Glacimarine Mudrock Provenance

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Title:
Glacimarine Mudrock Provenance Pb-Isotopic and Elemental Analyses of Different Grain Size Fractions in the Yakataga Formation, Southern Alaska
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1 online resource (1 p.)
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english
Creator:
Loss, Dylan P
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University of Florida
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Gainesville, Fla.
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Thesis/Dissertation Information

Degree:
Master's ( M.S.)
Degree Grantor:
University of Florida
Degree Disciplines:
Geology, Geological Sciences
Committee Chair:
Jaeger, John M
Committee Members:
Martin, Ellen Eckels
Foster, David A
Kamenov, George Dimitrov

Subjects

Subjects / Keywords:
geochemistry -- glacial-marine -- glacimarine -- glaciomarine -- mudrock -- pb-isotopes -- pca -- provenance -- sedimentology
Geological Sciences -- Dissertations, Academic -- UF
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Geology thesis, M.S.
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theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
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Electronic Thesis or Dissertation

Notes

Abstract:
Fine-grain strata are abundant in glacial environments where diamicts are found in both terrestrial and marine settings. Evaluating the utility of diamicts as records of glacial dynamics depends on analyzing particle composition. I examine provenance of mudrocks of the glacimarine Neogene Yakataga Formation of southern Alaska. The Yakataga is primarily composed of fine-grained diamictite, so previous detrital zircon analyses may provide an incomplete provenance story. I analyze the bulk sediment and silt fraction(15-63 µm) of mudrock Yakataga samples for elemental geochemistry and Pb isotopes. In addition I analyzed the silt fraction sediment for mineralogy using XRD. XRD analyses reveal three dominant mineral phases present in most of the silt samples: quartz, albite, and chlorite. Pb isotopic silt analyses reveal mixing of focused point sources while Pb isotopic bulk analyses indicate a more widespread uniform source. Elemental analyses are compared with published results from possible source rocks. Unconformable Yakataga sections,overlying Eocene-Cretaceous strata, have a higher proportion of mafic source components, while conformable sections have a higher proportion of felsic derived material. Provenance of mudrocks of the Yakataga is consistent with detrital zircon results. In addition to zircon results, the mudrock analyses provide stratigraphic context to provenance showing variation between sections. The difference between silt and bulk provenance signatures highlights the importance of utilizing consistent size fractions in mudrock analyses, as differences in mineralogy and sediment transport between the silt and clay fractions can lead to mudrocks made up of geochemically distinct size fractions and provenance records.
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In the series University of Florida Digital Collections.
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Includes vita.
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Includes bibliographical references.
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Description based on online resource; title from PDF title page.
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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 Dylan P Loss.
Thesis:
Thesis (M.S.)--University of Florida, 2013.
Local:
Adviser: Jaeger, John M.
Electronic Access:
RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2014-05-31

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lcc - LD1780 2013
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UFE0045439:00001


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1 GLACIMARINE MUDROCK PROVENANCE : PB ISOTOPIC AND ELEMENTAL ANALYSES OF DIFFERENT GRAIN SIZE FRACTIONS IN THE YAKATAGA FORMATION, SOUTHERN ALASKA By DYLAN PATRICK LOSS A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERS ITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2013

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2 2013 Dylan Patrick Loss

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3 To my Rock Collection

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4 ACKNOWLEDGMENTS I would like t o thank the Consortium for Ocean Leadership, STEEP, and SEPM for funding for this project. In addition, I would like to thank to my advisor, John, for guidance in my research. My committee: George, Dave, and Ellen have provided insight along the way. Georg been there to listen to my complaining. Tania, Kristen, and Kyle have all helped with lab work. JD helped with data processing in R. Discussions of lead isotopes with Dr. Mueller were helpful. I would like to thank t he office staff and all my friends, especially those that helped me when I was lost, literally. Finally, I have to thank my parents for being there since the beginning, 1989.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF TABLES ................................ ................................ ................................ ............ 7 LIST OF FIGURES ................................ ................................ ................................ .......... 8 LIST OF ABBREVIATIONS ................................ ................................ ........................... 10 ABST RACT ................................ ................................ ................................ ................... 12 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .... 14 2 BACKGROUND ................................ ................................ ................................ ...... 19 Geologic Setti ng ................................ ................................ ................................ ..... 19 Yakataga Provenance and Potential Sediment Sources ................................ ......... 22 Mudrock Provenance Tools ................................ ................................ .................... 24 3 METHODS ................................ ................................ ................................ .............. 28 Sample Collection and Selection ................................ ................................ ............ 28 Bulk Sample Preparation ................................ ................................ ........................ 28 Silt Sample Preparation ................................ ................................ .......................... 29 Silt XRD ................................ ................................ ................................ .................. 30 Geochemical Analyses ................................ ................................ ........................... 30 Data Analysis ................................ ................................ ................................ .......... 31 4 RESULTS ................................ ................................ ................................ ............... 32 Silt Mineralogy ................................ ................................ ................................ ........ 32 Elemental Geochemistry ................................ ................................ ......................... 32 Pb Isotopes ................................ ................................ ................................ ............. 36 5 DISCUSSION ................................ ................................ ................................ ......... 54 Establishing Mudrock Provenance ................................ ................................ .......... 54 Multivariate Data Analysis ................................ ................................ ....................... 56 Bulk Fraction Silt Fraction Comparison ................................ ................................ 60 Lead Isotopes ................................ ................................ ................................ ......... 63 Yakataga Provenance ................................ ................................ ............................. 66 Future Work ................................ ................................ ................................ ............ 69 6 CONCLUSIONS ................................ ................................ ................................ ..... 74

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6 APPENDIX A SILT SEM PHOTOGRAPHS ................................ ................................ ................... 76 B SILT MICROSCOPE PHOTOGRAPH S ................................ ................................ .. 88 LIST OF REFERENCES ................................ ................................ ............................. 113 BIOGRAPHICAL SKETCH ................................ ................................ .......................... 120

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7 LIST OF TABLES Table page 4 1 Silt XRD data modern Bering/Tana Glacier samp les Yakataga samples, and Kulthieth/Poul Creek samples. ................................ ................................ ............ 38 4 2 Bulk elemental data f or Yakataga and modern Bering/Tana Glacier samples. ... 40 4 3 Silt elemental data for Yakataga and modern Bering/Tana Glacier samples. ..... 42 4 4 Silt elemental data for Kulthieth and Poul Creek Formation silt samples. ........... 47 4 5 Bulk Pb isotopic data for Yakataga and modern Bering/Tana Glacier samples.. ................................ ................................ ................................ ............ 49 4 6 Silt Pb isotopic data for Yakataga and modern Bering/Tana Glacier samples. ... 50

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8 LIST OF FIGURES Figure page 1 1 Terrane and geologic map of the study area. Geological map adapted from Witmer (2009). ................................ ................................ ................................ .... 17 1 2 Measured sections of the Yakataga/Redwood formation. Adapted from Wi tmer (2009) ................................ ................................ ................................ ..... 18 4 1 SEM images a nd binocular microscope photographs of diss agregated Yakataga silt samples ................................ ................................ ......................... 51 4 2 Yakataga element al geochemistry spider diagrams ................................ ........... 52 4 3 Pb isotopic data ................................ ................................ ................................ .. 53 5 1 P rincipal component analysis (PCA) of unaltered elemental data from the di fferent possible source regions ................................ ................................ ........ 71 5 2 PCA of the bulk fraction Yakataga samples ................................ ....................... 72 5 3 PCA of the silt fraction Yakataga samples ................................ .......................... 73 A 1 SEM photograph of silt sample WI1 035 ................................ ............................ 76 A 2 SEM photogra ph of silt sample WI1 035. ................................ ........................... 77 A 3 SEM photograph of silt sample WI1 224. ................................ ........................... 78 A 4 SEM photograph of silt sample SV3 089. ................................ ........................... 79 A 5 SEM photograph of silt sample SV3 089. ................................ ........................... 80 A 6 SEM photograph of silt sample SV3 089. ................................ ........................... 81 A 7 SEM photograph of silt sample KM1 16. ................................ ............................ 82 A 8 SEM photograph of silt sample KM1 16. ................................ ............................ 83 A 9 SEM photograph of silt sample KM1 16. ................................ ............................ 84 A 10 SEM photograph of silt sample CY2 36. ................................ ............................. 85 A 11 SEM photograph of silt sample 07YA08. ................................ ............................ 86 A 12 SEM photograph of silt sample 07YA08. ................................ ............................ 87 B 1 Optical microscope photograph of silt sample 07YA08. ................................ ..... 88

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9 B 2 Optical microscope photograph of silt sample 07YA08. ................................ ..... 89 B 3 Optical microscope photograph of silt sample 07YA08. ................................ ..... 90 B 4 Optical microscope photograph of s ilt sample 07YA08. ................................ ..... 91 B 5 Optical microscope photograph of silt sample 07YA08. ................................ ..... 92 B 6 Optical microscope photograph of silt sample 07YA08. ................................ ..... 93 B 7 Optical microscope photograph of silt sample 07YA08. ................................ ..... 94 B 8 Optica l microscope photograph of silt sample 07YA08. ................................ ..... 95 B 9 Optical microscope photograph of silt sample 07YA08. ................................ ..... 96 B 10 Optical microscope photograph of silt sample KI1 209. ................................ ...... 97 B 11 Optical microscope photograph of silt sample KI1 209. ................................ ...... 98 B 12 Optical microscope photograph of silt sample KI1 209. ................................ ...... 99 B 13 Optical microscope photograph of silt sample KI1 209. ................................ .... 100 B 14 Optical microscope photograph of silt sample KM1 16. ................................ .... 101 B 15 Optical microscope photograph of silt sample KM1 16. ................................ .... 102 B 16 Optical microscope photograph of silt sample KM1 16. ................................ .... 103 B 1 7 Optical microscope photograph of silt sample KM1 16. ................................ .... 104 B 18 Optical microscope photograph of silt sample SV1 042. ................................ .. 105 B 19 Optical microscope photograph of silt sample SV1 042. ................................ .. 106 B 20 Optical microscope photograph of silt sample SV1 042. ................................ .. 107 B 21 Optical microscope photograph of silt sample SV1 042. ................................ .. 108 B 22 Optical microscope photograph of silt sample WI2 035. ................................ ... 109 B 23 Optical microscope photograph of silt sample WI2 035. ................................ ... 110 B 24 Optical microscope photograph of silt sample WI2 035. ................................ ... 111 B 25 Optical microscope photograph of silt sample WI2 035. ................................ ... 112

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10 LIST OF ABBREVIATIONS CMC Chugach Metamorphic Complex CPC Coast Plutonic Complex CPW Chugach Prince William Terranes CT Chugach Terrane CY Cape Yakataga DZFT Detrital Zircon Fission Track HFSE High Field Strength Elements ICP MS Inductively Coupled Plasma Mass Spectrometer IRD Ice Rafted Debris KI Kayak Island KM Kulthieth Mountain MORB Mid Ocean Ridge Basalt OV Orca and Valdez Groups PC Principal Component PCA Principal Components Analysis PWT Prince William Terrane REE Rare Earth Elements RPM Revolutions Per Minute SEM Scanning Electron Microscope STEEP ST. Elias Erosion and tectonics Program SV Samovar Hills UCC Upper Continental Crust WCT Wrangell Composite Terrane WI Wingham Island

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11 XRD X Ray Diffraction YM Yakutat Microplate

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12 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Master of Scie nce GLACIMARINE MUDROCK PROVENANCE : PB ISOTOPIC AND ELEMENTAL ANALYSES OF DIFFERENT GRAIN SIZE FRACTIONS IN THE YAKATAGA FORMATION, SOUTHERN ALASKA By Dylan Patrick Loss May 2013 Chair: John Jaeger Major: Geology Fine grain strata are abundant in glaci al environments where diamicts are found in both terrestrial and marine settings. Evaluating the utility of diamicts as records of glacial dynamics depends on analyzing particle composition. I examine provenance of mudrocks of the glacimarine Neogene Yakat aga Formation of southern Alaska. The Yakataga is primarily composed of fine grained diamictite, so previous detrital zircon analyses may provide an incomplete provenance story. I analyze d the bulk sediment and silt fraction (15 samples for elemental geochemistry and Pb isotopes. In addition I analyzed the silt fraction sediment for mineralogy using XRD. XRD analyses reveal three dominant mineral phases present in most of the silt samples: quartz, albite, and chlorite. Pb isotopi c s ilt analyses reveal mixing of focused point sources while Pb isotopic bulk analyses indicate a more widespread uniform source. Elemental analyses are compared with published results from possible source rocks. Unconformable Yakataga sections, overlying Eocene Cretaceous strata, have a higher proportion of mafic source components while conformable sections have a

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13 higher proportion of felsic derived material. Provenance of mudrocks of the Yakataga is consiste nt with detrital zircon results In addition t o zircon results, the mudrock analyses provide stratigraphic context to provenance showing variation between sections. The difference between silt and bulk provenance signatures highlights the importance of utilizing consistent size fractions in mudrock an alyses, as differences in mineralogy and sediment transport between the silt and clay fractions can lead to mudrocks made up of geochemically distinct size fractions and provenance records.

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14 CHAPTER 1 INTRODUCTION Glacimarine sediments are widespread in t he global sedimentary record, and understanding the provenance of glacial sediments can reveal the tectonic and climatic history of a region. Previous provenance studies of glacimarine sediment have focused on the coarse fraction, from sand through boulder s assumed to represent ice rafted debris, and have generally applied elemental (Young and Nesbitt 1999) and isotope geochemistry (Hemming et al. 1998; Pierce et al. 2011), detrital zircon spectra, and petrographic techniques (Perry et al. 2009; Roy et al. 2009; Witmer 2009). However, glacial diamicts, especially those derived from temperate glaciers, have a substantial mud (silt + clay) size fraction (Eyles et al. 1991; Eyles et al. 1983; Miall 1985; Witmer 2009). Provenance studies focusing only on the coa rser fractions may not tell a complete erosion story from glacial or tectonic settings. In sediments where there is indication of multiple zircon sources of different ages, detrital zircon analyses can fail to differentiate recycling from primary weatherin g. Geochemical analyses could better distinguish the sources if the protoliths are of varying mafic felsic composition. Mud fraction provenance tools also can be useful in studying samples from drilling where the recovery of the unlithified coarser size fr action is often much lower than the mud fraction. Here I analyze the provenance of the mud fraction of the glacimarine Yakataga formation exposed in thrust sheets in the foothills of the Chugach St. Elias Mountains on the coast of Southern Alaska. The Chu gach St. Elias Mountains are the highest coastal mountain range on earth and contain the most active temperate glacial system on the planet (Gulick et al. 2004; Hallet et al. 1996; Headley et al. 2012; Jaeger et al. 2001). Uplift in the range is

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15 driven by flat slab subduction of the Yakutat microplate (Finzel et al. 2011), on which the Yakataga Formation exists ( Figure 1 1 ). Deposition of the Yakataga Formation began at 5.6 Ma and continues through present day, recording the glacial and tectonic history of the region (Lagoe et al. 1993). Increases in Pleistocene sediment accumulation rates offshore in the Gulf of Alaska are attributed to a regional increase in glacial coverage corresponding to the global transition to 100 ka glacial periods (Berger et al. 20 08; Rea and Snoeckx 1995). However, late Neogene convergence, exhumation, and uplift along the leading edge of deformation on the Yakutat microplate may also be a driver of the increased offshore sediment delivery. Provenance studies of onshore and offshor e exposures of the Yakataga are lacking that delineate between these two scenarios, and have been limited to provenance of the coarse fraction constrained using detrital zircon spectra (Perry et al. 2009; Witmer 2009). These results indicate that the prima ry sources of coarser Yakataga sediment are recycling of the sedimentary rocks on the backstop of accretion (Chugach Prince William Terrane) and the exhuming sediment cover on the microplate (Kulthieth and Poul Creek). However, the Yakataga is primarily c omposed of fine grain sediment ( Figure 1 2), and the periglacial and glacimarine processes that deliver sediment to the ocean likely differ for sandier, coarser deposits sampled for detrital zircon analyses versus those that release large quantities of mud (tidewater, glacifluvial discharge) (Powell and Molnia 1989). Complementary studies of coarse (zircon) and fine grain sediment provenance are few, and the advancements in elemental and isotope geochemistry of mudrocks (Barbera et al. 2009; Lamaskin et al 2008) make it possible to better develop holistic provenance analyses for heterolithic sedimentary facies.

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16 This study uses a combination of established and novel mudrock provenance tools. Within the mud fraction I focus on silt size material, 15 associated with analyzing clay size material for provenance (Dinelli et al. 2007), and I com pare these measurements to the parent bulk mudrock sample to demonstrate potential differences in provenance when only the silt fraction is analyzed. To analyze the fine fraction of the Yakataga I use XRD mineralogy, elemental geochemistry, and Pb isotopes In addition to Yakataga samples, I analyze lower Yakutat terrane silt samples as a possible source and clearly glacially derived modern samples that can be attributed to a particular range in bedrock sources. To interpret the data, I employ principal com ponents analysis that includes both sample and end member elemental data to resolve potential sources (Barbera et al. 2009; Bhatia and Crook 1986).

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17 Figure 1 1. Terrane and geologic map of the study area. A. Map of the general study area in southern Alaska showing the 3 most recently accreted terranes: Wrangellia (WCT), Chugach/Prince William (CPW), and the Yakutat Microplate (YM). Yakatut Microplate/North America collision is 54 mm/yr (ref), leading to the uplift of the St. Elias orogen. B. Geologic map of the study area, location shown in panel A. The focus of this study is on the Yakataga and Redwood formations (purple). The orange and blue circles indicate locations of measured sections corresponding to drafted sections of Figure 2 and from which c ame samples used in this study The relative colors for each section are continued throughout the figures (i.e. samples from sections with an orange circle will have orange color in all other figures). Geological map adapted from Witmer (2009).

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18 Figure 1 2. Measured sections of the Yakataga/Redwood formation. See Figure 1B for section locations. The sections can be divided into two general groups based on basal lithostratigraphic contacts. Blue sections have a conformable contact with the underlying Pou l Creek formation below. Orange sections have an unconformable or obscured basal contact with the older Kulthieth formation or Yakutat groups. Adapted from Witmer (2009).

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19 CHAPTER 2 BACKGROUND Geologic Setting The southern Alaska margin is an active tecto nic zone that includes a series of accreted terranes ( Figure 1 1 ). In this study I will be discussing the three most recently accreted terranes: the Cenozoic Yakutat terrane (on the Yakutat microplate), the Mesozoic Early Cenozoic terranes including the Ch ugach and Prince William (combined as the CPW) and the late Paleozoic Mesozoic Wrangellia terrane (WCT) ( Figure 1 1) (Plafker et al. 1994; Plafker et al. 1989; Witmer 2009). The main focus of this study is the Yakutat terrane (interchangeable with Yakutat microplate here). At approximately ~40 Ma, flat slab subduction of the Yakutat terrane under the North American Plate was initiated and continues to present with a plate velocity relative to north America of 4 5 cm/year (Chapman et al. 2012; Finzel et al. 2011). This subduction maintains the accretionary flux of the St. Elias/Chugach orogen. The Yakutat terrane is allocthonous and has been transported a distance of 600 km along the Queen Charlotte Fairweather transform system during the Cenozoic with contin ued deposition during transport (Perry et al. 2009). The microplate initially formed near the latitude of Prince Rupert of North Central British Columbia and later migrated northward before colliding with the Southern Margin Composite terrane backstop base d on detrital zircon dating in the sand size fraction of the Yakutat terrane (Perry et al. 2009; Witmer 2009). Three main lithostratigraphic units comprise the Yakutat, which unconformably overlie the Orca Group of the Prince William Terrane and the Creta ceous Yakutat Group. The oldest formation is the middle Eocene Kulthieth (55.8 33.9 Ma). It is mostly arkosic in composition interpreted to have been formed in non marine alluvial plain, and

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20 migrating through delta plain, barrier beach, and shallow marine settings containing interbeds of coal (Perry et al., 2009). Overlying the Kulthieth formation is the lower Miocene Poul Creek Formation (33.9 23.0 Ma). It represents a marine transgression consisting of argillaceous, organic rich, and glauconitic sediments (Perry et al. 2009; Plafker et al. 1994). Detrital zircon fission track (DZFT) ages of Kulthieth and Poul Creek Formation sediments indicates they were sourced by Tertiary cooled northern granodioritic CPC plutons while the Yakataga has younger DZFT ages representing its formation after the Yakutat microplate collided with Alaska and the CPW became an important source (Perry et al. 2009). The uppermost and most relevant formation for this study is the Yakataga (~5.6 Ma Present) (Lagoe et al. 1993). In th e western part of the study area the Redwood Formation outcrops at Wingham Island ( Figure 1) and is equivalent in age and depositional environment to the western stratigraphic sections of the Yakataga Formation (Witmer 2009). The two formations are referre d to together as the Yakataga here. It is composed of marine strata with intervals containing ice rafted debris (IRD), dropstones and diamictites, documenting its predominantly glacial genesis ( Figure 1 2) (Eyles et al. 1991; Perry et al. 2009; Plafker et al. 1994; Witmer 2009). The upper Yakataga shows evidence for fjord facies that likely would reflect a focused sediment source (Eyles et al., 1991). The basal contact of the Yakataga is variable depending on geographic region. A large unconformity is deve loped in the eastern part of the study area near the syntaxis of the St. Elias orogeny; the syntaxis is concentrated north of the Malaspina Glacier ( Figure 1 1)(Chapman et al. 2012). The unconformity is angular and erosional with up to

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21 5 km of strata missi ng. Some sections have just the Poul Creek missing with the Yakataga overlying the Kulthieth; at the maximum extent of the unconformity at Samovar Hills, the Yakataga sits directly on top of the Yakutat Group ( Figure 1 2) (Chapman et al. 2012; Witmer 2009) However, many of the stratigraphic sections of the Yakataga, including those in the western part of the study area and at Cape Yakataga, conformably overlie the Poul Creek Formation. Hereafter, these groups will be referred to as the unconformable (gener ally eastern) and conformable (generally western) stratigraphic sections. The conformable Yakataga was buried approximately 5 7 km and exhumed while the unconformable sections were buried <2km prior to exhumation (Witmer 2009). This implies that the sedime nts exposed in the unconformable sections are depositionally younger than those of the conformable sections. The chronostratigraphy of the Yakataga is lacking with the only constrained age being the base of the Cape Yakataga section at 5.6 Ma (Lagoe et al. 1993). Biostratigraphic data is sparse and there is disagreement between different taxa, which have been shown to exhibit recycling (Lagoe et al. 1989; Marincovich 1990). The CPW ( Figure 1 1) consists of the accreted Mesozoic Early Cenozoic terranes that are south of the Border Ranges fault and form the accretional backstop to the Yakutat Terrane (Berger et al. 2008; Plafker et al. 1994). They consist mainly of deep marine rocks and are divided into the Chugach terrane, Prince William terrane, and Ghost Ro cks formation. The ultimate provenance of most of the sedimentary rocks in the terranes has been constrained to weathering of the CPC and Precambrian crustal rocks that have been intruded by the CPC (Farmer et al., 1993; Haeussler et al., 2006). The CPW ma kes up one of the largest accretionary complexes in the world. Out of

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22 these, the Chugach terrane is the oldest and volumetrically largest. It consists of a wide variety of accretionary events and rock types that fall into 4 main categories: a flysh and bas alt assemblage, a mlange assemblage, a glaucophanic greenschist assemblage, and a 600 km long metabasite belt outcropping at its southern border (Bruand et al. 2011; Gasser et al. 2011; Plafker et al. 1994; Plafker et al. 1989). These accreted from late T riassic through late Cretaceous and are fault bounded in the north and south. The core of the Saint Elias range is included in this terrane. The rock types of the Chugach terrane are mapped together as the Valdez Group of Figure 1 1 The metamorphic rocks of the Chugach are commonly called the Chugach Metamorphic Complex (CMC) and formed in a metamorphic event that peaked between 50 and 55 Ma (Gasser et al. 2012). The Prince William terrane accreted later in the Paleocene Early Eocene and largely consists o f the Orca Group. These are described as mostly being magmatic arc sourced rocks of mafic composition (Dumoulin 1987). The Ghost Rocks formation is much smaller than the others and is age equivalent to the Prince William terrane (Plafker et al. 1994). 40 Ar / 39 Ar dating of micas in the CPW constrains their metamorphic age to ~15 50 Ma, (Gasser et al. 2011) which is younger than their depositional age from biostratigraphy indicating resetting during metamorphism. Rocks of the CPW are intruded by the Sanak Bara nof plutonic belt, a tonalite trondhjemite granodiorite suite emplaced between 49 and 54 Ma (Sisson et al. 2003) formed by melting of Chugach accretionary prism sediments (Hudson et al. 1979). Yakataga Provenance and Potential Sediment Sources The coarse fraction provenance of the Yakataga has been constrained by detrital zircon ages to be a mixture from the CPW, the Chugach Metamorphic Complex, young plutons of the Sanak Baranof belt in southern Alaska, and the marine sediments of the

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23 Yakutat terrane, inc luding the Kultieth and Poul Creek Formations as well as recycling upon itself (Perry et al. 2009; Witmer 2009). Limited elemental work has been performed on bulk samples from the mudrocks from the Yakataga that indicate a mixed provenance from the units o f both the Yakutat and Southern Margin Composite Terrane (Ullrich, 2010). The metabasite of the CMC is important for this study as the geochemical data of Bruand et al. (2011) provide one potential end member source (mafic), in which one of the largest tem perate ice fields (Bagley) currently resides ( Figure 1 1 ). The Sanak Baranof plutonic belt is more localized in surface exposure, and elemental data from it is presented as a predominantly felsic crystalline end member (Sisson et al. 2003). A possible mud rock source for the Yakataga is direct weathering of the Coast Plutonic Complex (CPC) of British Columbia and southeastern Alaska. Plutons of the CPC are predominantly granodiorite and granite. Weathering of the CPC provided the sediment of the Kulthieth a nd Poul Creek (Perry et al. 2009). Here, elemental analyses of the Kulthieth/Poul Creek Formation silt will be used as a provenance end member, representing a recycled sedimentary source from the CPC. In addition to the sedimentary samples from the Yakutat published elemental data from Orca and Valdez formation graywackes and argillites are included in data analyses as additional sources. The Wrangellia terrane is also a possible mudrock source for the Yakataga ( Figure 1 1 ). However, its location inland of the Southern Margin Composite terrane makes it less likely to be a significant source. The type Wrangellia terrane is Pennsylvanian basement andesite overlain by Jurassic Cretaceous basinal strata (Plafker et al. 1989). Also in the southern Wrangellia ter rane are the Miocene Wrangell

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24 Mountains composed of basaltic magmas (Trop et al. 2012). Witmer (2009) observed zircons with an age range of ~65 190 Ma within the Yakataga that are derived from CPC associated plutons emplaced into the Wrangellia terrane. No geochemical data from this terrane are included in this study. Mudrock Provenance Tools Provenance studies of mudstones/and or mud sized bulk sediment using elemental and/or isotopic analyses have been successful in distinguishing source region and tecton ic setting (Barbera et al. 2009; Bhatia and Crook 1986; Dinelli et al. 2007; Farmer et al. 1993; Garver and Scott 1995; Lamaskin et al. 2008; McDaniel et al. 1997; McLennan 2001). Mudstones are the most common sedimentary rock on earth and provenance studi es have been applied in a variety of tectonic settings. Lamaskin et al. (2008) used mudrock elemental geochemistry to reconstruct the Triassic paleogeography of western North America. McDaniel et al. (1997) used isotopic analyses of muddy sediment in the A mazon fan to show the ultimate source of the sediments is the Andean highlands and that they have not experienced much weathering during transport through the Amazon basin. When analyzing mudrocks, the size fraction used in the analysis is necessary to con sider. In highly indurated and cemented samples, the separation of size fractions is not possible (Lamaskin et al. 2008). However, silt and clay size fractions can be separated when the sediments have not been buried deeply, as is the case with the Yakata ga (Witmer 2009), or are relatively modern sediments (Hemming et al. 1998; Innocent et al. 2000). Consideration of the size fraction of fine grained sediments analyzed is important because there are different mineral (and consequently elemental and isotopi c) assemblages within the clay

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25 diagenetic influences, which can alter certain iso top ic systems used for p rovenance studies (e.g., Nd Sm; Farmer et al. 1993 ), and thus do no t maintain source geochemistry as well as the silt fraction (Cullers 1988; Dinelli et al. 2007). Within the silt becomes cohesive and flocculates with clay size minerals (Curran et al. 2004) while the silt f raction (Innocent et al. 2000) The silt size fraction has been shown to best maintain source geochemistry and indicate provenance with granitic source material (Cullers 1988). Studies have used argon argon dating tools on the sortable silt fraction for provenance with success although the use of these techniques depends on the significant presence of potassium bearing minerals (VanL aningham et al. 2006). Because of the differences between mineralogy and particle behavior, it has been found that some elements tend to concentrate in certain size fractions (Dinelli et al. 2007). Examples of this include Zr concentrating in zircons in t he sand fraction and Rb in illite of the clay fraction. Elements that tend not to vary with size fraction are Cr and Ni (Dinelli et al. 2007). Cr has been used as a redox indicator in shales when it is present in amounts higher than its terrigenous source provides (Piper and Link 2002). In addition to grain size partitioning, some high field strength elements (HFSE) experience less depletion and enrichment from source to deposition (Zr, Y, La, Nb, Ti, Co, Cr, Ni, and Ce) (Barbera et al. 2009). Focusing on t hese elements in provenance studies can lessen concerns over diagenetic effects. Isotopic tracers, such as Nd, Sr, and Pb, are also used in mudrock provenance studies with varying success. In Alaska, Farmer et al. (1993) established the CPC

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26 provenance for the Orca and Valdez using a combination of elemental and Pb isotopic analyses. Depending on the mineralogy of the sample, Pb isotopic measurements may be a more accurate of a provenance indicator than Sr or Nd isotopic systems. Nd isotopic ratios represent the time since partitioning from the mantle, so large variations in ages of source terranes is ideal (Najman 2006). In the case where source rocks are of widely varying age (e.g., north Atlantic; Antarctica, Himalaya), Nd isotopic analyses of mudrocks may be able to distinguish between sources (Hemming et al. 1998). However, Nd isotopic measurements of offshore time equivalents to the Yakataga (Ve rvoort et al. Nd range (~ 6 units) compared to onshore sediments of the same source terranes (Cameron and Hattori 1997). Nd isotopes are often paired with Sr isotopic values to determine provenance (Hemming et al. 1998). However, beca use of partitioning during fluvial transport, the isotopic composition of Sr delivered to the ocean may reflect only the parts of orogens closest to the ocean (Cameron and Hattori 1997). In contrast, Pb isotopes have been shown to reflect long travel dist ance from sources with little change in isotopic ratio throughout the duration of fluvial travel (McDaniel et al. 1997). Of the common minerals, Pb is relatively abundant in feldspars, and provenance studies measuring Pb isotopes in feldspar have been succ essfully used in both Paleozoic and modern glacially derived sediments in Antarctica (Flowerdew et al. 2012a; Flowerdew et al. 2012b). Isotopic measurements of feldspar are advantageous for provenance studies because feldspars are more ubiquitous rock comp onents but feldspar will weather more quickly than zircon and is less likely to reflect a recycled sedimentary source. (Flowerdew et al. 2012b). Single grain analyses of silt and sand sized K feldspars have been used to characterize provenance and

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27 reconst ruct drainage patterns of Himalayan rivers (Alizai et al. 2011; Clift et al. 2008). Clift et al. (2008) analyzed bulk sediment Pb isotopes and found that they did not reflect the same variation seen in single grain feldspar isotopes. They concluded that Pb isotopes of bulk sediment are not an accurate provenance tool. Lastly, when interpreting a large amount of data of different types for single samples (~trace and major elements and isotopes) multivariate data analysis techniques can be useful to identify significant trends and associations of elements in mudrocks (Barbera et al. 2009; Bhatia and Crook 1986). Barbera et al. (2009) used PCA to show relative elemental associations that could be linked to rock types (e.g., La, Nb, and Zr correlate positively, but correlate negatively with Ni and Co), which help ed them to distinguish between the different tectonic source of the shales. Principal component analyses have also been applied to deep sea sediment mineralogy to map out variations in glacial prove nance (Andrews and Eberl 2011).

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28 CHAPTER 3 METHODS Sample Collection and Selection Samples were collected as part of the St. Elias Erosion and tectonics Program (STEEP) (Witmer 2009). Samples from the age equivalent Yakataga and Redwood formations are analyzed here (Witmer 2009). For this study, samples from five different stratigraphic sections of Yakataga/Redwood were chosen: Samovar Hills (SV), Kulthieth Mountain (KM), Cape Yakataga (CY), Wingham Island (WI), and Kayak Island (KI). SV and KM make up the unco nformable sections with CY, WI and KI making up the conformable sections. The Redwood Formation samples come solely from WI while the Yakataga samples come from all five sections. In total, 29 Yakataga formation samples are analyzed including four from the Redwood formation. In addition to the Yakataga samples, 12 samples from the older Yakutat terrane formations are analyzed: the Kulthieth formation, Poul Creek formation, and Yakutat Group. The samples analyzed were selected because they are the least indu rated of the mudrock samples of the Yakutat terrane, making separation of the silt fraction easier. In addition to the Yakutat terrane samples, 3 samples taken from outflow of the Bering and Tana Glaciers are included (Enkelmann et al. 2010). These samples are included to compare Yakataga samples with clearly glacially derived samples that can be attributed to a particular range in bedrock sources. Bulk Sample Preparation Eleven of the Yakataga/Redwood samples and the three modern samples were processed for bulk whole rock analyses. Indurated samples were powdered using a shatter box.

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29 Silt Sample Preparation The sortable silt size fraction, 15 other Yakutat terrane samples. To avoid any sediment that could potentia lly be transported along with the clay size sediment, the indurated samples had to be gently disaggregated. This was done by repeat edly vacuum drawing water into samples that had been lightly pulverized to coarse sand sized fragments in an agate mortar followed by repeated cycles of freezing and thawing (Cowan et al. 2012; Yang and Aplin 1997). The force of crystallization of the free zing water in the pore spaces slowly breaks down the larger fragments. Approximately 25 grams of sample was broken up using a mortar and pestle to 2 4 mm pieces. This was then placed in a 60 ml glass jar filled with deionized water to ~2 5 mm above the sam ple. Samples were then placed under vacuum at 27 in Hg for 1 hour. Following the release of the vacuum, the samples were immediately frozen. Once completely frozen, the samples were moved to an oven at ~80 C until completely thawed. The vacuum freeze thaw cycle was repeated for each sample between 10 and 14 times until a cloudy suspension was present, indicating the separation of clay and fine silt sized sediment. Once the disaggregation process was complete, the samples were wet sieved to less tha while particularly clay rich samples were allowed to settle before siphon ing off the clay nylon filter (manufactured by BioDesign) to remove any remaining sediment finer than

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30 the sortable silt. Finally, the samples were centrifuged 3 times in deionized water to remove any calgon solution and dried down at 90 C. Silt XRD XRD analyses on the silt fraction can be useful in determining the presence of primary rock forming minerals (Poppe et al. 2001). Samples from the Yakataga/Redwood and other Yakutat terrane s amples were analyzed at University of Florida using a Rigaku Ultima IV XRD, using a Cu K alpha beam (1.5418 ) and focusing beam geometry. The dried samples were sprinkled on a zero background silica sample holder and analyzed 3 times at a step size of 0.0 2 for 0.5 seconds per step from 5 quantitative) mineralogy using the whole pattern fitting routine in MDI Jade 9 software. Geochemical Analyses All silt samples were powdered in an agate mortar a nd pestle for geochemical analyses. Some samples appeared to have organic matter present so all samples were ashed at 550 C for 5 hours to remove organic material. Samples were processed for elemental analyses at University of Florida (Kamenov et al. 2009 ). Trace and major elements of all samples were measured on an Element2 ICP MS. Trace element errors are approximately 5% (Kamenov et al. 2009). Cation exchange column chemistry was used to concentrate Pb for isotopic analysis. Pb isotopes of Yakataga bulk and sil t samples were measured on a Nu MC ICP MS. Long term analysis of the NBS 981 Pb isotope standard yielded the following average values: 206Pb/204Pb=16.937 (+/ 0.004, A sa mple of calgon solut ion was also analyzed on the Nu MC ICP MS to check for possible Pb contamination. It was determined that the calgon had ~20 ppt Pb and thus

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31 would have no effect on the silt Pb data. No other reagents were used in processing the silt oth er than pure deionized water so Pb contamination during sample preparation is not assumed to have occurred. Data Analysis Multivariate data analysis was performed using the R statistical computing package (R Development Core Team, 2008). Due to the closed sum nature of elemental data, a log ratio transform was applied to the data (Aitchison 1982).

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32 CHAPTER 4 RESULTS Silt Mineralogy Results of semi quantitative XRD silt analyses are shown in Table 4 1. The mineralogical content varies between sample; howeve r, the majority of samples are dominated by three main mineral phases: quartz, albite, and clinochore. Figures 4 1A and 4 1B show SEM images of Yakataga silt samples annotated with minerals indicated by XRD identified through grain morphology. When viewed under stereographic microscope, other minerals are visually present that are below detection limits (< a few %) in XRD analyses ( Figure 4 1). Visually identified minerals include amphiboles and other green brown ferromagnesian minerals. The relatively smal l quantities of clay minerals present visually and in XRD analyses indicate that the vacuum disaggregation successfully allowed the silt fraction to be isolated. Raw XRD data for all 44 samples is available in a zip file from the University of Florida Data Collection http://ufdcimages.uflib.ufl.edu/IR/00/00/19/94/00001/Loss_XRD_Text_Data.zip Elemental Geochemistry Figure 4 2 shows six spider diagrams of elemental g eochemistry for the Yakataga and Bering/Tana Glacier bulk and silt sized (15 (Table 4 2 and 4 3 respectively). Figures 4 2A, 4 2C, and 4 2E show a selection of trace elements commonly presented in geochemical studies (Kamenov et al. 2009). Figures 4 2B, 4 2D, and 4 2F show a set of HFSE (Zr, Y, La, Nb, Ti, Co, Cr, Ni, and Ce) thought to retain original source rock geochemistry more effectively than other elements (Barbera et al. 2009; Dinelli et al. 2007). Analyses for bulk sediment ( Figure 4 2A and 4 2B) and silt ( Figure 4 2C and 4 2D) are normalized to mid ocean ridge basalt ( MORB )

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33 ( ). Analyses are normalized to MORB rather than the North American Shale Composite or Upper Continental Crust because I am analyzi ng sediments that are potentially sourced by altered oceanic crust not by shales. Normalizing to MORB has been used in past mudrock provenance analyses ( Lamaskin et al. 2008 ). In addition to Yakataga and modern glacial samples, Figures 4 2A D display the average continental arc signature (Rudnick and Fountain 1995) and lower Yakutat terrane silt analyses from this study. Figures 4 2E and 4 2F shows bulk divided by silt values to compare the different size fractions to examine for elemental enrichment/deple tion in the silt fraction. The method of disaggregation does not allow for quantitative grain size analysis so it is assumed that the majority of the non silt bulk rock sample is clay sized material as determined visually from hand sample observations. Thi s assumption will further be demonstrated in the discussion of Pb isotopic results. The bulk sediment trace element spider diagram ( Figure 4 2A) shows that most Yakataga and modern glacial samples follow a pattern similar to the continental arc signature. Separation between the stratigraphic sections is seen particularly with the unconformable sections being lower in Zr and Hf indicating they have less zircon. On the bulk sediment unaltered element diagram ( Figure 4 2B), the unconformable sections plot clos er to MORB indicating they have a more mafic source The unconformable sections are more enriched in Co, Cr, and Ni and more depleted in La and Ce than samples from the conformable sections. The silt sized fraction trace element spider diagram ( Figure 4 2 C) has a similar enrichment/depletion pattern as the bulk elemental trace element diagram pattern

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34 ( Figure 4 2A) with the exception of Pb and Zr which are highly enriched and depleted respectively, when compared to MORB The higher value of Pb in the silt is assumed to be from Pb substitution for K or Ca in the abund ant albite of the silt fraction The modern Bering/Tana glacier samples are similar to the Yakataga but do not have the high Pb anomaly. The depleted Zr in the silt samples likely indicates that zircon in the sand fraction has been effectively removed from the samples and the silt fraction has been adequately separated. The silt fraction unaltered trace element diagram ( Figure 4 2D) shows a similar pattern to the bulk fraction unaltered trace ele ment diagram. In the silt, separation between the groups of Yakataga stratigraphic sections is also more apparent, with samples from the unconformable sections having a more arc like signature and most elements being closer to the MORB standard In the bu lk/silt fraction normalized spider diagram for the wide suite of elements ( Figure 4 2E), most elements are very similar between the two fractions with the notable exception of Pb, which is highly enriched in the silt fraction compared to the bulk rock. Sam ples from the two Yakataga stratigraphic sections show some differentiation in this diagram indicating that most of the conformable section samples are more enriched in most elements in the bulk fraction relative to silt while the unconformable section sam ples are closer to being equivalent. This overall differentiation between the two stratigraphic sections may reflect a different source for each and/or a difference in grain size and mineralogy. In the bulk/silt fraction normalized spider diagram for unal tered elements ( Figure 4 2F), most elemental concentrations are close to equal between the size fractions and little difference exists between the groups of sections, with the exception that

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35 conformable samples tend to be enriched in Zr and Ce in the bulk fraction. The HFSE will be a more accurate indicator of provenance because they are not affected by grain size difference s between the stratigraphic sections. Included in Figures 4 2A D are average results for the Kulthieth and Poul Creek formation silt fr action samples from this study (Table 4 4). Mostly the Kulthieth and Poul Creek silt fraction samples follow a similar pattern to Yakataga samples. The most notable exception is that the Sr concentra tion in Kulthieth bulk and silt ( Figure 4 2C) is lower th an the Yakataga and the Kult h ieth and Poul Creek silt samples are closer in composition with the conformable Yakataga section samples than the unconformable section samples ( Figure 4 2D). The bulk Yakataga samples are enriched in Zr compared to the Kulthie th and Poul Creek silt samples most likely due to the lack of zircon in the silt fraction. The unconformable section sam ples are notably enriched in Cr, and Ni relative to Kulthieth and Poul Creek silts. In both Figure 4 2A and 4 2B, the modern Bering/Tana Glacier samples (black) follow the same pattern as the Yakataga samples but show more variation, probably due to having smaller individual source regions than is as sumed for the outcrop samples. The Bering Glacier samples (07YA08 and 07YA09) most likely w ere derived from erosion of the Poul Creek and Kulthieth Formations that the Bering Glacier overrides in the samples vicinity. The Tana Glacier sample (6EUT46) is from the north side of the Bagley Ice Field and sits atop one of the Sanak Baranoff plutons a nd the CMC in the near vicinity (Headley et al. 2013) The variation in local bedrock between the sample locations can explain the geochemical variability in the modern samples. Modern Bering/Tana glacier outwash sediment samples show a similar trend in mo st

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36 elements to the Yakataga samples with the notable exception of Pb in the silt fraction. Pb in the modern samples is closer to MORB values than the heavy enrichment in Yakataga silts. Duplicate analyses were performed on 10 of the Yakataga silt samples using separate dissolutions of the sample powders (Table 4 3). Most elements were consistent between the duplicate analyses with the exception of Zr, which showed slight differences in two of the duplicate samples, most likely indicating that the dissolved aliquots had differences in the amount of zircon. Duplicate analyses may have slight inaccuracies due to not labeling the different aliquots of sediment leading to slightly incorrect dilution factors. This caused some error in calculation of trace element abundances and is seen most in sample SV3 070. SV3 070 is the unconformable section outlier seen in the trace element spider diagram of Figure 4 2E and 4 2F. Samples with duplicate analyses were not analyzed for Pb isotopes or used in the PCA. Pb Isotopes Pb isotopic analyses are presented in Tables 4 5 (Bulk) and 4 6 (Silt). Figure 4 3 shows the results of Pb isotope analyses of the Yakataga Formation and modern Bering/Tana glacier sediment. Figures 4 3A and 4 3C show Pb isotopic results from potential se diment source s to the Yakutat microplate (Farmer et al. 1993). Fields from Farmer et al. (1993) are for isotopic values at age 50 Ma, so they had to be corrected to modern values to compare with our data. The Pb isotopic fields for the source terranes were corrected by plotting the modern Orca/Valdez sediment isotopic values of Farmer matched present day values of the Orca/Valdez. The bulk sediment analyses plot withi n the CPC and Orca/Valdez groups in both the 208 Pb/ 204 Pb versus 206 Pb/ 204 Pb ( Figure 4

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37 3A) and 207 Pb/ 204 Pb versus 206 Pb/ 204 Pb ( Figure 4 3C) plots, but the silt samples plot outside of the CPC field in both isotopic ratios. Figure 4 3A shows that the silt va lues plot towards the Wrangellia t errane/metabasalt fields while F igure 4 3C shows the silt plotting towards the CPC shale curve, a collection of Pb isotopic data from galena hosted in shales into which the CPC intruded. Figures 4 3B and 4 3D highlight a smaller range in isotopic ratios to better differentiate trends between bulk and silt samples. Bulk samples in both figures show positive trends between 208 Pb/ 204 Pb, 207 Pb/ 204 Pb and 206 Pb/ 204 Pb, possibly indicating enrichment due to radioactive decay wit hin one source rock region. It is also possible that this trend could represent mixing between different source terranes such as the CPC and Orca/Valdez or the Orca/Valdez with the metabasalts. While the Yakataga samples have different isotopic values betw een the silt and bulk, the modern Bering/Tana glacier samples have much less difference between the silt and bulk. In the silt isotopic ratio analyses, the two groups of Yakataga stratigraphic sections show separation. The samples from the unconformable s ections plot towards one end member with the modern Bering/Tana Glacier sediment samples plotting linearly towards another. The negative (increasing 206 Pb/ 204 Pb; decreasing 207 Pb/ 204 Pb) trend of the silt samples in Figure 4 3D as well as st r onger clusterin g of points along a linear trend as compared to the bulk fraction likely indicates the mixing of different source rocks. Based on the potential source region fields as plotted in Figure 4 3A and 4 3C, it is unclear as to what the end member sources for the silt fraction are, but can be potentially resolved when elemental data are also considered.

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38 Table 4 1. Silt XRD data modern Bering/Tana Glacier samples (07YA08, 07YA09, and 6EUT46), Yakataga samples (section abbreviations in tex t), and Kulthieth/Poul C reek samples. Kulthieth samples 133). Poul Creek samples are indicated by PC after the sample number. An entry of Minor indicates the peak intensity of the m ineral was less than 15% and Trace means the peak intensity was below 3%. Sample Name Quartz Albite Anorthite Microcline Orthoclase Kaolinite Chlorite Biotite Muscovite Potassium Silicate Calcite Siderite Dolomite Cordierite Dickite Tremolite Pyrite Halloysite 6EUT46 91.5 8.5 Trace Minor 07YA08 59.9 31.9 8.1 Trace 07YA09 64 36 CY2 3 58.6 41.4 Minor CY2 15 63.3 36.7 Trace CY2 36 64.8 35.2 Trace CY2 88 93 minor minor 7 Trace CY2 163 49.5 3.4 min or Trace CY2 197 94.4 minor 5.6 CY2 235 63.6 36.4 Minor KI1 102PC 64.2 35.8 Trace KI1 124 64.6 35.4 Minor KI1 138 55.3 39.2 5.5 KI1 166 43.5 22.1 Trace Trace 34.5 KI1 209 52.9 5.8 6.6 Trace KI1 226 50.2 Minor Trace 49.8 KI1 333 59.9 36.2 Minor KI1 351 42.7 54.2 3.1 KI1 368 56.3 5.4 Trace KM1 6 83.5 11.4 5.1 KM1 16 44.1 27.6 Trace SV1 03 56.1 38.1 Trace SV1 024 63.2 33.5 Trace SV1 042 53.8 34.5 Trace Trace SV1 070 67.4 30.1 Trace SV3 089 63.3 36.7 Trace WI1 022 65.2 34.8 Trace WI1 214 92.9 Major Minor 7.1 WI1 224 76.2 Trace Trace Trace WI1 249 100 Trace Trace WI1 262 63.9 14.3 2.8 17.3 WI1 293 67.5 17.9 14.6 Minor Minor WI2 035 63.6 30.7 5.8

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39 Table 4 1 Continued Sample Name Quartz Albite Anorthite Microcline Orthoclase Kaolinite Chlorite Biotite Muscovite Potassium Silicate Calcite Siderite Dolomite Cordierite Dickite Tremolite Pyrite Halloysite Yakutat Ter rane 071505 07YG 51.7 44.9 3.5 CY1 285PC 43.3 51.3 5.5 CY2 156PC 14.8 81.2 Minor WI1 12PC 44.2 30.2 17 Minor 8.6 WI1 103PC 61 39 Minor WI1 173PC 53.9 37.9 8.2 Minor KR1 133Kul 59.8 26.3 6.9 7 KR1 190Kul 71.5 28.5 Minor Minor SK1 21Kul 65.6 16.4 18 SK1 148Kul 80.9 19.1 SK1 180Kul 72.1 26.3

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40 Table 4 2 Bulk elemental da ta for Yakataga and modern Bering/Tana Glacier samples. Data was collected using an E2 Element ICP MS at University of Florida. Sample preparation and analyses are described in Kamenov et al. (2009). Sample Number 07YA09 6EUT46 07YA08 KM1_16 SV1_3 SV1_024 SV1_042 SV3_070 Oxide (%) Na 2 O 3.28 3.26 2.76 2.66 2.51 2.65 2.63 2.45 MgO 2.08 2.14 3.29 3.84 4.87 4.58 4.56 4.04 Al 2 O 3 13.78 14.54 14.25 16.05 15.21 16.21 16.08 15.26 P 2 O 5 0.14 0.26 0.13 0.16 0.18 0.18 0.20 0.17 K 2 O 1.30 1.32 0.75 1.38 1.55 1.63 1.51 1.48 CaO 3.12 4.23 6.53 3.87 4.53 4.31 4.24 3.16 TiO 2 0.75 0.70 0.87 0.95 0.96 0.97 1.00 0.90 MnO 0.07 0.10 0.12 0.11 0.13 0.13 0.13 0.10 Fe 2 O 3 5.50 5.19 7.73 8.22 9.06 8.68 8.94 7.81 LOI% 97.62 98.99 97.44 96.69 96.42 97.55 97.06 96.40 To tal 30.03 31.73 36.43 37.24 38.99 39.33 39.30 35.37 Si Estimate 67.60 67.26 61.01 59.45 57.43 58.21 57.77 61.02 Trace Element (ppm) Li 27.13 24.04 19.33 33.72 41.55 39.32 36.63 40.76 Sc 17.19 18.84 26.79 25.71 27.26 23.82 26.33 23.54 Ti 4420. 29 3889.25 4959.17 5396.12 5863.82 5645.69 5529.08 5679.66 V 126.62 122.82 206.13 200.13 233.47 195.84 217.44 191.96 Cr 89.30 75.47 107.17 130.45 138.59 132.72 131.57 134.44 Co 13.74 12.73 22.27 21.74 29.01 25.51 27.65 23.94 Ni 34.12 29.19 47.78 53.22 64.70 59.49 60.27 58.22 Cu 31.79 37.91 72.79 56.35 74.79 60.50 64.60 66.08 Zn 62.73 64.24 64.49 93.35 113.02 112.64 96.53 94.73 Ga 14.46 15.62 15.60 18.23 18.98 18.79 18.20 18.92 Rb 36.15 43.06 22.20 50.54 53.13 52.61 48.15 50.86 Sr 349.30 352.80 244. 27 263.40 234.14 272.82 240.68 261.51 Y 22.43 32.65 27.51 23.59 23.72 23.28 24.33 24.51 Zr 78.73 47.94 79.47 69.19 64.10 60.23 57.26 59.84 Nb 8.85 9.10 6.43 8.76 9.07 9.31 8.99 9.31 Cs 1.14 1.68 0.76 2.46 2.46 2.31 2.00 2.37 Ba 605.60 675.56 284.95 49 5.88 522.94 580.53 522.75 534.93 La 20.59 33.62 14.25 19.30 13.67 16.16 15.07 16.63 Ce 40.78 66.55 28.84 38.61 28.09 33.15 31.04 34.22 Pr 4.97 7.96 3.61 4.71 3.60 4.16 3.89 4.25 Nd 19.99 31.22 15.19 18.88 14.85 17.34 16.34 17.47 Sm 4.20 6.44 3.62 3.97 3.50 4.04 3.77 3.99 Eu 1.16 1.42 1.17 1.09 0.99 1.15 1.06 1.11 Gd 3.88 6.02 3.85 3.88 3.53 4.07 3.78 4.10 Tb 0.60 0.90 0.66 0.63 0.58 0.66 0.62 0.66 Dy 3.69 5.41 4.31 3.89 3.73 4.00 3.98 4.02 Ho 0.72 1.06 0.88 0.80 0.76 0.82 0.79 0.81 Er 2.15 3.13 2 .66 2.28 2.19 2.37 2.33 2.35 Tm 0.33 0.45 0.40 0.35 0.34 0.36 0.36 0.36 Yb 2.05 2.85 2.53 2.15 2.20 2.25 2.21 2.21 Lu 0.30 0.40 0.38 0.32 0.32 0.33 0.33 0.33 Hf 2.22 1.42 2.11 1.89 1.69 1.79 1.61 1.74 Ta 0.51 0.54 0.36 0.51 0.52 0.57 0.51 0.56 Pb 7.7 3 10.15 5.90 7.87 7.72 8.67 7.64 8.58 Th 4.32 8.92 2.78 4.78 3.57 4.10 3.82 4.38 U 1.57 3.59 1.01 1.58 1.25 1.57 1.26 1.67

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41 Table 4 2 Continued Sample Number CY2_3 CY2_15 WI2_035 WI1_249 KI1_226 KI1_209 Oxide (%) Na 2 O 2.80 2.67 3.14 1.34 2.22 2 .30 MgO 4.05 4.01 3.81 2.84 2.85 2.61 Al 2 O 3 16.00 16.02 17.78 17.75 14.21 13.46 P 2 O 5 0.30 0.20 0.18 0.18 0.22 0.14 K 2 O 2.05 2.20 2.34 2.05 1.80 1.57 CaO 3.38 2.73 2.58 3.19 13.91 8.04 TiO 2 0.92 0.92 0.90 0.87 0.77 0.76 MnO 0.12 0.12 0.10 0.06 0.35 0 .22 Fe 2 O 3 8.33 8.37 8.22 7.18 6.69 5.94 LOI% 96.63 96.29 95.71 90.77 95.24 95.60 Total 37.95 37.23 39.04 35.46 43.01 35.04 Si Estimate 58.67 59.06 56.68 55.31 52.22 60.57 Trace Element (ppm) Li 45.68 53.67 77.97 74.42 44.69 46.24 Sc 22.68 24. 08 20.18 18.96 20.26 18.78 Ti 5660.13 5639.35 5230.14 5086.15 4383.21 4627.90 V 192.55 217.84 175.44 181.01 150.05 147.35 Cr 106.75 112.60 97.89 89.99 84.55 88.36 Co 22.94 24.96 16.08 18.28 13.97 15.98 Ni 46.31 51.26 42.02 41.49 37.18 37.10 Cu 51.40 61.86 49.67 47.95 39.57 37.98 Zn 112.74 126.62 120.07 96.21 87.62 87.21 Ga 19.90 21.05 20.88 20.09 15.81 15.68 Rb 66.58 75.20 72.99 66.37 56.02 54.29 Sr 285.51 255.00 221.18 802.86 248.13 251.06 Y 28.55 26.16 23.97 22.76 29.91 29.62 Zr 89.65 101.17 9 0.01 93.24 81.26 82.11 Nb 11.65 11.98 12.49 10.22 8.82 9.50 Cs 2.82 3.43 3.27 3.37 2.81 2.72 Ba 746.14 734.66 883.99 750.37 638.08 638.99 La 20.62 19.66 21.65 18.86 23.53 22.80 Ce 41.00 40.44 42.66 39.41 42.07 44.51 Pr 5.03 4.95 5.19 4.80 5.04 5.23 Nd 20.74 20.46 20.33 19.57 20.92 21.19 Sm 4.69 4.46 4.41 4.30 4.38 4.48 Eu 1.28 1.24 1.11 1.13 1.25 1.34 Gd 4.71 4.43 4.05 4.06 4.44 4.53 Tb 0.74 0.70 0.63 0.63 0.69 0.71 Dy 4.40 4.38 3.85 3.80 4.18 4.45 Ho 0.91 0.86 0.77 0.75 0.84 0.87 Er 2.59 2.59 2.24 2.16 2.50 2.57 Tm 0.39 0.40 0.35 0.34 0.37 0.39 Yb 2.52 2.44 2.28 2.23 2.33 2.36 Lu 0.38 0.37 0.34 0.32 0.36 0.35 Hf 2.43 2.73 2.38 2.68 2.08 2.15 Ta 0.67 0.66 0.71 0.59 0.51 0.54 Pb 9.52 10.21 9.61 10.56 8.58 8.55 Th 5.31 5.25 6.67 5.36 4.44 4.44 U 2.23 1.96 2.72 3.47 2.06 1.94

PAGE 42

42 Table 4 3 Silt elemental data for Yakataga and modern Bering/Tana Glacier samples. Data was collected using an E2 Element ICP MS at University of Florida. After separation of the silt fraction (15 paration and analyses were performed as described in Kamenov et al. (2009). Sample Number 07YA08 6EUT46 07YA09 SV1_03 SV1_024 SV1_042 SV3_070 SV3_070b Oxide (%) Na 2 O 2.03 3.43 3.59 2.90 2.86 2.86 4.26 4.29 MgO 2.18 2.01 1.99 3.63 3.42 3.18 4.61 4.31 Al 2 O 3 10.19 14.29 13.95 13.58 13.27 13.09 19.35 18.63 P 2 O 5 0.15 0.31 0.24 0.17 0.18 0.17 0.24 0.24 K 2 O 0.43 1.17 1.24 1.27 1.25 1.14 1.73 1.74 CaO 5.47 4.60 3.37 3.57 3.62 3.67 4.61 4.44 TiO 2 0.75 0.64 0.84 0.82 0.80 0.79 1.09 1.15 MnO 0.08 0.08 0.05 0.10 0.10 0.10 0.11 0.12 Fe 2 O 3 5.07 4.01 4.49 7.26 6.57 6.50 8.46 8.70 LOI% 99.07 99.34 98.49 98.07 98.23 97.51 97.42 97.42 Total 26.34 30.53 29.78 33.31 32.09 31.51 44.48 43.63 Si Estimate 72.73 68.81 68.72 64.76 66.14 66.00 52.94 53.79 Trace Element (ppm) Li 10.11 19.43 28.50 31.39 29.25 27.96 43.28 44.39 Sc 23.76 17.80 17.23 21.86 20.98 22.67 29.04 28.79 Ti 4599.65 4128.86 5285.50 5358.37 5188.18 5398.79 7604.70 7792.05 V 172.18 111.49 123.67 184.73 166.92 190.62 229.16 236.31 Cr 99.16 64.89 83.22 108.22 106.89 105.69 154.65 157.33 Co 15.32 10.80 10.11 23.67 21.64 22.85 28.81 28.61 Ni 34.07 24.82 27.40 51.32 46.63 47.23 66.49 64.74 Cu 72.53 34.66 27.77 60.35 57.39 54.61 70.51 67.12 Zn 38.71 55.71 53.79 93.77 84.57 84.26 114.15 115.99 Ga 11.45 15.16 14.73 16.87 15.94 16.89 22.55 25.05 Rb 11.89 34.89 33.30 44.72 42.31 42.98 57.87 58.09 Sr 198.89 376.03 354.39 264.04 286.82 275.44 419.54 409.22 Y 28.03 33.65 24.55 22.06 23.18 25.49 32.14 32.92 Zr 79.33 62.11 98.71 62.28 57.22 55.85 106.07 107.68 Nb 5.80 8.68 10.89 8.16 8.24 8.74 12.11 12.20 Cs 0.40 1.33 1.11 2.01 1.89 1.88 2.65 2.68 Ba 183.40 613.50 578.72 499.64 471.53 485.91 685.56 700.58 La 17.38 34.66 25.73 13.67 17.17 16.19 25.15 24.49 Ce 35.62 69.31 51.55 28.36 35.3 4 32.81 51.24 50.06 Pr 4.48 8.44 6.20 3.61 4.46 4.14 6.30 6.22 Nd 18.76 33.61 24.55 15.17 18.36 17.06 25.92 25.37 Sm 4.36 7.03 5.04 3.56 4.10 3.95 5.75 5.68 Eu 1.15 1.46 1.30 1.02 1.10 1.11 1.56 1.57 Gd 4.60 6.57 4.58 3.57 3.97 4.01 5.64 5.60 Tb 0.79 1.03 0.72 0.62 0.66 0.67 0.94 0.95 Dy 4.85 5.88 4.22 3.71 4.00 4.12 5.59 5.71 Ho 0.98 1.15 0.85 0.78 0.80 0.84 1.14 1.15 Er 2.83 3.22 2.47 2.21 2.28 2.39 3.22 3.28 Tm 0.42 0.47 0.38 0.35 0.35 0.37 0.51 0.50 Yb 2.65 2.94 2.35 2.11 2.17 2.35 3.11 3.13 Lu 0.40 0.42 0.35 0.32 0.32 0.33 0.45 0.46 Hf 2.31 1.84 2.88 1.79 1.63 1.58 3.02 3.05 Ta 0.38 0.58 0.69 0.52 0.52 0.52 0.79 0.78 Pb 4.32 13.75 8.84 45.54 59.67 53.36 56.77 57.13 Th 4.10 10.23 6.16 3.72 4.22 4.27 6.38 6.40 U 1.37 3.02 2.15 1.43 1.41 1 .43 2.46 2.41

PAGE 43

43 Table 4 3 Continued Sample Number SV3_089 SV3_089b WI2_022 WI2_035 WI1_214 WI1_224 WI1_224b WI1_249 Oxide (%) Na 2 O 2.92 2.89 3.22 3.16 2.26 2.11 2.02 1.48 MgO 3.05 3.02 2.05 2.48 1.84 3.49 3.29 2.29 Al 2 O 3 13.28 12.88 13.79 13.9 9 14.85 16.19 15.41 13.77 P 2 O 5 0.16 0.15 0.21 0.19 0.26 0.17 0.16 0.20 K 2 O 1.12 1.08 1.73 1.72 2.08 2.18 2.06 1.72 CaO 3.72 3.64 1.97 2.07 1.28 0.79 0.74 2.65 TiO 2 0.81 0.80 0.61 0.48 0.81 0.78 0.74 0.68 MnO 0.09 0.09 0.05 0.06 0.04 0.08 0.07 0.05 Fe 2 O 3 6.15 6.12 4.81 5.45 5.68 11.64 11.06 6.20 LOI% 98.20 98.20 98.43 97.86 94.60 89.87 89.87 94.00 Total 31.30 30.67 28.44 29.59 29.12 37.41 35.56 29.03 Si Estimate 66.90 67.52 70.00 68.27 65.48 52.46 54.31 64.97 Trace Element (ppm) Li 26.62 27.27 48.90 51.11 60.83 86.68 86.61 55.78 Sc 20.35 20.86 11.52 10.89 15.04 19.89 20.02 15.26 Ti 5390.59 5492.04 4286.70 3328.43 5153.32 4728.47 4758.57 4426.30 V 164.16 167.68 104.10 65.04 142.65 187.89 188.81 148.29 Cr 105.45 105.73 70.50 63.38 75.89 83.16 82.89 73.03 Co 19.24 19.58 9.35 11.21 16.58 16.76 16.93 16.57 Ni 45.77 46.18 24.75 30.04 34.26 43.03 42.91 36.11 Cu 44.76 45.56 35.93 34.46 54.96 51.70 52.39 46.75 Zn 75.44 78.95 90.61 106.91 80.18 149.61 150.76 100.06 Ga 15.96 16.33 15.37 15.19 16.51 16.66 16.78 14.94 Rb 38.27 38.90 57.52 56.95 64.44 70.69 70.38 55.39 Sr 284.30 289.16 272.86 239.06 424.21 173.89 174.11 635.51 Y 22.88 24.08 23.60 16.65 22.79 22.60 22.31 20.65 Zr 55.03 66.32 103.64 42.28 109.96 94.05 101.43 93.71 Nb 8.23 8.41 10.42 8.02 11.07 9.26 9.31 8.79 Cs 1.65 1.67 2.20 2.23 2.64 3.30 3.38 2.53 Ba 451.15 461.78 822.68 834.87 838.65 726.94 722.82 723.12 La 16.88 17.85 26.07 16.49 17.34 16.47 17.06 14.93 Ce 34.59 36.48 52.46 33.31 34.91 33.90 34.84 31.05 Pr 4.33 4.53 6 .25 4.07 4.28 4.12 4.28 3.70 Nd 17.78 18.54 24.40 16.30 17.55 16.89 17.55 15.29 Sm 4.00 4.11 5.04 3.49 3.86 3.65 3.85 3.40 Eu 1.12 1.14 1.16 0.93 1.02 0.98 1.01 0.93 Gd 3.97 4.10 4.59 3.25 3.60 3.56 3.68 3.38 Tb 0.67 0.68 0.71 0.50 0.58 0.61 0.62 0.57 Dy 3.97 4.09 4.10 2.74 3.49 3.72 3.78 3.47 Ho 0.82 0.84 0.82 0.54 0.73 0.78 0.79 0.72 Er 2.32 2.42 2.39 1.52 2.12 2.32 2.32 2.05 Tm 0.35 0.37 0.37 0.24 0.33 0.37 0.37 0.32 Yb 2.16 2.32 2.32 1.47 2.14 2.29 2.33 2.06 Lu 0.31 0.33 0.35 0.21 0.32 0.35 0 .36 0.31 Hf 1.71 1.97 2.94 1.21 3.03 2.61 2.89 2.74 Ta 0.54 0.55 0.67 0.47 0.64 0.56 0.57 0.54 Pb 32.03 32.21 26.94 38.94 63.54 25.99 26.60 85.26 Th 4.29 5.31 7.49 4.99 5.07 5.28 5.36 4.52 U 1.47 1.72 3.02 1.95 3.45 2.33 2.33 3.17

PAGE 44

44 Table 4 3 Continu ed Sample Number WI1_262 CY2_3 CY2_15 CY2_36 CY2_36b CY2_88 CY2_163 CY2_197 Oxide (%) Na 2 O 1.69 3.13 3.11 3.51 2.97 2.98 3.19 3.24 MgO 1.68 3.12 3.15 2.88 2.56 3.76 2.71 2.67 Al 2 O 3 13.94 14.20 14.58 15.03 12.79 13.43 13.68 13.83 P 2 O 5 0.26 0.22 0.19 0.21 0.17 0.19 0.25 0.19 K 2 O 1.94 1.62 1.78 1.64 1.35 1.54 1.63 1.21 CaO 1.46 3.19 2.62 3.29 2.81 3.86 3.38 3.78 TiO 2 0.70 0.79 0.79 0.82 0.67 0.90 0.79 0.73 MnO 0.05 0.09 0.09 0.09 0.07 0.12 0.09 0.09 Fe 2 O 3 6.02 6.59 6.85 6.36 5.33 7.96 5.76 5. 83 LOI% 97.00 98.62 97.27 98.48 98.48 97.85 97.00 98.65 Total 27.74 32.95 33.17 33.82 28.74 34.75 31.46 31.57 Si Estimate 69.26 65.67 64.10 64.66 69.74 63.10 65.54 67.08 Trace Element (ppm) Li 35.80 51.37 33.34 39.07 31.56 30.85 34.52 26.01 Sc 14.16 14.59 17.52 17.75 16.07 15.82 23.31 16.56 Ti 4528.71 4227.29 5123.03 5152.20 4858.88 4806.66 5902.50 5128.19 V 140.52 129.46 153.58 162.97 136.06 132.91 199.06 143.54 Cr 73.67 69.40 82.33 85.16 70.73 68.99 119.67 85.79 Co 13.11 11.50 18.59 19. 40 15.36 15.02 19.90 17.78 Ni 30.18 29.56 37.63 38.39 30.54 30.25 41.76 35.11 Cu 52.42 38.41 41.88 52.78 42.63 42.76 33.33 34.68 Zn 106.75 103.31 103.58 113.50 85.11 82.01 100.54 85.33 Ga 14.66 14.32 17.26 17.49 16.16 16.03 17.79 16.37 Rb 55.28 55.47 52.26 56.03 48.25 47.68 48.72 50.59 Sr 358.88 326.25 308.89 292.86 313.54 315.28 379.50 351.27 Y 19.93 21.17 22.01 22.04 21.66 21.72 24.78 22.26 Zr 98.57 102.57 65.67 79.24 62.89 62.87 59.71 78.14 Nb 9.17 9.19 10.01 10.00 8.96 9.09 10.81 10.10 Cs 2.27 2.18 2.10 2.49 1.72 1.69 1.96 1.87 Ba 831.00 894.41 679.90 653.97 607.58 606.67 684.54 782.90 La 16.92 14.79 17.77 17.20 18.23 18.13 21.09 20.12 Ce 34.30 29.58 35.39 35.28 36.50 36.52 42.35 39.80 Pr 4.22 3.59 4.40 4.37 4.52 4.54 5.19 4.88 Nd 17.35 14 .73 17.97 17.89 18.34 18.34 20.86 19.67 Sm 3.81 3.15 3.98 3.98 4.04 4.03 4.46 4.23 Eu 1.02 0.87 1.14 1.12 1.13 1.14 1.16 1.17 Gd 3.56 3.12 3.85 3.84 3.86 3.91 4.27 4.03 Tb 0.57 0.53 0.63 0.63 0.63 0.64 0.71 0.65 Dy 3.33 3.22 3.73 3.76 3.72 3.77 4.22 3 .84 Ho 0.68 0.68 0.76 0.77 0.75 0.76 0.86 0.77 Er 1.95 1.97 2.15 2.20 2.11 2.17 2.46 2.24 Tm 0.31 0.31 0.33 0.35 0.33 0.33 0.38 0.33 Yb 1.98 1.93 2.11 2.12 1.99 2.01 2.39 2.11 Lu 0.31 0.30 0.31 0.32 0.29 0.30 0.35 0.32 Hf 2.77 2.81 1.88 2.17 1.80 1.8 3 1.80 2.24 Ta 0.56 0.50 0.63 0.61 0.57 0.58 0.66 0.62 Pb 59.07 51.65 42.31 38.39 35.59 35.60 28.15 50.41 Th 4.66 4.42 4.40 4.65 4.63 4.79 5.16 4.81 U 3.53 2.11 1.80 1.78 1.68 1.86 2.10 1.93

PAGE 45

45 Table 4 3 Continued Sample Number CY2_235 CY2_235b KI1_124 KI1_138 KI1_166 KI1_209 KI1_226 KI1_333 Oxide (%) Na 2 O 2.92 3.78 3.71 2.94 2.68 3.01 2.20 3.35 MgO 2.59 3.17 2.33 2.56 2.62 2.81 2.28 2.34 Al 2 O 3 12.26 15.81 14.04 13.99 13.12 14.32 11.94 13.52 P 2 O 5 0.16 0.20 0.21 0.19 0.45 0.22 0.25 0.19 K 2 O 1.05 1.37 1.90 1.80 1.60 1.73 1.44 1.44 CaO 3.28 4.27 1.98 1.99 10.20 2.68 10.03 1.88 TiO 2 0.68 0.91 0.76 0.76 0.69 0.84 0.64 0.71 MnO 0.08 0.10 0.06 0.06 0.26 0.09 0.30 0.05 Fe 2 O 3 5.23 6.83 5.57 5.92 5.90 6.58 5.27 5.56 LOI% 98.41 98.41 98.53 97.09 97.28 96.97 96.04 97.43 Total 28.25 36.44 30.58 30.23 37.51 32.28 34.36 29.04 Si Estimate 70.16 61.97 67.95 66.86 59.77 64.69 61.68 68.38 Trace Element (ppm) Li 24.97 28.72 32.74 43.77 49.60 40.21 53.47 37.39 Sc 17.73 19.97 14.81 14.81 16.13 13.97 14.22 14.95 Ti 4800.48 5130.27 4975.65 4733.65 5139.07 4349.39 5335.63 4278.12 V 139.59 157.37 122.32 121.00 141.95 123.20 144.25 121.07 Cr 72.06 85.35 92.45 75.11 87.92 73.73 87.47 70.23 Co 14.76 16.33 11.08 11.21 12.88 12.82 16.44 12.33 Ni 31. 84 34.92 29.97 27.73 33.81 31.74 37.37 31.28 Cu 39.53 47.84 36.93 31.06 39.43 36.83 42.38 41.38 Zn 72.61 74.99 80.96 81.14 98.51 92.61 107.68 86.88 Ga 15.35 15.76 12.95 15.15 17.66 14.03 16.02 13.72 Rb 38.06 37.97 37.29 53.99 63.66 50.10 57.02 49.88 S r 358.50 336.69 248.34 281.37 267.95 281.87 247.22 259.69 Y 24.16 23.68 25.55 23.36 25.20 26.54 24.20 27.29 Zr 55.72 63.76 74.99 82.95 99.70 83.42 93.80 71.78 Nb 8.27 8.24 9.84 9.55 11.54 9.01 10.89 9.04 Cs 1.40 1.45 1.57 1.92 2.76 2.31 2.61 2.36 Ba 5 30.77 487.61 794.01 943.59 829.72 648.36 796.91 625.32 La 17.95 17.49 22.60 22.29 21.86 23.46 20.12 22.08 Ce 36.02 35.94 44.88 43.86 42.95 41.24 40.48 40.47 Pr 4.52 4.53 5.45 5.34 5.21 4.93 4.98 4.89 Nd 18.49 18.60 21.76 21.08 20.76 19.81 20.29 19.68 Sm 4.10 4.22 4.66 4.42 4.35 4.09 4.36 4.09 Eu 1.14 1.17 1.15 1.15 1.17 1.11 1.17 1.15 Gd 4.05 4.11 4.45 4.19 4.22 4.13 4.19 4.12 Tb 0.66 0.70 0.72 0.69 0.68 0.66 0.68 0.65 Dy 3.86 4.05 4.22 3.97 3.98 3.95 4.01 3.78 Ho 0.79 0.81 0.86 0.81 0.81 0.82 0.8 1 0.79 Er 2.23 2.33 2.44 2.29 2.34 2.34 2.37 2.26 Tm 0.33 0.35 0.38 0.35 0.36 0.35 0.36 0.34 Yb 2.08 2.16 2.36 2.24 2.26 2.22 2.27 2.14 Lu 0.30 0.31 0.35 0.33 0.34 0.33 0.34 0.32 Hf 1.61 1.81 2.17 2.34 2.76 2.15 2.59 1.92 Ta 0.50 0.51 0.60 0.62 0.67 0.57 0.67 0.52 Pb 27.58 26.75 30.87 20.16 36.97 28.53 30.29 48.71 Th 4.69 4.50 6.68 5.48 6.13 4.13 5.39 4.49 U 1.67 1.64 2.43 2.13 2.38 1.80 2.19 1.98

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46 Table 4 3 Continued Sample Number KI1_351 KI1_351b KI1_368 KM1_6 KM1_6b KM1_16 Oxide (%) Na 2 O 3.53 3.88 3.34 4.03 4.05 3.30 MgO 2.56 2.84 2.99 4.27 3.93 3.25 Al 2 O 3 13.91 15.37 15.08 18.94 18.02 14.58 P 2 O 5 0.24 0.27 0.23 0.24 0.22 0.19 K 2 O 1.49 1.67 1.82 1.44 1.44 1.18 CaO 1.76 1.98 1.51 5.59 5.29 4.32 TiO 2 0.68 0.76 0.83 0.99 1.11 0.86 Mn O 0.05 0.06 0.06 0.12 0.13 0.10 Fe 2 O 3 5.63 6.28 6.33 7.95 8.35 6.66 LOI% 97.98 97.98 96.93 97.83 97.83 97.86 Total 29.86 33.09 32.19 43.55 42.53 34.44 Si Estimate 68.12 64.89 64.74 54.28 55.30 63.42 Trace Element (ppm) Li 46.77 47.52 51.10 33. 75 34.99 26.60 Sc 14.08 14.17 14.05 25.80 26.75 22.40 Ti 5092.02 5126.75 5222.78 6724.06 6755.15 5485.85 V 138.16 138.62 141.38 209.49 218.09 178.65 Cr 83.34 84.30 90.16 132.82 136.23 110.04 Co 17.85 17.94 15.29 26.64 27.38 20.63 Ni 35.60 35.92 38.76 56.19 56.67 42.01 Cu 57.26 54.18 41.65 55.96 53.13 47.68 Zn 108.84 111.48 118.86 92.31 95.32 73.69 Ga 16.41 16.87 16.19 19.68 21.60 16.10 Rb 53.93 54.41 57.51 43.76 45.52 36.65 Sr 271.44 272.99 222.13 360.62 358.53 294.61 Y 23.67 23.92 20.30 29.56 3 0.16 24.83 Zr 98.24 97.66 93.44 75.08 75.35 73.10 Nb 10.16 10.41 10.37 10.15 10.68 8.29 Cs 2.29 2.27 2.75 1.68 1.73 1.57 Ba 811.11 803.80 803.36 556.93 582.44 460.42 La 20.95 20.71 16.93 22.79 22.03 17.77 Ce 42.53 42.20 35.31 46.51 45.75 36.96 Pr 5. 24 5.19 4.40 5.69 5.62 4.58 Nd 20.83 20.76 17.82 23.26 23.13 18.75 Sm 4.49 4.45 3.92 5.19 5.18 4.28 Eu 1.17 1.15 1.04 1.45 1.42 1.18 Gd 4.30 4.27 3.67 5.13 5.06 4.15 Tb 0.69 0.70 0.60 0.87 0.85 0.71 Dy 4.13 4.08 3.53 5.11 5.02 4.31 Ho 0.83 0.82 0.72 1.06 1.02 0.88 Er 2.37 2.35 2.05 3.00 2.93 2.52 Tm 0.36 0.36 0.32 0.46 0.44 0.39 Yb 2.32 2.23 2.02 2.82 2.77 2.44 Lu 0.35 0.34 0.30 0.42 0.40 0.36 Hf 2.72 2.67 2.62 2.25 2.21 2.05 Ta 0.64 0.64 0.63 0.67 0.66 0.52 Pb 40.68 40.77 28.44 24.04 24.12 39 .32 Th 5.64 5.62 5.30 5.82 5.66 4.35 U 2.66 2.46 2.17 2.13 2.01 1.65

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47 Table 4 4 Silt elemental data for Kulthieth and Poul Creek Formation silt samples. Data was collected using an E2 Element ICP MS at University of Florida. After separation of the si lt fraction (15 analyses were performed as described in Kamenov et al. (2009). Sample Number 071505_07 KR1_133 KR1_190 SK1_21 SK1_148 SK1_180 CY2_156 Unit Yakutat Kulthieth Kulthieth Kulthieth Kulthieth Kulthieth Poul Creek Oxide (%) Na 2 O 3.32 2.48 3.16 0.75 0.36 0.42 2.93 MgO 2.35 1.83 2.12 1.15 0.73 0.75 4.91 Al 2 O 3 14.03 19.25 19.66 20.86 16.40 25.64 15.50 P 2 O 5 0.13 0.16 0.11 0.11 0.03 0.08 0.49 K 2 O 1.34 2.95 2.27 1.28 1.74 1.38 1.74 CaO 2.67 0.24 0.49 0.09 0.0 2 0.02 6.03 TiO 2 0.73 0.91 1.23 0.87 0.64 0.96 1.27 MnO 0.09 0.05 0.07 0.13 0.02 0.03 0.16 Fe 2 O 3 5.48 5.54 5.48 6.37 2.77 3.82 12.08 LOI% 98.01 94.09 78.74 77.31 95.52 88.08 97.51 Total 30.13 33.41 34.60 31.62 22.72 33.09 45.10 Si Estimate 67.88 60. 68 44.14 45.68 72.80 54.99 52.41 Trace Element (ppm) Li 28.90 33.06 43.94 49.90 36.86 90.99 42.58 Sc 15.99 20.16 24.71 19.23 11.35 17.13 32.42 Ti 4582.38 5651.97 7468.46 5402.47 3677.14 6300.11 7663.39 V 135.74 178.19 325.15 201.37 92.05 144.29 207.18 Cr 79.27 90.47 103.21 71.07 61.08 70.03 147.38 Co 20.76 13.24 24.95 78.42 8.77 36.50 20.25 Ni 35.05 33.65 34.58 56.12 24.72 31.23 33.90 Cu 42.14 57.66 162.33 127.15 44.98 88.88 33.24 Zn 75.08 107.17 132.57 817.72 119.63 85.91 145.57 Ga 16.26 27.04 24.54 25.09 18.52 35.81 20.91 Rb 48.03 81.55 69.60 62.84 61.45 64.46 46.72 Sr 321.56 113.02 187.31 58.34 48.28 57.40 401.68 Y 18.87 22.77 33.80 29.99 22.09 16.93 35.84 Zr 61.86 133.47 236.40 123.45 88.13 95.36 66.22 Nb 8.57 12.20 12.87 12.71 10. 66 15.00 15.84 Cs 2.48 5.34 4.35 3.90 2.52 4.48 1.70 Ba 605.95 946.52 1191.84 592.08 584.60 1677.82 517.70 La 16.27 21.32 19.44 37.66 34.35 18.13 41.28 Ce 33.45 41.55 40.15 82.84 69.17 37.94 82.50 Pr 3.92 5.18 5.00 9.86 8.22 4.25 9.57 Nd 15.78 20.32 20.97 40.29 32.30 16.53 37.67 Sm 3.50 4.10 5.08 8.33 6.24 3.60 7.56 Eu 1.05 1.04 1.52 2.08 1.39 1.07 1.75 Gd 3.42 3.53 5.68 7.20 5.39 3.32 6.75 Tb 0.55 0.56 0.96 1.03 0.76 0.51 0.99 Dy 3.23 3.49 5.83 5.80 4.15 2.91 5.95 Ho 0.66 0.71 1.17 1.04 0.73 0. 59 1.14 Er 1.89 2.13 3.43 2.88 2.00 1.70 3.31 Tm 0.30 0.35 0.51 0.42 0.30 0.27 0.49 Yb 1.84 2.24 3.28 2.64 1.91 1.75 3.04 Lu 0.27 0.35 0.49 0.38 0.28 0.26 0.44 Hf 1.79 3.23 4.46 2.95 2.64 2.84 1.93 Ta 0.53 0.67 0.69 0.74 0.62 0.95 0.79 Pb 24.96 45.7 3 80.71 77.29 12.07 52.58 34.17 Th 4.10 5.63 6.00 7.90 7.14 9.60 8.40 U 1.49 2.32 3.05 2.47 2.30 3.12 2.84

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48 Table 4 4 Continued Sample Number CY1_285 WI1_12 WI1_103 WI1_173 KI1_102 KI1_102b Unit Poul Creek Poul Creek Poul Creek Poul Creek Poul Creek P oul Creek Oxide (%) Na 2 O 3.08 3.21 3.38 3.72 3.27 3.29 MgO 3.39 3.35 2.97 2.22 2.55 2.59 Al 2 O 3 14.66 17.55 18.29 14.99 13.84 13.95 P 2 O 5 0.22 0.22 0.19 0.29 0.23 0.24 K 2 O 2.03 2.30 2.38 1.79 1.37 1.40 CaO 3.22 0.69 0.72 1.17 2.95 3.00 TiO 2 0.8 4 0.89 0.93 0.80 0.93 0.94 MnO 0.10 0.07 0.07 0.06 0.08 0.08 Fe 2 O 3 6.77 9.78 7.74 5.73 6.36 6.34 LOI% 97.97 95.71 96.54 97.18 98.70 98.70 Total 34.31 38.07 36.67 30.77 31.59 31.83 Si Estimate 63.66 57.64 59.86 66.41 67.11 66.88 Trace Element (ppm) Li 44.38 76.47 72.75 52.68 28.83 32.52 Sc 17.07 18.09 17.26 13.96 19.99 14.56 Ti 5321.13 5150.55 5421.10 4832.69 5183.26 4800.62 V 161.88 183.77 162.81 128.16 158.77 119.89 Cr 92.15 91.66 91.97 78.49 86.94 84.12 Co 15.23 16.43 15.58 12.64 16.51 10.85 Ni 35.35 47.58 37.83 32.51 35.10 29.06 Cu 27.94 56.77 51.96 38.72 47.97 33.22 Zn 106.80 135.33 136.18 88.05 76.26 78.23 Ga 19.68 22.97 21.48 16.42 15.94 13.23 Rb 64.47 72.88 72.04 54.84 38.64 36.96 Sr 382.48 188.17 185.95 267.78 341.02 239.22 Y 21.35 26.88 23.15 24.60 23.76 24.87 Zr 53.17 98.50 103.08 92.08 70.73 103.81 Nb 11.75 10.62 11.41 10.93 8.38 9.47 Cs 2.31 4.04 3.35 2.13 1.48 1.57 Ba 945.65 741.38 750.92 779.57 497.59 789.71 La 18.69 22.68 25.63 25.08 17.84 23.54 Ce 37.46 48.15 51 .37 51.10 36.70 47.51 Pr 4.61 5.66 6.11 6.18 4.64 5.71 Nd 18.86 23.15 23.85 24.54 19.09 22.59 Sm 4.12 5.09 4.77 4.98 4.32 4.69 Eu 1.17 1.38 1.19 1.29 1.20 1.15 Gd 3.87 4.77 4.35 4.67 4.23 4.41 Tb 0.60 0.75 0.67 0.70 0.69 0.71 Dy 3.49 4.55 3.98 4.19 4.09 4.11 Ho 0.69 0.90 0.79 0.81 0.82 0.83 Er 1.95 2.59 2.28 2.36 2.34 2.38 Tm 0.30 0.39 0.35 0.36 0.36 0.36 Yb 1.88 2.43 2.30 2.24 2.18 2.28 Lu 0.27 0.35 0.34 0.34 0.32 0.34 Hf 1.55 2.62 2.91 2.66 1.99 2.88 Ta 0.63 0.58 0.66 0.62 0.53 0.58 Pb 16.9 1 28.39 20.77 17.67 27.01 31.10 Th 4.33 4.81 5.96 5.93 4.43 6.83 U 1.73 2.08 2.41 2.43 1.68 2.56

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49 Table 4 5 Bulk Pb isotopic data for Yakataga and modern Bering/Tana Glacier samples. Data was collected using a Nu ICP MS at University of Florida. Sampl e preparation and analyses are described in Kamenov et al. (2009). Sample 208/204 error 207/204 error 206/204 error SV1 3 38.7244 1.45E 03 15.62245 5.19E 04 19.13475 6.29E 04 CY2 3 38.65988 2.74E 03 15.6189 1.06E 03 19.1794 1.26E 03 07YA08 38.72727 2.92 E 03 15.61245 1.13E 03 19.11507 1.38E 03 SV3 070 38.75181 1.85E 03 15.62386 6.90E 04 19.14713 7.91E 04 KM1 16 38.76056 2.60E 03 15.62477 9.67E 04 19.16134 1.14E 03 6EUT46 38.83532 1.76E 03 15.63626 7.32E 04 19.23152 8.30E 04 07YA09 38.76867 2.93E 03 15 .62649 1.02E 03 19.14516 1.10E 03 SV1 024 38.72351 2.44E 03 15.62461 9.07E 04 19.15877 9.92E 04 SV1 042 38.7486 1.72E 03 15.62396 6.31E 04 19.14359 7.09E 04 WI2 035 38.78351 2.19E 03 15.63293 8.64E 04 19.19504 1.01E 03 WI1 249 38.65115 1.95E 03 15.6182 8.07E 04 19.1462 9.09E 04 CY2 15 38.61175 2.02E 03 15.61368 7.45E 04 19.15832 8.45E 04 KI1 226 38.72433 1.89E 03 15.62575 7.14E 04 19.17489 7.96E 04 KI1 209 38.70567 2.86E 03 15.62433 1.03E 03 19.18239 1.25E 03

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50 Table 4 6 Silt Pb isotopic data for Y akataga and modern Bering/Tana Glacier samples. Data was collected using a Nu ICP MS at University of Florida. After separation of the silt fraction (15 6 were performed as described in Kamenov et al. (2009). Sample 208/204 error 207/204 error 206/204 error SV1 03 38.56494 2.17E 03 15.66344 8.72E 04 19.0389 1.01E 03 SV1 024 38.54471 2.39E 03 15.66749 8.61E 04 19.00874 9.37E 04 SV1 042 38.56679 1.94E 03 15.66947 7.53E 04 19.02763 9.11E 04 KM1 16 38.55773 2.27E 03 15.66226 9.14E 04 19.01377 8.96E 04 07YA08 38.83678 2.19E 03 15.62693 9.05E 04 19.22257 1.14E 03 07YA09 38.88557 2.20E 03 15.63649 8.63E 04 19.21771 9.08E 0 4 6EUT46 38.82879 2.35E 03 15.63188 9.61E 04 19.19221 1.15E 03 CY2 3 38.56717 1.93E 03 15.66008 6.69E 04 19.05202 7.30E 04 CY2 15 38.56477 2.27E 03 15.65938 8.85E 04 19.05497 9.95E 04 WI1 249 38.54433 2.41E 03 15.66739 9.89E 04 19.02781 1.22E 03 WI2 0 22 38.67061 2.76E 03 15.65171 1.03E 03 19.11199 1.13E 03 WI2 035 38.59341 1.87E 03 15.66231 6.89E 04 19.04785 7.81E 04 KI1 124 38.6359 1.72E 03 15.64794 6.54E 04 19.09516 7.70E 04 CY2 88 38.60956 1.59E 03 15.65283 5.79E 04 19.09749 6.86E 04 KI1 333 38. 64457 1.99E 03 15.65443 7.69E 04 19.11764 8.69E 04 CY2 163 38.56989 3.86E 03 15.66366 1.45E 03 19.04996 1.88E 03 CY2 197 38.61716 1.70E 03 15.6569 6.28E 04 19.07527 6.02E 04 KI1 166 38.59581 1.82E 03 15.65689 7.13E 04 19.06734 8.12E 04 KI1 226 38.56634 2.62E 03 15.66462 1.15E 03 19.04572 1.37E 03 KI1 351 38.59898 2.10E 03 15.65656 8.09E 04 19.05874 8.43E 04

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51 Figure 4 1. SEM images and binocular microscope photographs of dissagregated Yakataga silt samples. A. SEM image of KM1 16 Yakataga silt. Mi nerals identified by XRD analyses can be identified in the image and are annotated (chlorite is assumed to be represented in the lithic fragments). B. SEM image of WI2 035 Yakataga silt. Minerals identified are those also observed via XRD. C. Binocular mic roscope photograph of Yakataga silt from sample WI2 035. Very little clay is seen and is assumed to be brown coating on some grains. Quartz and albite can be identified along with ferromagnesian minerals (amphibole/pyroxene) that were not observed by XRD a nalyses. D. Binocular microscope photograph of Yakataga silt from sample SV1 042. Ferromagnesian minerals also can be identified in this image. These images demonstrate that the disaggregation technique of this indurated mudrock successfully separated silt sized grains with minimal incorporation of clay sized material.

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52 Figure 4 2. Yakataga elemental geochemistry spider diagrams. A D are normalized to Mid Ocean Ridge Basalt ( MORB ) ( ). E & F show the bulk fraction normalized to th e silt fraction of the same sample. Colors correspond to the relative lithostratigraphic sections in Figures 1 1B and 1 2. The black lines represent the modern Bering Glacier samples. The dashed purple and aqua lines represent the average elemental values of the Poul Creek and Kulthieth formation silt respectively (A D). The dashed red line (A D) represents the average continental arc trace element signature (Rudnick and Fountain 1995). A. Analyses of the bulk fraction of the Yakataga samples showing a stan dard suite of trace elements (Kamenov et al 2009) B. Bulk sample fraction trace elements unaltered during weathering in the. C. Analyses of the silt size fraction (15 same elements measured in the bulk analyses. D. Silt size fraction unaltered trace element values. E. Bulk fraction sam ple elemental values divided by the corresponding silt fraction values. Most elements plot close to 1 (no enrichment) with the most notable exception being Pb, which is enriched in the silt size fraction. F. Bulk fraction divided by silt fraction of the un altered elements, which are nearly the same between the two fractions. All panels demonstrate a difference in elemental abundances between the different lithostratigraphic sections, including those within the Yakataga.

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53 Figure 4 3. Pb isotopic data. Pa nels A and C show wider range in values and contain fields for some possible source rocks. Fields are corrected to modern values from whole rock analyses from Farmer et al. (1993) and references therein. The Yukon Tanana terrane is located inboard the WCT of Figure 1 1A. Panels B and D show a smaller range in values, with relative locations shown in panels A and C. Symbol colors reflect lithostratigraphic samples (See Figures 1 1 and 1 2). Closed symbols represent silt fraction analyses and open symbols rep resent bulk sample analyses. A. 208Pb/204Pb versus 206Pb/204Pb of all samples analyzed in this study with fields of possible source regions. Box shows location of data in panel B B. 208Pb/204Pb versus 206P b/204Pb of data from our study. C. 207Pb/204Pb vers us 206Pb/204Pb of possible source regions along with data of this study Box in panel C sho ws location of data in panel D Data in panels A and C indicate the bulk reflects a Coast Plutonic Complex (CPC) or Orca/Valdez influence whereas silt fraction sample s shows a different mixture of potentially Wrangellia/Metabasalts or shales of the CPC. D. 207Pb/204Pb versus 206Pb/204Pb of data from our study. Negative trend of silt data indicates mixing of sources while positive trend in bulk data indicates enrichment by decay of single source. All isotopic ratios show that the different stratigraphic sections of the Yakataga have different provenance seen in both the bulk and silt fractions while the modern samples show similar provenance between bulk and silt fractio ns. In panels B and D, the arrow indicates the region of values that the non silt fraction (assumed clay size) must contain to result in bulk fraction measured values.

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54 CHAPTER 5 DISCUSSION Establishing Mudrock Provenance Establishing mudrock sediment pro venance using elemental and isotopic data requires that there is minimal variability in factors other than sediment source in controlling the resulting composition. Weathering and preferential mineral concentration during transport are two important compli cating influences (Bhatia and Crook 1986; Nesbitt et al. 1996). As the likely sediment sources to the Yakataga Formation represent a range of rock types, from fine grain sedimentary (Kulthtieth, Poul Creek, Orca/Valdez Group), metamorphic (CMC), to crystal line (Wrangellia mafics, Saranak Baranof), traditional measures of the degree of weathering (e.g., chemical index of alteration) (Nesbitt et al. 1996) are not likely to provide a clear indication of the influence of weathering on elemental composition beca use the potential sources likely have experience d a wide range of chemical weathering conditions Differential sorting based on particle size and mineralogy during transport from source to sink may also bias elemental and isotopic results. Consequently, I employ a combination of mineralogical, elemental, and isotopic analyses on one size fraction (sortable silt) to better isolate sources of fine grain material in the Yakataga Formation. The consistency of the XRD mineralogy data between samples implies tha t variations in the elemental and isotopic data are controlled predominantly by source rock composition rather than other factors that could affect mineralogy of sediments, including physical sorting. Most Yakataga silt samples contain the predominant mine ral phases quartz, albite, and chlorite. It is likely that the silt trace element variation is predominantly influenced by albite with the chlorite being mostly a trace or minor

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55 influence. Amphibole or other ferromagnesian minerals seen with a binocular mi croscope could also have an effect on trace element variation ( Figure 4 1 ). The low abundances of clay minerals in the silt XRD and visual analyses are reinforced by the elemental data showing low concentrations of K and Rb in the silt fraction commonly a ssociated with the clay fraction of sediments (Dinelli et al. 2007). These elements are both slightly enriched in samples of the bulk fraction relative to the silt fraction ( Figure 4 2 E), indicative of higher clay content in bulk samples. Elemental result s ( Figure 4 2 ) show similar variation compared to MORB in both the bulk rock and silt fractions of the Yakataga. Separation of the different stratigraphic groups is also apparent in elemental data. In subsequent discussion of elemental results, I will focu s on the HFSE (e.g., Zr, Cr, Ce; Fig ure s. 4 3 B, D, F), which more accurately reflect original geochemistry of source rocks (Barbera et al. 2009). Additional justification for their use is noted when the concentrations in the bulk relative to silt fractions are compared (Figures 4 3 E and 4 3 F). In Figure 4 3 E, the two stratigraphic groups show systematic trends in most elements, with the conformable section bulk samples being more elementally enriched versus silt compared to the unconformable section samples This implies that these elements are affected by consistent grain size or mineralogical differences between the two groups of sections that may not actually reflect differences in provenance. The difference between stratigraphic groups in Figure 4 3 E con trasts with the overall consistency of elements between the two size fractions of the two stratigraphic groups in Figure 4 3 F, with only separation seen between stratigraphic sections is in Zr, Y, La, and Ce with the other elements (Nb, Ti, Co, Cr, Ni) sho wing almost no relative enrichment between size fractions. Variation in

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56 concentrations of Ti, Co, Cr, and Ni between stratigraphic sections ( Figure 4 3 B and 4 3 D) is more likely due to provenance differences and not overall grain size or mineralogical diff erences. Grain size and mineralogy could still have an effect on the elemental concentrations within the bulk sample fractions. Bulk samples are more likely to contain sand, which may include zircon and thus be more enriched in Zr. The REE elements Y, La, and Ce also are enriched in the bulk versus silt fractions ( Figure 4 3 E and 4 3 F). Y, La, and Ce also can be controlled by zircon content and should be expected to co vary with Zr if zircon is present. It follows then that the presence of higher Zr, La, Y, and Ce in the bulk versus silt for the conformable section samples indicates that these sections have more zircon. Enrichment in these elements has also been shown to represent increased proportions of recycled sedimentary detritus (Bhatia and Crook 1986) Multivariate Data Analysis To interpret the elemental data I perform principal components analysis on three different data sets. The first data set used in the PCA is a compilation of data representing possible source rocks: the Kulthieth/Poul Creek Form ation silt elemental concentrations from this study (Table 4 4), a metabasite belt within the Chugach Metamorphic complex (CMC) (represen ting a general mafic endmember), plutons of the Sanak Baranoff belt intruded into the CMC (representing a generally fel sic endmember) (Table A1 2), and the Orca and Valdez Groups of the Chugach/Prince William Terrane (Barker et al. 1992; Bruand et al. 2011; Sisson et al. 2003) (Table A1 3). All of the unaltered elements presented in the data sets from this study ( Figure 4 3 B, 4 3 D, and 4 3 F) are not available for all the source data, so only elements that are available for all sources are used in the PCA. Principal Component (PC) 1 explains the majority of the

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57 variance (57%) and is predominantly controlled by the covariance of Y, Cr, and Ni opposite that of Nb, La, and Ce ( Figure 5 1 A). PC 2 controls a smaller proportion of the variance (36%) and is in fluenced primarily by Ti ( Figure 5 1B). Figure 5 1 C shows the samples plotted in principal component space, revealing that Y, Cr, and Ni are strongly associated with the CMC metabasite (mafic) while Nb, La, and Ce are associated with the felsic rocks (Sanak Baranoff plutonics). The sedimentary rocks plot as generally one indistinct group in between these two groups, with a n over all tendency to plot towards the felsic end member. PC 2 varies the most between crystalline and sedimentary rocks, with more scatter in the crystalline sourced samples. It also shows that the sedimentary rocks have a higher influence from Ti (more negativ e loading values) than the majority of the crystalline rocks, suggesting the preferential accumulation of Ti bearing ferromagnesian minerals in the sedimentary rocks (Brenan et al. 1995; McKenzie and Onions 1991; Sisson 1994). The second PCA was performed using the Yakataga bulk sample elemental and Pb isotopic ( 206 Pb/ 204 Pb) data to attempt to explain the mineralogical controls on Pb isotopic values. In this PCA, the first 3 principle components explain over 90% of the data var iance ( Figure 5 2A C). PC 1 ( F igure 5 2 A) is similar to PC 1 for the source rock data ( Figure 6A), showing the difference between elements associated with mafic rocks (Cr, Co, Ni) versus those associated with felsic rocks (Ce, La). In this PCA, Y trends instead with the felsic elements while Ti trends strongly with the mafic elements. PC 2 ( Figure 5 2 B) is controlled strongly by Nb and Zr and likely represents a grain size effect, as samples with minimal PC 2 loadings would be lacking in zircon. The PCA also helps interpret the bulk Pb isotopic data with higher 206 Pb/ 204 Pb isotopic ratios

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58 correlating with the felsic associated elements. In PC 1 versus PC 2 principal component space of the bulk Yakataga samples ( Figure 5 2 D), the two stratigraphic groups separate into two general clusters More of this variation is on PC 1 but variation is present on PC 2 as well (note larger scale on PC 1 axis). Samples from the unconformable Yakataga sections have more of a mafic source component being more negative in PC 1 (Cr, Ni, and Y). Samples from the conformable sections are positive in PC 1 (high in Nb and Ce) and thus have a more felsic influence. In PC 2, the conformable sections are more positive indicating increased Nb and Zr, suggesting that these bulk rock samples contain more zircon. Zr in the bulk samples of the conformable sections is more enriched relative to silt than th e unconformable sections ( Figure 4 2 F). This could either indicate these conformable section samples are coarser grained, have more of a felsic source rock, or have more of a recycled sedimentary rock source material (Bhatia and Crook 1986). Modern Bering/Tana glacier samples are highly variable in the bulk PCA. On both PC 1 and PC 2 the modern samples show a similar amount of variation as all of the Yakataga samples, eve n though there are only 3 modern samples. With these samples coming directly from glacial outwash, their wide variation reflects the differences in grain size and/or bedrock composition that the glaciers they are sourced from override. (6EUT46 from the San ak Baranoff and CMC and 07YA08 & 07YA09 coming from Kulthieth/Poul Creek ; Headley et al. 2013 ). The third PCA was performed on data from just the Yakataga silt size fraction and includes both elemental and Pb isot opic data ( 206 Pb/ 204 Pb) (Fig ures 5 3 A and 5 3 B). Only the 206 Pb/ 204 Pb ratio was used in the PCA because of strong linear correlations between all Pb isotopic ratios. Because the Pb isotope analyses were

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59 performed on a reduced number of samples, not all of the Yakataga silt samples used for elementa l analysis could be included in the PCA. This PCA is best described using the first 2 principle components, which explain over 70% of the data variance. The elements that are partitioned into the two principal component loadings are nearly identical to tho se for the source rocks ( Figure 5 1 ). Unlike in the bulk sample PCA ( Figure 5 2 ), elemental variability due to grain size of the samples should be not as important of a factor here because all the samples are 15 the minimal influence of Zr on the PC loadings. As with the bulk samples, increasing 206 Pb/ 204 Pb isotopic ratios for the silt values are correlated with felsic elements and lower 206 Pb/ 204 Pb ratios are correlated with mafic elements. Figure 5 3 C shows the samples plotted in PC1 PC2 principal component space, and again, the two Yakataga sample groups (conformable versus unconformable) s eparate mainly based on PC 1. The silts in the conformable sections are more associated with felsic elements while the silts in the unconformable sections are associated with more mafic elements. The modern Bering glacier samples are more closely associate d with the conformable sections indicating they have similar provenance. This is strongly seen in the samples from Bering Glacier outwash, which is sourced directly from Kulthieth/Poul Creek. The Tana Glacier outwash sample likely displays some influence f rom the CMC making it plot nearer to the unconformable samples. Variation of the Yakataga silt samples on PC 2 loadings is minimal with the exception of one conformable sample that is quite low in Ti (WI2 035) that has a strong influence on the resultant l oading values. When compared with global Pb isotopic reservoirs, my data show limited variability and plot entirely within the range for Upper Continental Crust (UCC)

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60 (Rollinson 1993). The PCA can assist in interpreting what the UCC rock type is and shows 206 Pb/ 204 Pb correlating with the felsic associated elements (Ce, La, Y). While not used in the PCA, the fact that 207 Pb/ 204 Pb ratios are negatively correlated with 206 Pb/ 204 Pb isotopic ratios indicates that the 207 Pb/ 204 Pb ratio would be more strongly asso ciated with mafic elements if included ( Figure 4 3 D). Figure 4 3 D also shows that the higher 206 Pb/ 204 Pb values (>19.05) are associated with more felsic sourced samples associated with the conformable sections. This felsic source could be either first cycl e erosion from the Sanak Baranoff plutons or recycling from the CPC via the Kultheith/Poul Creek formations. Given the limited areal exent of the Sanak Baranoff plutons and larger area for the Kultheith/Poul Creek, the later explanation is preferred. The i ncreasing 207 Pb/ 204 Pb ratio may imply an increasing input of mafic sourced material, possibly from the exhuming CMC or unmetamorphosed mafic rocks of the Orca/Valdez Groups. Bulk Fraction Silt Fraction Comparison There are notable differences in the elem ental and isotopic geochemistry between silt and bulk rock fractions of the same samples. The conformable and unconformable stratigraphic samples can be differentiated based on the bulk rock to silt ratios for some of the elements including U, Th, K, Zr, a nd REE and in the pri nciple component analyses (Figures 4 2 E and 5 2 B, 5 3 C and 5 4 D), indicating that the bulk sediment in these conformable sections is consistently more enriched in these elements relative to the silt fraction. Additionally, when the sil t only elemental concentrations relative to MORB are considered ( Figure 4 2 C), little separation exists among the stratigraphic section groups based on U, Th, K, Zr, and REE. This indicates the majority of difference in these elemental concentrations exist s in the non silt fraction, most likely

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61 zircon in the sand fraction or mica/illite in the clay fraction (Bhatia and Crook 1986). This shows that these bulk rock elemental concentrations are more strongly influenced by minerals associated with particular si ze fractions. To reduce this grain size control on mineralogy and resulting elemental concentrations, I just use the silt fraction and only those elements (e.g., Cr, Ni, Ce; Dinelli et al. 2007) that are least likely to be altered by weathering or partitio ned into particular grain sizes in further examination of Yakataga mudrock provenance. Perhaps the most striking difference between the bulk rock and silt fraction is with Pb ( Figure 4 2 E). In nearly all Yakataga samples, the silt contains nearly an order of magnitude more Pb by mass than the bulk material. This excess abundance is not seen in any other elements including transition metals. Because the silt is also contained within the bulk sample, the material that makes up the rest of the bulk sample mus t have a correspondingly low Pb content. As noted previously, I assume the majority of the non silt size minerals in the sample are clays based on a visual inspection (i.e., samples were mudrocks not sandstones). Through a simple mass balance calculation ( Equation 5 1 ), I can calculate the maximum amount of silt sized material present in each sample with silt and bulk rock analyses. Pb silt % silt maximum +Pb non silt % non silt =Pb bulk (5 1) To solve for the maximum concentration of silt sized material present, the Pb concentrations for bulk and silt material respectively are used. To solve for maximum silt concentration, the non silt fraction can be assumed to have 0 ppm Pb, and the resulting calculation reveals that 12 27% of Yakataga bulk rock samples could b e silt size material. However, none of potential sediment sources that have reported elemental

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62 data and are used in this study have 0 ppm Pb in any sample (Bruand et al. 2011; Kamenov et al. 2009; Lamaskin et al. 2008; Sisson et al. 2003). Consequently, th e estimated silt percentage is a maximum and the actual silt percentage must be lower in our samples if the end member contains some Pb. An explanation for the Pb enrichment in the silt fraction is likely due to it being carried in the feldspars where it can substitute for K and Ca in the plagioclase present or the minor amphibole and ferromagnesian minerals seen in visual analyses (Bhatia and Crook 1986). Partition coefficients indicate that of these two possibilities, the plagioclase is the most likely P b carrier (Ewart and Griffin 1994; Kravchuk et al. 1981) with amphibole having low partition coefficients for Pb (Brenan et al. 1995; McKenzie and Onions 1991). Biplots of Yakataga silt elemental concentrations characteristic of common minor mineral phases (e.g., P in apatite and monazite, Ce and Y in monazite, and Zr in zircon) versus Pb show no correlation and indicate that the carrier of Pb is most likely the albite (Rollinson 1993). Pb concentrations of the Yakataga and Yakutat silt samples are higher t han any of the Pb values reported in the potential source rock studies cited in this paper, so I cannot rule out entirely the possibility of post depositional diagenetic enrichment of Pb in the silt. The exact cause of the diagenetic alteration cannot be d etermined with the data of this study but could be due to fluid flow related to deformational and subduction zone processes (Kessel et al. 2005; Kogiso et al. 1997). The Kulthieth/Poul Creek silt samples also show enrichment in Pb, particularly in the Kult hieth formation. To test for sulfide coatings on grains I treated several silt samples separately with 7N nitric acid and 6N hydrochloric acid. The nitric acid test did not indicate the presence of sulfides. Samples slowly reacted with hydrochloric acid

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63 le aving a slightly yellow solution, indicating a source of iron in the samples, possibly small amounts of siderite as seen in the XRD analyses for some of the Yakataga samples (Table 4 1 ). It is unusual that no other transition metals ( e.g Zn, Cu) are as en riched in the silt fraction or show correlation with Pb, which one would expect if fluid alteration was responsible for the high Pb concentrations. Lead Isotopes There are notable differences between bulk rock and silt size Pb isotopic values within the Ya kataga samples, which has important implications for both the provenance of the Yakataga Formation and for studies employing isotopic analyses of fine grained sediments. The difference between the two size fractions is most obvious between 207 Pb/ 204 Pb and 206 Pb/ 204 Pb ( Figure 4 3 D). The bulk rock samples show a positive slope between the two isotopic ratios, which would be expected for a single parent isotopic source that undergoes isotopic enrichment solely due to radioactive decay (Aleinikoff et al. 1987; Farmer et al. 1993; Godwin and Sinclair 1982). The positive trend between isotope ratios in the bulk rock is in stark contrast to the negative slope seen in the silt fraction 207 Pb/ 204 Pb versus 206 Pb/ 204 Pb isotopic data ( Figure 4 3 D). The negative trend in the data indicates a mixing of two sources, one with a higher 207 Pb/ 204 Pb ratio with a second with a higher 206 Pb/ 204 Pb ratio. The unconformable samples are lower in 206 Pb/ 204 Pb but higher in 207 Pb/ 204 Pb than the conformable samples, and the modern Bering glacier samples plotting with even higher 206 Pb/ 204 Pb values comparable to those of the bulk rock samples. When looking closer at just the bulk samples a similar pattern is seen, with the unconformable bulk rock samples having elevated 207 Pb/ 204 Pb values over the conformable sections, although the pattern seen in the bulk samples is much less pronounced between the unconformable and conformable sections than in the silt

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64 only analyses. The isotopic difference between silt and bulk could be explained by the greater presence of zircon in the bulk r ock indicated by the PCA ( Figure 5 2B and 5 2 C). However, I do not believe this to be the case because zircon would have a more radiogenic signature with higher 207 Pb/ 204 Pb and 206 Pb/ 204 Pb. This is not seen in Figure 4 3 C where the silt actually has a higher 207 Pb/ 204 Pb than the bulk fraction. I conclude the difference between the bulk rock and silt Pb isotopic composition combined with the large difference in the Pb concentration between the two fractions reflects a difference in provenance between the silt and non silt (assumed to be predominantly clay sized material) size fractions. I cannot rule out the possibility that diagenesis preferentially affected the silt fraction in depositing Pb but previous studies show that the clay fraction contains minerals that are most affected by diagenesis (Bhatia and Crook 1986; Dinelli et al. 2007). The greater isotopic ratio discrimination within the silt provenance relative to the bulk provides strong justification for separati ng and analyzing the silt size fraction when using Pb isotopes for provenance studies. Our results are consistent with those of Clift et al. (2008) who showed that bulk sediment Pb isotopic ratios have limited provenance applications when compared to isoto pes of specific size fractions (sand in their case) or mineral phases. Previous studies have shown differences in Nd and Sr isotopic ratios between size fractions (Feng et al. 2009; Innocent et al. 2000), but Pb isotopic differences between size fractions have not been previously demonstrated explicitly. Feng et al. (2009) examined Sr and Nd isotopic differences in grain size fractions of aeolian dust, finding that Sr shows more variation with grain size than Nd due to the behavior of Rb and Sr in crystal s ubstitutions. With Nd isotopes they observed increases in model ages

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65 with grain size. In their analysis of a 2006 dust fall in Beijing, they found that different provenance components are concentrated in different size fractions. Innocent et al. (2000) ana lyzed Nd isotopes in deep sea sediment from the Labrador Sea. They showed that the clay and silt fractions have different isotopic values and provenance, the silt being detrital material from the Canadian Shield and the clays being derived from deep water currents. As stated previously, the non silt fraction of the bulk samples is primarily clay sized material. Although not explicitly measured here, the Pb isotopic value of the non silt (clay sized) fraction can be estimated using the Isotopic Composition M ixing Model of Bacardit et al. (2012). Bacardit modeled the isotopic values of anthropogenic Pb in peat after measuring isotopes in core samples from pre anthropogenic time and post anthropogenic time. The equation used is similar to Equation 1 but with in dividual Pb isotope ratio s replacing the Pb concentrations. By establishing the pre anthropogenic baseline, they were able to calculate the isotopic values of the human input in the post anthropogenic samples. In my use of this model, the estimated silt an d non silt mass percentages are used to estimate the isotopic ratios for each fraction. Because of the low concentration of Pb in the non silt fraction, the isotopic value for this fraction must vary considerably from the overall bulk rock and silt isotopi c values. The isotopic values of this clay size fraction must be higher in both 208 Pb/ 204 Pb and 206 Pb/ 204 Pb and lower in 207 Pb/ 204 Pb to account for the ratios seen in th e silt fraction ( Figure 4 3 B and 4 3 D). Isotopic ratios for the different bedrock sourc es can be used to explain the isotopic ratios seen in this clay size fraction ( Figure 4 3A and 4 3 C). Whereas the bulk rock samples plot directly within the CPC field or are a mixture of Orca Valdez and

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66 Wrangellia/CMC metabasite, the estimated clay size fr action would plot outside the CPC field with a greater contribution from Orca/Valdez and less from Wran gellia/CMC metabasite (Figures 4 3B and 4 3 D). Further delineation of sediment provenance is discussed below. The difference in Pb isotopic ratios betwe en the Yakataga bulk and silt size fraction implies mudrock samples were disaggregated adequately. If silt samples contained substantial residual clay, the isotopic ratios of the silt would be the same as the bulk. In situ decay of U to Pb in the Yakataga silt is not a large influence on the isotopic ratios as the U/Pb ratio shows only slight correlation with 206 Pb/ 204 Pb (Tables 4 3 and 4 5). A strong correlation would be caused by decay of samples high in U to contribute to higher 206 Pb/ 204 Pb. This is in c ontrast to the Yakataga bulk analyses which show a stronger correlation between U/Pb and 206 Pb/ 204 Pb indicating they have been affected by some in situ decay of U to Pb (Tables 4 2 and 4 4). Yakataga Provenance Previous coarse grain provenance analyses of the Yakataga have indicated multiple sources, and analyses in this study of the dominant lithology (fine grain) support multiple sources but also provide some potential insight to temporal evolution of sources when only the silt fraction is considered. Si lt fraction elemental and Pb isotopic results reveal a difference in provenance between the conformable and unconformable stratigraphic sections. The conformable sections show a more felsic component with higher 206 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios and lower 207 Pb/ 204 Pb ratios, which likely reflects a mixing of recycled felsic CPC via the Kulthieth/Poul Creek formations with some input of Orca/Valdez. Bulk and silt ratios are much more similar than in the conformable sections, which would be expected if the s ource rocks were primarily

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67 composed of easily transported and mixed fine grain material, as is the case for the Kulthieth/Poul Creek and Orca/Valdez. In contrast, the unconformable sections have a stronger differentiation between the bulk and silt fracti ons. Elementally, the unconformable silt samples have more of a mafic source component in addition to a Pb isotopic signature that indicates a greater input of CMC metabasite or Wrangellia terrane. Two possible sources could account for the increase in maf ic input: the CMC metabasite belt or mafic volcanics of the Wrangellia terrane. Because the Yakataga has accumulated in close proximity to the exhuming metabasalts of the metamorphic core complex ( Figure 1 1 ), it is the likely source of this mafic componen t with lower 206 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios and higher 207 Pb/ 204 Pb ratios. The provenance difference between the two groups of sections could reflect relative temporal changes in accumulation, with the unconformable sections being deposited after the conformable sections. Conformable sections contain a larger dispersion in elemental and isotopic data, indicating mixing from more diverse sources. The felsic elemental signal implies erosion from the Kulthieth/Poul Creek and the Pb isotopic values indicat e a Kulthieth/Poul Creek (CPC) and Orca/Valdez source. Bedrock apatite U Th He ages from the St. Elias Range reveal rapid exhumation of Kultieth/Poul Creek rocks during the time of Yakataga accumulation (Berger et al., 2008; Spotila and Berger, 2010; Enkel man et al., 2010). The unconformity between Yakataga and Yakutat Group (Cretaceous) rocks in the east indicates substantial erosion of Eocene Miocene Kultieth/Poul Creek sediment (Witmer, 2009). Relatively older (>10 Ma) bedrock apatite U Th He ages in Chu gach/Orca Valdez rocks suggests lesser rates of erosion and a

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68 potentially smaller contribution of this source to the Yakataga (Berger et al., 2008; Spotila and Berger, 2010; Enkelmann et al., 2010). The stronger contrast in composition between the silt and bulk fraction of the unconformable sections could represent the transition to more input from the CMC as a source in the silt size fraction Throughout the Plio Pleistocene deposition of the Yakataga, the CMC has been exhumed in the eastern syntaxis of th e St. Elias orogen (Enkelmann et al. 2010). Exhumation of the metabasalt rocks in the CMC could provide increasing amounts of primarily eroded crystalline, mafic silt sized material. This spatial/temporal transition is also supported by the respective lith ofacies of the two regions. The unconformable sections are composed primarily of glacimarine (fjord like) sediments while the conformable sections are predominantly marine (submarine fan like) sediments with less prevalent glacial input (Witmer 2009). Conf ormable sections could have been deposited while erosion in the eastern syntaxis occurred. Once erosion was complete and deposition resumed in the unconformable sections, continued uplift in the eastern syntaxis within the CMC could have lead to a signific ant component of mafic sourced sedimentary material. The increased CMC signal could also represent a climatic transition, as the Cordilleran Ice sheet began to form where the elevation was highest (presumably at the syntaxis) where the CMC is present. An a dditional possibility is that the difference in provenance simply reflects a steady state geographic difference in bedrock geology. Kulthieth/Poul Creek and Orca/Valdez outcrops now surround the conformable sections whereas the unconformable sections have more of the CMC metabasite and backstop mafic rocks outcropping in their vicinity (CMC primarily located in the Orca Group) (Bruand et al. 2011; Pavlis et al. 2012). Choosing between these

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69 options would require better chronostratigraphic control of the sec tions, which is not available at present. There are many similarities when comparing our provenance results with those of previous detrital zircon studies on the coarse size fraction of the Yakataga (Perry et al. 2009; Witmer 2009 ; Headley et al. 2013 ). De trital zircon provenance reveals a mixture of plutonic sources from recycled CPC, Chugach terrane, and Wrangellia terrane sources. Within the context of this study, the overall provenance of the fine grained sedimentary rocks of the Yakataga is very simila r to that of the coarse grained rocks. I see a recycled sedimentary component, originally sourced from the felsic CPC, mixed with a younger mafic source, which detrital zircon studies would be less likely to pick up due to the lack of zircon in mafic rocks However, by including different stratigraphic sections within the Yakataga, I expand upon the published detrital zircon provenance studies. By using the isotopic and elemental techniques in this study I am able to more efficiently analyze a large set of samples from throughout the Yakataga formation. Detrital zircon analyses are laborious and can take a full day to analyze all zircons from just one sample. As a result, in the published zircon studies, only the overall provenance of the Yakataga is discus sed. Additionally, zircons are derived from specific rock types that may not sample mafic sourced protoliths. Here, I have presented shifts in provenance throughout the deposition of the Yakataga formation that the detrital zircon studies have not previous ly identified. Future Work Elemental and isotopic analyses of the clay size material could be used to investigate the difference in provenance between size fractions. Additional Pb isotopic

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70 analyses on the source regions, particularly the CMC would be use ful to further constrain the source of the mafic component. Comparisons with the detrital zircon data on a more detailed, bed by bed lithostratigraphic scale will help examine the difference in provenance between the sedimentary sections as a result of cha nges in sediment dispersal pathways. Sand sized feldspar Pb isotopic data could be compared with silt and bulk to better correlate with results from sand sized zircon analyses.

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71 Figure 5 1. Pri ncipal component analysis (PCA) of unaltered elemental dat a from the different possible source regions. Data from Bruand et al. (2012), Sisson et al. (2003), and Barker et al. (1992). Kulthieth/Poul Creek/Yakutat Group silt data come from this study. OV = Orca and Valdez groups. A. Principle component 1 (PC 1) ex plains 56% of the variance with Y, Ti, Cr, and Ni varying together opposite La, Nb, and Ce. B. Principle component 2 (PC 2) explains 36% of the variance. All elements vary together but the highest loading is from Ti. C. Samples plotted in principle compone nt space, PC 1 versus PC 2. The mafic metabasites are associated with low PC 1 (high in Cr, Ni, and Y) while the felsic plutons are high in PC 1 indicating high La, Nb, and Ce. Samples are separated very well by PC 1 with the CMC metabasites being one end member and Sanak Baranoff plutons being another. The sedimentary samples do not show much variation in PC 2, but negative loadings suggest an influence from Ti. PC2 likely reflects an elemental difference associated with minerals concentrated in crystallin e versus sedimentary material.

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72 Figure 5 2. PCA of the bulk fraction Yakataga samples. Symbol colors reflect different lithos tratigraphic sections (Figures 1 1 and 1 2). A. PC 1 explains 62% of the variance and shows similar associations and loading as Figure 6A. Y, La, Ce, vary toget her opposite Cr, Ni, Co, and Ti 206Pb/204Pb varies with the felsic associated elements. B. PC 2 explains 16% of the variance and is strongly controlled by Zr and Nb varying together. C. PC 3 explains 12% of the variance an d is controlled by Zr varying opposite everything else. PC 2 and 3 are most likely related to zircon content and high in Zr most likely indicates a coarser grain size. D. Samples plotted in principal component space, PC 1 versus PC 2, showing that the unco nformable sections have a more mafic provenance component and that the conformable sections have higher zircon content.

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73 Figure 5 3. PCA of the silt fraction Yakataga samples. Symbol colors same as Figure 5 2 A. PC 1 explains 48% of the variance and a gain shows similar mafic felsic elementa l associations as source ( Figure 5 1A) and bulk fraction ( Figure 5 2 A). 206Pb/204Pb varies with the felsic associated elements. B. PC 2 explains 21% of the variance and has elemental associations similar to PC 2 in s ource samples (Figure 5 1 B). C. Samples plotted in PC 1 versus PC 2principal component space. Unconformable section samples are indicated to have a more mafic source influence. Conformable section silt samples are more negative in PC 1, indicating more fel sic source influence. More scatter is seen in PC2 of conformable section silt samples suggesting a wider range of source rock types.

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74 CHAPTER 6 CONCLUSIONS Results of our Yakataga Formation mudrock provenance analyses reveal that elemental and isotopic an alyses of the silt size fraction can provide a more diagnostic signal of sediment sources than bulk rock analyses. The silt fraction can be separated from indurated mudrocks, providing a novel method to address provenance changes of buried mudrocks. A synt hesis of the bulk rock and silt size elemental and Pb isotopic results indicates a spatial (and likely temporal) difference in mudrock provenance. The transition is from a predominantly recycled Coast Plutonic Complex (Kulthieth/Poul Creek formations) and Chugach accretionary (Orca/Valdez) source in conformable (older) section to an increasing mafic component, likely from the rapidly exhuming CMC metabasite belt, predominantly seen in the unconformable (younger) stratigraphic sections in the eastern part of the study area. This result is consistent with the conclusions of detrital zircon studies on sandstones from the Yakataga. In contrast to these zircon studies, I provide additional stratigraphic context to our provenance and demonstrate shifts in provenan ce between the conformable and unconformable sections of the Yakataga formation. The difference in provenance is most clearly demonstrated in the silt fraction, where samples from the unconformable sections are more enriched in elements associated with maf ic rocks (Cr, Ni, Co) and have a lower 206 Pb/ 204 Pb and 208 Pb/ 204 Pb ratio than those from the conformable sections. This provenance difference also is seen in the elemental results of the bulk size fraction but not as clearly in the isotopic results. In a ddition to the provenance differences between the stratigraphic sections, I also demonstrated a different provenance between the bulk sediment and silt fraction

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75 within individual samples through Pb isotopic data. While previous studies have shown a differe nce in provenance between size fractions using other isotopic systems, this is the first evidence based on Pb isotopes in mudrocks. Based on mixing models of elemental and Pb isotopic data, the non silt fraction is mostly clay sized material with a provena nce likely from a recycled accretionary prism (Orca Valdez) source whereas the silt has a larger component of first generation eroded crystalline/metamorphic material. The stratigraphic context of the sample also affects the difference in provenance betwe en size fractions. Unconformable (younger) sections show a wider range between the silt and bulk isotopic values indicating that these sections contain a larger component of the newly eroded crystalline/metamorphic material. The observed elemental and iso topic differences between the bulk and silt fraction of these mudrocks also reveals the value of separating and analyzing only the silt size fraction, as the more differentiated isotopic and elemental signature of the silt fraction is obscured in the analy ses of the bulk sedimentary material. The Yakataga samples analyzed here are at the limit of the efficacy of the sediment disaggregation method. The technique used here would likely not be able to disaggregate more indurated or cemented mudrocks.

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76 APPEND IX A SILT SEM PHOTOGRAPHS SEM photographs of Yakataga and modern glacial silt samples. All photographs by author. Figure A 1. SEM photograph of silt sample WI1 035

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77 Figure A 2. SEM photograph of silt sample WI1 035

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78 Figure A 3. SEM photograph of silt sample WI1 224.

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79 Figure A 4. SEM photograph of silt sample SV3 089.

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80 Figure A 5 SEM photograph of silt sample SV3 089

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81 Figure A 6. SEM photograph of silt sample SV3 089.

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82 Figure A 7. SEM photograph of silt sample KM1 16.

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83 Figu re A 8. SEM photograph of silt sample KM1 16.

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84 Figure A 9. SEM photograph of silt sample KM1 16.

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85 Figure A 10. SEM photograph of silt sample CY2 36.

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86 Figure A 11. SEM photograph of silt sample 07YA08.

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87 Figure A 12. SEM photograph of silt s ample 07YA08.

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88 APPENDIX B SILT MICROSCOPE PHOTOGRAPHS Optical microscope photographs of Yakataga and modern glacial silt samples. All photographs by author. Figure B 1. Optical microscope photograph of silt sample 07YA08.

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89 Figure B 2. Optical micr oscope photograph of silt sample 07YA08.

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90 Figure B 3. Optical microscope photograph of silt sample 07YA08.

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91 Figure B 4. Optical microscope photograph of silt sample 07YA08.

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92 Figure B 5. Optical microscope photograph of silt sample 07YA08.

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93 F igure B 6. Optical microscope photograph of silt sample 07YA08.

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94 Figure B 7. Optical microscope photograph of silt sample 07YA08.

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95 Figure B 8. Optical microscope photograph of silt sample 07YA08.

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96 Figure B 9. Optical microscope photograph of s ilt sample 07YA08.

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97 Figure B 10. Optical microscope photograph of silt sample KI1 209.

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98 Figure B 11. Optical microscope photograph of silt sample KI1 209.

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99 Figure B 12. Optical microscope photograph of silt sample KI1 209.

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100 Figure B 13. Opt ical microscope photograph of silt sample KI1 209.

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101 Figure B 14. Optical microscope photograph of silt sample KM1 16.

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102 Figure B 15. Optical microscope photograph of silt sample KM1 16.

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103 Figure B 16. Optical microscope photograph of silt sample KM1 16.

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104 Figure B 17. Optical microscope photograph of silt sample KM1 16.

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105 Figure B 18. Optical microscope photograph of silt sample SV1 042.

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106 Figure B 19. Optical microscope photograph of silt sample SV1 042.

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107 Figure B 20. Optical microsc ope photograph of silt sample SV1 042.

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108 Figure B 21. Optical microscope photograph of silt sample SV1 042.

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109 Figure B 22. Optical microscope photograph of silt sample WI2 035.

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110 Figure B 23 Optical microscope photograph of silt sample WI2 035.

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111 Figure B 24. Optical microscope photograph of silt sample WI2 035.

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112 Figure B 25. Optical microscope photograph of silt sample WI2 035.

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113 LIST OF REFERENCES AITCHISON, J., 1982, The statistical analysis of compositional data: Journal of the Royal Sta tistical Society. Series B (Methodological), p. 139 177. ALEINIKOFF, J.N., DUSELBACON, C., FOSTER, H.L., and NOKLEBERG, W.J., 1987, Lead isotopic fingerprinting of tectonostratigraphic terranes, east central Alaska : Canadian Journal of Earth Sciences, v. 2 4. ALIZAI, A., CLIFT, P.D., GIOSAN, L., VANLANINGHAM, S., HINTON, R., TABREZ, A.R., DANISH, M., and EIMF, 2011, Pb isotopic variability in the modern Pleistocene Indus River system measured by ion microprobe in detrital K feldspar grains: Geochimica Et Cos mochimica Acta, v. 75, p. 4771 4795. ANDREWS, J.T., and EBERL, D.D., 2011, Surface (sea floor) and near surface (box cores) sediment mineralogy in Baffin Bay as a key to sediment provenance and ice sheet variations: Canadian Journal of Earth Sciences, v. 4 8. BARBERA, G., LO GIUDICE, A., MAZZOLENI, P., and PAPPALARDO, A., 2009, Combined statistical and petrological analysis of provenance and diagenetic history of mudrocks: Application to Alpine Tethydes shales (Sicily, Italy): Sedimentary Geology, v. 213. BA RKER, F., FARMER, G.L., AYUSO, R.A., PLAFKER, G., and LULL, J.S., 1992, The 50 ma granodiorite of the eastern gulf of Alaska melting in an accretionary prism in the fore arc : Journal of Geophysical Research Solid Earth, v. 97. BERGER, A.L., GULICK, S.P.S ., SPOTILA, J.A., UPTON, P., JAEGER, J.M., CHAPMAN, J.B., WORTHINGTON, L.A., PAVLIS, T.L., RIDGWAY, K.D., WILLEMS, B.A., and MCALEER, R.J., 2008, Quaternary tectonic response to intensified glacial erosion in an orogenic wedge: Nature Geoscience, v. 1, p. 793 799. BHATIA, M.R., and CROOK, K.A.W., 1986, Trace element characteristics of graywackes and tectonic setting discrimination of sedimentary basins : Contributions to Mineralogy and Petrology, v. 92. BRENAN, J.M., SHAW, H.F., RYERSON, F.J., and PHINNEY, D .L., 1995, Experimental determination of trace element partitioning between pargasite and a synthetic hydrous andesitic melt : Earth and Planetary Science Letters, v. 135, p. 1 11. BRUAND, E., GASSER, D., BONNAND, P., and STUEWE, K., 2011, The petrology and geochemistry of a metabasite belt along the southern margin of Alaska: Lithos, v. 127, p. 282 297.

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114 CAMERON, E.M., and HATTORI, K., 1997, Strontium and neodynium isotope ratios in the Fraser River, British Columbia: a riverine transect across the Cordiller an orogen: Chemical geology, v. 137, p. 243 253. CHAPMAN, J.B., PAVLIS, T.L., BRUHN, R.L., WORTHINGTON, L.L., GULICK, S.P.S., and BERGER, A.L., 2012, Structural relationships in the eastern syntaxis of the St. Elias orogen, Alaska: Geosphere, v. 8, p. 105 126. CLIFT, P.D., VAN LONG, H., HINTON, R., ELLAM, R.M., HANNIGAN, R., TAN, M.T., BLUSZTAJN, J., and DUC, N.A., 2008, Evolving east Asian river systems reconstructed by trace element and Pb and Nd isotope variations in modern and ancient Red River Song Hon g sediments: Geochemistry Geophysics Geosystems, v. 9. COWAN, E.A., CHRISTOFFERSEN, P., and POWELL, R.D., 2012, Sedimentological signature of a deformable bed preserved beneath an ice stream in a late Pleistocene glacial sequence, Ross Sea, Antarctica : Jou rnal of Sedimentary Research, v. 82. CULLERS, R., 1988, Mineralogical and chemical changes of soil and stream sediment formed by intense weathering of the Danburg granite, Georgia USA: Lithos, v. 21. CURRAN, K.J., HILL, P.S., MILLIGAN, T.G., COWAN, E.A., SYVITSKI, J.P.M., and KONINGS, S.M., 2004, Fine grained sediment flocculation below the Hubbard Glacier meltwater plume, Disenchantment Bay, Alaska: Marine Geology, v. 203. DINELLI, E., TATEO, F., and SUMMA, V., 2007, Geochemical and mineralogical proxies for grain size in mudstones and siltstones from the Pleistocene and Holocene of the Po River alluvial plain, Italy: Special Papers Geological Society of America v. 420, p. 25. DUMOULIN, J.A., 1987, Sandstone composition of the Valdez and Orca Groups, Prin ce William Sound, Alaska, US Government Printing Office. ENKELMANN, E., ZEITLER, P., GARVER, J., PAVLIS, T., and HOOKS, B., 2010, The thermochronological record of tectonic and surface process interaction at the Yakutat North American collision zone in sou theast Alaska: American Journal of Science, v. 310, p. 231. EWART, A., and GRIFFIN, W.L., 1994, Application of proton microprobe data to trace element partitioning in volcanic rocks : Chemical Geology, v. 117, p. 251 284. EYLES, C., EYLES, N., and LAGOE, M. 1991, The Yakataga Formation; a late Miocene to Pleistocene record of temperate glacial marine sedimentation in the Gulf of Alaska: Glacial Marine Sedimentation. Geological Society of America Special Paper, v. 261, p. 159 180.

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115 EYLES, N., EYLES, C.H., and MIALL, A.D., 1983, Lithofacies types and vertical profile models an alternative approach to the description and environmental interpretation of glacial diamict and diamictite sequences : Sedimentology, v. 30, p. 393 410. FARMER, G.L., AYUSO, R., and PLAF KER, G., 1993, A Coast Mountains provenance for the Valdez and Orca groups, southern Alaska, based on Nd, Sr, and Pb isotopic evidence : Earth and Planetary Science Letters, v. 116, p. 9 21. FENG, J. L., ZHU, L. P., ZHEN, X. L., and HU, Z. G., 2009, Grain s ize effect on Sr and Nd isotopic compositions in eolian dust: Implications for tracing dust provenance and Nd model age: Geochemical Journal, v. 43, p. 123 131. FINZEL, E.S., TROP, J.M., RIDGWAY, K.D., and ENKELMANN, E., 2011, Upper plate proxies for flat slab subduction processes in southern Alaska: Earth and Planetary Science Letters, v. 303, p. 348 360. FLOWERDEW, M.J., TYRRELL, S., and PECK, V.L., 2012a, Inferring sites of subglacial erosion using the Pb isotopic composition of ice rafted feldspar: Exam ples from the Weddell Sea, Antarctica: Geology. FLOWERDEW, M.J., TYRRELL, S., RILEY, T.R., WHITEHOUSE, M.J., MULVANEY, R., LEAT, P.T., and MARSCHALL, H.R., 2012b, Distinguishing East and West Antarctic sediment sources using the Pb isotope composition of d etrital K feldspar: Chemical Geology, v. 292, p. 88 102. GARVER, J.I., and SCOTT, T.J., 1995, Trace elements in shale as indicators of crustal provenance and terrane accretion in the southern Canadian cordillera : Geological Society of America Bulletin, v. 107. GASSER, D., BRUAND, E., STWE, K., FOSTER, D.A., SCHUSTER, R., FGENSCHUH, B., and PAVLIS, T., 2011, Formation of a metamorphic complex along an obliquely convergent margin: Structural and thermochronological evolution of the Chugach Metamorphic Compl ex, southern Alaska: Tectonics, v. 30, p. TC2012. GASSER, D., RUBATTO, D., BRUAND, E., and STUEWE, K., 2012, Large scale, short lived metamorphism, deformation, and magmatism in the Chugach metamorphic complex, southern Alaska: A SHRIMP U Pb study of zirco ns: Geological Society of America Bulletin, v. 124. GODWIN, C.I., and SINCLAIR, A.J., 1982, Average lead isotope growth curves for shale hosted zinc lead deposits, Canadian cordillera : Economic Geology, v. 77. GULICK, S., FREYMUELLER, J., KOONS, P., JAEGER J., PAVLIS, T., and POWELL, R., 2004, Examining tectonic climatic interactions in Alaska and the northeastern Pacific: Eos, Transactions American Geophysical Union, v. 85, p. 433.

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116 HALLET, B., HUNTER, L., and BOGEN, J., 1996, 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. HEADLEY, R., HALLET, B., ROE, G., WADDINGTON, E.D., and RIGNOT, E., 2012, Spatial distribution of glacial erosion rates in the St. Elias range, Alaska, inferred from a realistic model of glacier dynamics: Journal of Geophysical Research Earth Surface, v. 117. HEADLEY, R.M., ENKELMANN, E., and HALLET, B., 2013, Examination of the interplay between glacial processes and exhumation in the Sai nt Elias Mountains, Alaska: Geosphere, v. 9, p. 1 13. HEMMING, S.R., BROECKER, W.S., SHARP, W.D., BOND, G.C., GWIAZDA, R.H., MCMANUS, J.F., KLAS, M., and HAJDAS, I., 1998, Provenance of Heinrich layers in core V28 82, northeastern Atlantic: Ar 40/Ar 39 age s of ice rafted hornblende, Pb isotopes in feldspar grains, and Nd Sr Pb isotopes in the fine sediment fraction: Earth and Planetary Science Letters, v. 164, p. 317 333. HUDSON, T., PLAFKER, G., and PETERMAN, Z.E., 1979, Paleogene anatexis along the Gulf o f Alaska margin : Geology, v. 7. INNOCENT, C., FAGEL, N., and HILLAIRE MARCEL, C., 2000, Sm Nd isotope systematics in deep sea sediments: clay size versus coarser fractions: Marine Geology, v. 168. JAEGER, J., HALLET, B., PAVLIS, T., SAUBER, J., LAWSON, D., MILLIMAN, J., POWELL, R., ANDERSON, S.P., and ANDERSON, R., 2001, Orogenic and glacial research in pristine southern Alaska: Eos, Transactions American Geophysical Union, v. 82, p. 213 216. JENNER, F.E., and O'NEILL, H.S.C., 2012, Analysis of 60 elements in 616 ocean floor basaltic glasses: Geochemistry Geophysics Geosystems, v. 13. KAMENOV, G.D., BRENNER, M., and TUCKER, J.L., 2009, Anthropogenic versus natural control on trace element and Sr Nd Pb isotope stratigraphy in peat sediments of southeast Flori da (USA), similar to 1500 AD to present: Geochimica Et Cosmochimica Acta, v. 73. KESSEL, R., SCHMIDT, M.W., ULMER, P., and PETTKE, T., 2005, Trace element signature of subduction zone fluids, melts and supercritical liquids at 120 180 km depth: Nature, v. 437, p. 724 727. KOGISO, T., TATSUMI, Y., and NAKANO, S., 1997, Trace element transport during dehydration processes in the subducted oceanic crust .1. Experiments and implications for the origin of ocean island basalts: Earth and Planetary Science Letters v. 148, p. 193 205.

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117 KRAVCHUK, I.F., CHERNYSHEVA, I., and URUSOV, V.S., 1981, Element distribution between plagioclase and groundmass as an indicator of crystallization conditions of the basalts in the southern vent of Tolbachik volcano, Geochem: Geochem. Intl, v. 17, p. 18 24. LAGOE, M.B., EYLES, C.H., and EYLES, N., 1989, Paleoenvironmental significance of foraminiferal biofacies in the glaciomarine Yakataga Formation, Middleton Island, Gulf of Alaska : Journal of Foraminiferal Research, v. 19, p. 194 20 9. LAGOE, M.B., EYLES, C.H., EYLES, N., and HALE, C., 1993, Timing of late Cenozoic tidewater glaciation in the far north Pacific : Geological Society of America Bulletin, v. 105, p. 1542 1560. LAMASKIN, T.A., DORSEY, R.J., and VERVOORT, J.D., 2008, Tectoni c controls on mudrock geochemisry, Mesozoic rocks of eastern Oregon and western Idaho, USA: Implications for cordilleran tectonics : Journal of Sedimentary Research, v. 78. MARINCOVICH, L., 1990, Molluscan evidence for early middle Miocene marine glaciation in southern Alaska : Geological Society of America Bulletin, v. 102. MCDANIEL, D.K., MCLENNAN, S.M., and HANSON, G.N., 1997, Provenance of Amazon fan muds: constraints from Nd and Pb isotopes: Proceedings of the Ocean Drilling Program. Scientific results, p. 169 176. MCKENZIE, D., and ONIONS, R.K., 1991, Partial melt distributions from inversion of rare earth element concentrations : Journal of Petrology, v. 32, p. 1021 1091. MCLENNAN S.M., 2001, Relationships between the trace element composition of sedime ntary rocks and upper continental crust: Geochemistry Geophysics Geosystems, v. 2. MIALL, A.D., 1985, Sedimentation on an early Proterozoic continental margin under glacial influence the Gowganda Formation (Huronian), Elliot Lake area, Ontario, Canada : S edimentology, v. 32. NAJMAN, Y., 2006, The detrital record of orogenesis: A review of approaches and techniques used in the Himalayan sedimentary basins: Earth Science Reviews, v. 74, p. 1 72. NESBITT, H.W., YOUNG, G.M., MCLENNAN, S.M., and KEAYS, R.R., 1996, Effects of chemical weathering and sorting on the petrogenesis of siliciclastic sediments, with implications for provenance studies: Journal of Geology, v. 104, p. 525 542. PAVLIS, T.L., CH APMAN, J.B., BRUHN, R.L., RIDGWAY, K., WORTHINGTON, L.L., GULICK, S.P.S., and SPOTILA, J., 2012, Structure of the actively deforming fold thrust belt of the St. Elias orogen with implications for glacial exhumation and three dimensional tectonic processes: Geosphere, v. 8.

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118 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: Journal of Geology, v. 117, p. 156 173. PIER CE, E.L., WILLIAMS, T., VAN DE FLIERDT, T., HEMMING, S.R., GOLDSTEIN, S.L., and BRACHFELD, S.A., 2011, Characterizing the sediment provenance of East Antarctica's weak underbelly: The Aurora and Wilkes sub glacial basins: Paleoceanography, v. 26. PIPER, D. Z., and LINK, P.K., 2002, An upwelling model for the Phosphoria sea: A Permian, ocean margin sea in the northwest United States: Aapg Bulletin, v. 86, p. 1217 1235. PLAFKER, G., MOORE, J.C., and WINKLER, G.R., 1994, Geology of the southern Alaska margin, i n Plafker, G., and Berg, H.C., eds., The Geology of Alaska, Geological Society of America, p. 389 448. PLAFKER, G., NOKLEBERG, W.J., and LULL, J.S., 1989, Bedrock geology and tectonic evolution of the Wrangellia, Peninsular, and Chugach Terranes along the trans Alaska crustal transect in the Chugach Mountains and southern Copper River basin, Alaska : Journal of Geophysical Research Solid Earth and Planets, v. 94, p. 4255 4295. POPPE, L.J., PASKEVICH, V.F., HATHAWAY, J.C., and BLACKWOOD, D.S., 2001, A laborat ory manual for X ray powder diffraction: US Geological Survey Open File Report, v. 1, p. 1 88. POWELL, R.D., and MOLNIA, B.F., 1989, Glacimarine sedimentary processes, facies and morphology of the south southeast Alaska shelf and fjords : Marine Geology, v. 85, p. 359 390. REA, D., and SNOECKX, H., 1995, Sediment fluxes in the Gulf of Alaska: Paleoceanographic record from Site 887 on the Patton Murray Seamount platform, p. 247 256. ROLLINSON, H.R., 1993, Using geochemical data: evaluation, presentation, inte rpretation, v. 352. ROY, M., HEMMING, S.R., and PARENT, M., 2009, Sediment sources of northern Quebec and Labrador glacial deposits and the northeastern sector of the Laurentide Ice Sheet during ice rafting events of the last glacial cycle: Quaternary Scie nce Reviews, v. 28. RUDNICK, R.L., and FOUNTAIN, D.M., 1995, Nature and composition of the continental crust a lower crustal perspective : Reviews of Geophysics, v. 33. SISSON, T.W., 1994, Hornblende melt trace element partitioning measured by ion micropr obe : Chemical Geology, v. 117, p. 331 344.

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119 SISSON, V.B., POOLE, A.R., HARRIS, N.R., BURNER, H.C., PAVLIS, T.L., COPELAND, P., DONELICK, R.A., and MCLELLAND, W.C., 2003, Geochemical and geochronologic constraints for genesis of a tonalite trondhjemite suite and associated mafic intrusive rocks in the eastern Chugach Mountains, Alaska: A record of ridge transform subduction: Special Papers Geological Society Of America p. 293 326. TROP, J.M., HART, W.K., SNYDER, D., and IDLEMAN, B., 2012, Miocene basin devel opment and volcanism along a strike slip to flat slab subduction transition: Stratigraphy, geochemistry, and geochronology of the central Wrangell volcanic belt, Yakutat North America collision zone: Geosphere, v. 8, p. 805 834. VANLANINGHAM, S., DUNCAN, R .A., and PISIAS, N.G., 2006, Erosion by rivers and transport pathways in the ocean: A provenance tool using (40)Ar (39)Ar incremental heating on fine grained sediment: Journal of Geophysical Research Earth Surface, v. 111. VERVOORT, J.D., PLANK, T., and PR YTULAK, J., 2011, The Hf Nd isotopic composition of marine sediments: Geochimica Et Cosmochimica Acta, v. 75. WITMER, J.W., 2009, Neogene deposition, provenance, and exhumation along a tectonically active, glaciated continental margin, Yakataga and Redwood Formations, southern Alaska syntaxis. YANG, Y.L., and APLIN, A.C., 1997, A method for the disaggregation of mudstones: Sedimentology, v. 44, p. 559 562. YOUNG, G.M., and NESBITT, H.W., 1999, Paleoclimatology and provenance of the glaciogenic Gowganda Form ation (Paleoproterozoic), Ontario, Canada: A chemostratigraphic approach: Geological Society of America Bulletin, v. 111.

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120 BIOGRAPHICAL SKETCH Dylan Loss had his appendix removed during his first year at the University of Wisconsin Madison. It was around t his time that Dylan narrowed down his academic interests to geology and animal husbandry. He constantly wavered between his love for sedimentary processes and the intricacies of the bovine digestive system. Likely fueled by the delusions brought about by a post surgical pain medication supply, Dylan decided to major in geology. After completing his BS in geology with honors Dylan followed in the footsteps of the actor Stephen Root (credits include Milton Waddams in Office Space) and attended the University of Florida in Gainesville. There he earned his MS after completing a study on sedimentary provenance in the Yakutat terrain (along the Gulf of Alaska). Outside of academia, Dylan is an avid rock climber, outdoorsman, and naturalist. In other words, he is t he embodiment of the clich geologist. After his gradu ate studies he travel ed throughout Western Europe to experience the world (again incredibly clich). Ultimately, he would love to settle down behind an oak desk working for a large, profitable, multinat ional oil company.