shelf Glacial Advance as a Mechanism for Channel inception in the Surveyor Fan : Gulf of Alaska, Geol. Soc. Abstracts w/Programs vol. 41, no. 7, p305, 108 20. Richter, D.H., Preller, C.C., Labay, K.A., and Shew, N.B., 2006, Geologic Map of the Wrangell Saint Elias National Park an d Preserve, Alaska : US Geological Survey Scientific Investigations Map 2877, scale 1:350,000. Risley, D.E., Martin, G.C., Lynch, M.B., Flett, T.O., Larson, J.A., and Horowitz, W.L., 1992, Geological report for the G ulf of Alaska planning area in Turner, R. F., ed., U.S. Minerals Management Service OCS Report MMS 92 0065, 302 p., 130 figs., 9 appendices. Roe, G.H., Stolar, D.S., Willett, S.D., 2006, Response of a steady state critical wedge orogen to changes in climate and tectonic forcing : Geological Society of America Special paper, 398, p. 227 239.

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96 Schoster, F., Behernds, M., Mueller, C., Stein, R., and Wahsner, M., 2000, Modern river discharge and pathways of supplied material in the Eurasian Arctic Ocean: evidence from mineral assemblag es and major and minor element distribution : International Journal of Earth Sciences, v. 89, p. 486 495. Singh, B., and Gilkes, R.J., 1991, Weathering of a chromia muscovite to kaolinite : Clays and clay minerals, v. 39, no. 6, p. 571 579. Smosna, R., Bru ner, K.R., and Burns, A., 1999, Numerical analysis of sandstone composition, provenance, and paleogeography : Journal of Sedimentary Research, v. 69, p. 1063 1070. Spear, F.S., and Pyle, J.M., 2002, Apatite, monazite and xenotime in metamorphic rocks : Reviews in Mineralogy and Geochemistry, v. 48, p. 293 335. Spotila, J.A., Buscher, J.T., Meigs, A.J., Reiners, P.W., 2004, Long term glacial erosion of active mountain belts: Examples of the Chugach St. Elias Range, Alaska: Geology, v. 32, n. 6, p. 501 5 04. Stevenson, A.J., and Embley, R., 1987, Deep sea fan bodies, terrigenous turbidite sedimentation and petroleum geology, Gulf of Alaska, in Scholl, D.W., Grantz, A., and Vedder, J.G., (eds), Geology and Resource Potential of the Continental Margin of Wes tern North America and Adjacent Ocean Basins Beaufort Sea to Baja California : Circum pacific Council for Energy and Mineral Resources, Houston, TX, p. 503 522. Swan A.R.H., and Sandilands, M., 1995, Introduction to Geological Data Analysis Blackwell Scie nce, University of California. 446 pp Taylor, S.R., and McClennan, 1981, The composition and evolution of the continental crust: rare earth element evidence from sedimentary rocks : Philosophical Transactions of the Royal Society London, v. 301, p. 381 39 9. Templ, M., Filzmoser, P., and Reimann, C., 2008, Cluster analysis applied to regional geochemical data: Problems and possibilities, Applied Geochemistry, v. 23, p. 2198 2213. Tomkin, J. H. and Roe, G.H., 2007, Climate and tectonic controls on glaciated critical taper orogens: Earth, Planet. Sci. Letts., v. 262, p. 385 397. Tomkin, J.H., 2007, Coupling glacial erosion and tectonics at active orogens: A numerical modeling study: J. of Geophysical Research Earth Surface, v. 112, F02015. Young, G.M., and N esbitt, H.W., 1998, Processes controlling the distribution of Ti and Al in weathering profiles, siliciclastic sediments and sedimentary rocks : Journal of sedimentary research, v. 68, no. 3, p. 448 455.

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97 Zachos, J.C., Shackleton, N.J., Revenaugh, J.S., Palik e, H., and Flower, B., 2001, Climate response to orbital forcing across the Oligocene Miocene boundary : Science, v. 292, no. 5515, p. 274 278. Zellers, S.D., 1995, Foraminiferal sequence biostratigraphy and seismic stratigraphy of a tectonically active mar gin; the Yakataga Formation, northeastern Gulf of Alaska : Marine Micropaleontology, v. 26, p. 255 271.

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98 BIOGRAPHICAL SKETCH Alex Ullrich was born in Essen, Germany, but grew up mostly in Clear Spring, Maryland, a town with two stoplights and a po pulation of about 500. He spent a lot of time as a child collecting fossils (mostly brachiopods and crinoids stems from that area of MD), and decided at 8 years old that he wanted to be a paleontologist. After graduating high school, Alex moved immediate ly to Boone, NC where he pursued a degree in g eology at Appalachian State University. In 2004, he was able to participate in a research cruise aboard the R/V Alpha Helix with his undergraduate advisor, Dr. Ellen Cowan. Here, he was introduced to Dr. Joh n Jaeger, and developed a strong interest in glacial sedimentology. After preparing an undergraduate thesis on high latitude foraminiferal ecology (that was eventually published in 2009 ), he graduated with a BA in g e ology and minors in German and b iology. During his final year at Appalachian State, Alex decided to take on graduate study, and applied to the University of Florida, so he could work with John Jaeger on his research in the Gulf of Alaska. When not involved with research, Alex has a very stron g interest in several martial arts and gymnastics, as well as ultralight aviation (when possible), and mountain biking.