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Exposure Age and Climate Controls of Weathering in Deglaciated Watersheds of Western Greenland

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Title:
Exposure Age and Climate Controls of Weathering in Deglaciated Watersheds of Western Greenland
Creator:
Scribner, Cecilia A
Place of Publication:
[Gainesville, Fla.]
Florida
Publisher:
University of Florida
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english
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1 online resource (77 p.)

Thesis/Dissertation Information

Degree:
Master's ( M.S.)
Degree Grantor:
University of Florida
Degree Disciplines:
Geology
Geological Sciences
Committee Chair:
MARTIN,ELLEN ECKELS
Committee Co-Chair:
MARTIN,JONATHAN BOWMAN
Committee Members:
JAEGER,JOHN M
Graduation Date:
8/9/2014

Subjects

Subjects / Keywords:
Carbonates ( jstor )
Ions ( jstor )
Isotopes ( jstor )
Lakes ( jstor )
Minerals ( jstor )
Sediments ( jstor )
Silicates ( jstor )
Solutes ( jstor )
Watersheds ( jstor )
Weathering processes ( jstor )
Geological Sciences -- Dissertations, Academic -- UF
greenland -- hydrogeochemistry -- isotopes -- watersheds -- weathering
City of Lake Helen ( local )
Genre:
bibliography ( marcgt )
theses ( marcgt )
government publication (state, provincial, terriorial, dependent) ( marcgt )
born-digital ( sobekcm )
Electronic Thesis or Dissertation
Geology thesis, M.S.

Notes

Abstract:
Sediments deposited as glaciers retreat chemically weather at rates faster than the global average, altering seawater nutrient, ionic, and isotopic compositions across glacial-interglacial cycles. Greenland discharges more water annually to the ocean than Antarctica, with about half draining directly from the Greenland Ice Sheet (GIS) and half from deglacial watersheds that drain annual precipitation and melting permafrost, rather than glacial waters. As the GIS retreats, weathering solute fluxes from the deglaciated margin will make up an increasing fraction of the total flux, but few studies have investigated the primary weathering reactions and controls on deglacial weathering. We investigate the effect of exposure age and precipitation on weathering intensity by comparing major ion composition, Sr isotopes, and mineral saturation in waters and sediments across four deglacial watersheds spanning a longitudinal transect from the coast near Sisimiut towards the GIS near Kangerlussuaq, western Greenland The transect is underlain by Archean gneiss and a gradient in moraine ages (from ~7.5-8.0 ka inland to ~10 ka at the coast) and precipitation-evaporation (from -150mm/yr inland to +150mm/yr at the coast). From inland to coastal watersheds, water compositions shift from HCO3- to SO42- dominated, likely due to trace carbonate dissolution in inland watersheds and sulfide mineral oxidation near the coast. All watersheds experience lower silica proportions than expected from felsic weathering environments, but coastal watersheds have ~2x more silica than inland watersheds. Streamwater 87Sr/86Sr from one inland and one coastal watershed average 0.732 and 0.713 respectively, and delta 87Sr/86Sr (water-bedload) decreases from 0.018 inland to 0.005 at the coast. Changes in major element and 87Sr/87Sr from inland to coastal watersheds reflect an approach toward congruent weathering in coastal watersheds. Inland watersheds exhibit a lesser extent of weathering than coastal watersheds. The shift from carbonate weathering products and incongruent delta 87Sr/87Sr occurs over timescales consistent with previous alpine studies (~10s of ky). The negative water balance inland may extend the timescale over which trace carbonate dissolves. Changes across deglacial watersheds of western Greenland indicate that solute fluxes to the oceans will likely change as continental glaciers retreat and the relative proportion of deglacial to proglacial runoff increases. ( en )
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
Source of Description:
Description based on online resource; title from PDF title page.
Source of Description:
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Thesis:
Thesis (M.S.)--University of Florida, 2014.
Local:
Adviser: MARTIN,ELLEN ECKELS.
Local:
Co-adviser: MARTIN,JONATHAN BOWMAN.
Electronic Access:
RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2016-08-31
Statement of Responsibility:
by Cecilia A Scribner.

Record Information

Source Institution:
UFRGP
Rights Management:
Applicable rights reserved.
Embargo Date:
8/31/2016
Resource Identifier:
968786257 ( OCLC )
Classification:
LD1780 2014 ( lcc )

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EXPOSURE AGE AND CLIMATE CONTROLS OF WEATHERING IN DE GLACIATED WATERSHEDS OF WESTERN GREENLAND By CECILIA ANNE SCRIBNER A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2014

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© 2014 Cecilia Anne Scribner

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To my Family

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4 ACKNOWLEDGMENTS Thank you to my advisors, Drs . Ellen and Jon Martin, for including me in the visi on for this project from the onset . Thank you to Kelly Deuerling for training in laboratory and field procedures and help throughout the project . Thank you, Mom, Dad, Sara, and Taylor for all of your love and support. Thank you Candler for helping me keep the destination in sight. I would like to thank George Kamenov and Jason Curtis at the University of Florida wi th assistance in isotopic analyses. Daniel Collazo, Mike Davlantez, and Andrea Portier assisted in field collection and Adam Marshall provided laboratory assistance. I thank the Government of Greenland for allowing our field team to collect samples, Kangerlussuaq International Science Station (KISS) staff for hosting my team and providing laboratory space, as well as CH2MHILL for helping to coordinate field logistics. This project was funded by NSF grant #ARC 1203773.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF TABLES ................................ ................................ ................................ ............ 7 LIST OF FIGURES ................................ ................................ ................................ .......... 8 ABSTRACT ................................ ................................ ................................ ..................... 9 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .... 11 2 SITE DESCRIPTION ................................ ................................ .............................. 17 3 METHODS ................................ ................................ ................................ .............. 22 Field Sampling Procedures ................................ ................................ ..................... 22 Water Analyses ................................ ................................ ................................ ....... 23 Sediment Analyses ................................ ................................ ................................ . 25 Saturation Indices ................................ ................................ ................................ ... 25 4 RESULTS ................................ ................................ ................................ ............... 26 Field parameters (Specific Conductivity, pH, and Dissolved Oxygen) .................... 26 Major element and Sr concentrations ................................ ................................ ..... 27 Saturation Indices ................................ ................................ ................................ ... 29 Radiogenic Sr ................................ ................................ ................................ ......... 29 5 DISCUSSION ................................ ................................ ................................ ......... 40 Weathering Mineralogy ................................ ................................ ........................... 40 Chemical Weathering Intensity ................................ ................................ ............... 45 Potential Causes for Differences in Coastal and Inland Weathering ....................... 48 Weathering Rate ................................ ................................ ................................ ..... 49 6 CONCLUSIONS ................................ ................................ ................................ ..... 51 APPENDIX A STABLE ISOTOPES ................................ ................................ ............................... 54 B SISIMIUT DATA ................................ ................................ ................................ ...... 55 C NERUMAQ DATA ................................ ................................ ................................ ... 58

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6 D QORLORTOQ DATA ................................ ................................ .............................. 62 E LAKE HELEN DATA ................................ ................................ ............................... 66 LIST OF REFERENCES ................................ ................................ ............................... 69 BIOGRAPHICAL SKETCH ................................ ................................ ............................ 77

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7 LIST OF TABLES Table page 2 1 Sample site location and collection dates. ................................ .......................... 21 4 1 Summary of major Ion and Strontium concentration with distance from the coast.. ................................ ................................ ................................ ................. 3 9 B 1 Sisimiut field data. ................................ ................................ .............................. 55 B 2 Sisimiut stable isotope and major ion data. ................................ ........................ 56 B 3 Sisimiut Minor Element Data. ................................ ................................ ............. 57 C 1 Nerumaq field data. ................................ ................................ ............................ 58 C 2 Nerumaq stable isotope and major ion data. ................................ ...................... 59 C 3 Nerumaq Minor Element Data. ................................ ................................ ........... 60 C 4 Nerumaq radiogenic isotope data. ................................ ................................ ...... 61 D 1 Qorlortoq field data. ................................ ................................ ............................ 62 D 2 Qorlortoq stable isotope and major ion data. ................................ ...................... 63 D 3 Nerumaq Minor Element Data. ................................ ................................ ........... 64 D 4 Qorlortoq Radiogenic Isotope Data. ................................ ................................ ... 65 E 1 Lake Helen Field Data. ................................ ................................ ....................... 66 E 2 Lake Helen Stable Isotope and Major Ion Data. ................................ ................. 67 E 3 Lake Helen Minor Element Data. ................................ ................................ ........ 68

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8 LIST OF FIGURES Figur e page 2 1 Sample Locations. ................................ ................................ .............................. 20 4 1 Major ion ternary plots showing ion proportions in all watersheds ...................... 31 4 2 Na + versus Cl molar concentrations. ................................ ................................ .. 32 4 3 SO 4 2 versus Cl molar concentrations ................................ ................................ 33 4 4 Silica versus Ca 2+ molar concentrations ................................ ............................. 34 4 5 Dissolved Ca 2+ versus Sr ................................ ................................ .................... 35 4 6 Saturation indices of key minerals plotted by watershed. ................................ ... 36 4 7 87 Sr /86 Sr ratios for bedload fractions (< 2mm )and waters ................................ .. 37 4 8 87 Sr /86 Sr versus Ca/Sr ................................ ................................ ......................... 38 A 1 D versus ................................ ........................ 54

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9 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science EXPOSURE AGE AND CLIMATE CONTROLS OF WEATHERING IN DEGLACIATED WATERSHEDS OF WES TERN GREENLAND By Cecilia Scribner August 2014 Chair: Ellen Martin Cochair: Jon Martin Major: Geolog ical Sciences Sediments deposited as glaciers retreat chemically weather at rates faster than the global average, altering seawater nutrient, ionic, and isotopic compositions across glacial interglacial cycles. Greenland discharges more water annually to the ocean than Antarctica, with about half draining directly from the Greenland Ice Sheet (GIS) and half from deglacial watersheds that drain annual precipitation and melting permafrost, rather than glacial waters. As the GIS retreats, weathering solute fluxes from the deglaciated margin will make up an increasing fracti on of the total flux, but few studies have investigated the primary weathering reactions and controls on deglacial weathering. We investigate the effect of exposure age and precipitation on weathering intensity by comparing major ion composition, Sr isotop es, and mineral saturation in waters and sediments across four deglacial watersheds spanning a longitudinal transect from the coast near Sisimiut towards the GIS near Kangerlussuaq, western Greenland The transect is underlain by Archean gneiss and a gradie nt in moraine ages (from ~7.5 8.0 ka inland to ~10 ka at the coast) and precipitation evaporation (from 150mm/yr inl and to +150mm/yr at the coast) . From inland to coastal watersheds, water compositions shift

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10 from HCO 3 to SO 4 2 dominated, likely due to tr ace carbonate dissolution in inland watersheds and sulfide mineral oxidation near the coast. All watersheds experience lower silica proportions than expected from felsic weathering environments , but coastal watersheds have ~2x more silica than inland water sheds. Streamwater 87 Sr/ 86 Sr from one inland and one coastal watershed average 0.732 and 0.713 respectively, and 87 Sr/ 86 Sr (water bedload) decreases from 0.018 inland to 0.005 at the coast. Changes in major element and 87 Sr/ 87 Sr from inland to coastal wat ershed s reflect an approach toward congruent weathering in coastal watersheds. Inland watersheds exhibit a lesser extent of weathering than coastal watersheds. The shift from carbonate weathering 87 Sr/ 87 Sr occur s over timescales c onsistent with previous alpine studies (~10s of k y). The negative water balance inland may extend the timescale over which trace carbonate dissolves. Changes across deglacial watersheds of western Greenland indicate that solute fluxes to the oceans will likely change as continental glaciers retreat and the relative proportion of deglacial to proglacial runoff increases .

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11 CHAPTER 1 INTRODUCTION In most settings, c hemical weathering rates are driven by elevated temperature and precipitation . An exception occurs in glacial terrains where many rivers discharging from glaciated regions have chemical w eathering rates that are higher than the global average despite their low temperatures ( Sharp et al., 1995 ; White and Blum, 1995 ; Gaillardet et al., 1999 ; Nezat et al., 2001 ; Jacobson et al., 2003 ; Gislason et al., 2009 ) . These higher rates are attributed to m echanical weathering of bedrock by glaciers , which produce s sedimentary material with high surface area that is readily susceptible to chemical weathering ( Petrovich, 1981 ; Gaillardet et al., 1999 ) . Given that chemical weathering is t he p rimary long term sink for atmospheric CO 2 ( Berner et al., 1983 ; Berner and Berner, 1997 ) , this relationship between mechanical and chemical weathering suggests glacial processes can modulate climate through impacts on the carbon cycle ( Sharp et al., 1995 ; Tranter, 2003 ) . Weathering of glacially derived sediments also produces dissolved solutes and sediment that affect ocean chemistry and can provide critical nutrients that drive primary productivity ( Martin, 1990 ; Bhatia et al., 2013 ) . Variations in the solute chemi stry of stream water s can provide information about the types of weathering reactions and the extent of weathering with in watersheds . For glacial drainage systems, these variations are primarily att ributed to chemical weathering of calcite, biotite, feldspar, Mg silicates , Fe sulfides and intermediate clay minerals (e.g., Blum et al., 1998 ; Anderson et al., 2000 ) . During early stages of weatheri ng, glacial stream solutes are likely to be dominated by carbonate ( Blum et al., 1998 ; Jacobson et al., 2002 ; Wimpenny et al., 2010 ) and sulfide minerals ( Anderson et

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12 al., 1997 ; Anderson et al., 2000 ) that weather more readily than silicate minerals. For example , calcite weatheri ng dominates solute concentrations in Himalayan watersheds that experience chemical weathering conditions similar to conditions in regions influenced by continental ice sheets ( Blum et al., 1998 ; Jacobson and Blum, 2000 ; Jacobson et al., 2002 ; Quade et al., 2003 ) . The timescale over which calcite weathering dominates across different glacial environments is poorly defined ( Blum et al., 1998 ; Gaillardet et al., 1999 ; White et al., 1999 ; English et al., 2000 ) , but is estimated to be on the order of tens of thousa nds of years in the Raikhot watershed, Himalayas, by Jacobson et al. (2002 ) . Carbonate weathering reactions contribute excess Ca 2+ (and sometimes Mg 2+ ) and HCO 3 to streams. Discharge from ter rains primarily weathering carbonate minerals contains little Si relative to other ions. In addition to solute chemistry, radi o genic isotopes also vary with weathering in glacial terrains. S tudies by Blum, Erel, Harlavan and colleagues ( Blum and Erel, 1997 ; Harlavan et al., 1998 ; Harlavan and Erel, 2002 ; Harlavan et al., 2009 ) exploit the incongruent weathering behavior of silicate rocks . Inconguent weathering in these systems is defined as the partial dissolution of particular mineral phases and preferential leaching from defect sites damaged during radioactive decay produce weathering solutions that are more radiogenic in terms of Pb and Sr isotopes than the parent bedrock . These studies used laboratory techniques to leach glacial chronosequences . They demonstrate d that early stages of weathe ring remove radiogenic components during incongruent weathering and as weathering continues , the isotopic composition of the weathering solution begins to approach the composition of the source rock , which is a signal of congruent weathering ( Blum and Erel, 1995 ;

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13 Blum and Erel, 1997 ; Harlavan et al., 1998 ; Harlavan and Erel, 2002 ; Ha rlavan et al., 2009 ) . Laurentide glacial sediments were found to reach congruent silicate weathering of Pb isotopes in ~ 100 300 ky following deglaciation in laboratory leaching experiments ( Harlavan et al., 1998 , 2009 ) . The i ncongruent behavior of the Sr Rb system depend s on different minerals than the Pb isotope system and thus reach congruent w eathering over different lengths of time . For Sr isotopes , the bulk soil and soil leachate approach congruent weathering within ~20 ky ( Blu m and Erel, 1997 ) . While leaching experiments provide important insight s into the process of incongruent weathering, weathering rates and intensities , and variations in weathering in glacial environments, few studies have tried to apply these types of studies in field settings, using stream samples to monitor the composition of the weathering solutions in place of leachates and stream bedload instead of the moraine soils . One of the few field based studies which uses this technique was conducted by Anderson et al. (2000 ) , where they compar e hydrogeochemistry of wate r versus bedload sediments along ~4 km of an Alaskan proglacial stream, and their results demonstrate small decreases in 87 Sr/ 86 Sr and carbonate/sulfide weathering products along its length. One implication of incongruent weathering studies is tha t chemical weathering in glacial environments is likely to transport solutions with radiogenic Sr and Pb to the oceans ( von Blanckenburg and Nägler, 2001 ) . Previous studies ha ve used continentally derived Pb isotopes preserved in deep sea cores to identify glacial interglacial variations in weathering ( Harlavan et al., 1998 ; Foster and Vance, 2006 ; Kurzweil et al., 2010 ; Crocket et al., 2012 ) . These Pb isotopes are ideal tracers of local continental weathering fluxes due to the short oceanic residence time of Pb; however, studies of

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14 modern processes are limited by contamination from anthropogenic Pb ( Rosman et al., 1993 ; Rosman et al., 1994 ) . In contrast, Sr isotopes can be used to study weathering in modern glacial environments, but they are less useful for studying records of weathering pres erved in marine sediments due to the ir long oceanic residence time (several millions of years) and the resulting homogeneous isotopic distribution in seawater. Glacial discharge currently only represent s ~1% of worldwide stream discharge ( Tr anter, 2003 ) ; however, glacial discharge worldwide is rising and modeling work estimates that glacial contributions may have been as high as 18% of total global discharge following the last glacial maximum at ~12 k a ( Jones et al., 2002 ) . Considering discharge from modern continental glaciers, Greenland is particularly significant because it curre ntly provides ~600 times more discharge to the ocean than Antarctica , despite the fact that the Greenland Ice Sheet (GIS) only represents 8% of global ice coverage ( Jacobs et al., 1992 ; Oerlemans, 1993 ; Jones et al., 2002 ; Tranter, 2003 ) . Because d ischarge is positively correlated with weathering rates ( Anderson et al., 1997 ; Gaillardet et al., 1999 ) , Greenland waters are likely to supply important levels of solutes to the ocean . T oday t he west coast of Green land is estimated to discharge 10 200 t k m 2 yr 1 of glacially derived sediments and solutes to the ocean ( Hasholt, 2003 ) . Much of this discharge is from proglacial str eams, which are directly connected to the GIS and carry large amounts of rock flour relative to other water sources, especially during maximum flow in the summer melt season ( Church and Ryder, 1972 ; McGrath et al., 2010 ; Storms et al., 2012 ) . For example, the proglacial sediment load to the Kangerlussuaq f jord , western Greenland averaged 744 t k m 2 y 1 from 2007 to 2010 ( Hasholt et al., 2013 ) . An

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15 additional sourc e of solutes from Greenland comes from deglaciated watersheds that are separated from the GIS drainages by topographic divides and instead drain annual precipitation , and to a lesser extent, permafrost melt . These watersheds do not contribute substantially to fluxes of suspended sediment, which tends to be trapped in lakes, but they may play an important role in the continental solute flux. Solute concentrations are higher in deglacial watersheds than proglacial systems (Wimpenny et al. 2010). T hese deglaci al watersheds have not been studied as extensively as proglacial systems , perhaps because deglacial discharge does not directly impact sea level , although they contribute solutes to the oceans . D ischarge per area from deglacial catchments is estimated to r epresent about half of the total runoff from western Greenland according to model results ( Mernild et al., 2010 ) . S tud ies of discharge from the proglacial Watson River at Kangerlussuaq also calculated a similar volume of annual discharge per area as the deglacial Pisissarfik watershed NW of Kangerlussuaq ( Helweg et al., 2004 ; McGrath et al., 2010 ; Bartholomew et al., 2011 ) . Considering similar ities in discharge but likely elevated solute concentrations of the deglaciated watersheds, it is critical to understand the ir controls on water compositions and fluxes for estimates of impact of retreating continental glaciers on seawater chemical and rad iogenic isotopic composition . In this study I evaluate the impact of exposure age and annual precipitation on flux es of ions and isotopes to the oceans from deglaciated watersheds by analyzing the geochemistry of solutes across a transect of four deglacia ted watersheds that extend from Sisimiut, Greenland on the coast to the Kangerlussuaq area located approximately 25 km from the edge of the GIS. This transect covers a gradient from elevated

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16 precipitation and older moraines near the coast to desert like co nditions and younger moraines near the ice sheet with small variation in temperature. I analyze the major ion chemistry of these deglacial watersheds and apply thermodynamic modeling to the data to understand saturation states of the water with respect to a suite of minerals . I also compare the 87 Sr /86 Sr ratio of stream waters and bedload sediments from one coastal and one inland watershed to evaluate the intensity of weathering in these end member environments . Finally, I discuss the impact of exposure tim e and climatic conditions on weathering and solute transport in these deglaciated systems .

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17 CHAPTER 2 SITE DESCRIPTION This study focuses on four watersheds that create a transect from the coast near Sisimiut (66.9389° N, 53.6722° W) inland towards Kangerl ussuaq (67.0086° N, 50.6892° W), Greenland. This area of western Greenland represents the widest exposed portion of Greenland, making it an ideal place to study deglacial weathering. Four separate watersheds, referred to as Sisimiut, Nerumaq, Qorlortoq, an d Lake Helen, were sampled (Figure 2 1 and Table 2 1 ). The coastal watersheds (Sisimiut and Nerumaq) experience slightly warmer mean annual temperatures ( 3.9° C) than the inland watersheds (Kangerlussuaq and Lake Helen) ( 5.7° C) ( Cappelen et al., 2001 ; Aebly and Fritz, 2009 ; Leng et al., 2012 ) , but a more critical distinction is the amount of effective preci pitation (precipitation minus evapotranspiration). Sisimiut receives ~300 mm of annual precipitation and loses ~150 mm to evapotranspiration annually, resulting in a net positive water balance of 150 mm ( Hasholt and Søgaard, 1978 ; Harper et al., 2012 ) . In contrast, Kangerlussuaq receives ~150 mm of precipitation annually and loses ~300 m m annually through evapotranspiration for a negative water balance of 150 mm ( Hasholt and Søgaard, 1978 ; Ae bly and Fritz, 2009 ) . The boundary between positive and negative water balances occurs at approximately 52°W , which lies between the Nerumaq and Qorlortoq watersheds ( Anderson et al., 2001 ) (Figure 2 1). Although Wimpenny et al. (2010) published data for a few samples taken from deglacial streams feeding into the Watson River (near Kangerlussuaq) , my study is the first to collect data from multiple deglaciated systems. Much of the previous work on deglacial systems focused on the chemistry of deglaciated lakes in the area. Due to t he negat ive water balance , s everal

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18 inland lakes are , elevated alkalinity ( Anderson et al ., 2001 ; Leng and Anderson, 2003 ) and s table deuterium and oxygen 18 isotope ratios that record increased evaporation inland ( Leng and And erson, 2003 ) (Figure A 1) . Anderson et al. (2001 ) foun d that the water chemistry in these saline lakes was dominated by Na + and HCO 3 + CO 3 2 , and Mg 2+ and HCO 3 + CO 3 2 , which resulted from weathering reactions and eolian inputs . The hydrochemistry of the dilute lakes were more variable than the saline lakes . The four deglacial watersheds included in this study represent a temporal transect of ice sheet retreat. The GIS extended to the continental shelf during the last glacial maximum 21 ka ( Yokoyama et al., 2000 ; Simpson et al., 2009 ) and moved to its current position ~170 km inland through a series of retreats and advances . Th e overall retreat resulted in sequentially younger exposure ages for the four sampled watersheds. The Sisimiut watershed was deglaciated ~10.4 ka based on peat carbon dates ( Kelly, 1979 ) ( compiled Rinterknecht et al., 2009 ) , a result supported by GIS models ( Bennike and Björck, 2002 ; Simpson et al., 2009 ; Levy et al., 2012 ) (Figure 2 1). Nerumaq is located ~30 km east of the Sisimiut watershed and separated from the Sisimiut watershed by a moraine dated 9.9 ka (van Tatenhove et al., 1996). Qorlortoq is ~60 km east of the Nerumaq watershed and the Lake Helen watershed is ~20 km east of the Qorlortoq watershed. Both the Qorlortoq and Lake Helen watershed s are located between Umivit Keglen moraines dated 7.3 ka ( van Tatenhove et al., 1996 ) and the Fjord moraines dated 8.5 ka ( after Weidick, 1972 ; Levy et al., 2012 ) . The trend of decreasing moraine and exposure ages from the coast to the ice sheet is well defined, but the exact exposure age for each locat ion is not. Therefore, I will focus on relative

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19 differences in exposure age, and will compare results between coastal watershed (Sisimiut and Nerumaq) that have been exposed ~ 2 3 ky longer than inland watersheds (Qorlortoq and Lake Helen). Western Greenlan crustal material preserved as part of the greater Precambrian shield ( Escher and Watt, 1976 ; van Gool et al., 2002 ; Colville et al., 2011 ; Harper et al., 2012 ) . Local bedrock was deformed during several orogenic events in the Paleoproterozoic that produced high grade metamorphism ( Kalsbeek et al., 1987 ) . Bedrock in the inland region has been mapped as Archean gneiss ( Escher and Watt, 1976 ; van Gool et al., 2002 ) and ( Wimpenny et al., 2010 ; Wimpenny et al., 2011 ) . In the coastal Sisimiut region, the bedrock is again predominantly Archean gneiss , but it includes charnockite series rocks with calc alkaline intrusions that are unique to the area ( van Gool et al., 2002 ) . Broadly, the dominant rock forming minerals i n both region s are feldspar and quartz with minor biotite, amphibole, pyroxene, apatite, and epidote ( Mowatt, 1994 ) . These minerals are likely to control the weathering products and solutes within each of the four studied watersheds.

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20 Figure 2 1 . Sample Locations. A. Locations of the Sis i miut, Nerumaq, Qorlortoq and Lake Helen watersheds and sample sites in western Greenland. Navy blue dashed lines represent contours of the ages and locations of mapped moraines compiled by Levy et al. (2012) from ( Rinterknecht et al., 2009; TenBrink, 1975; van Tatenhove et al., 1996; Weidick, 1972). The dashed and dotted orange line represents the boundary between the region with a positive water balance to the west and a negative water balance to the east from Ande rson et al. (2001). Sample locations for B. Sisimiut watershed (n=17), C. Nerumaq, Greenland watershed (n=22), D. Qorlortoq watershed (n= 19), and E. Lake Helen watershed (n=15). Samples were collected from each of the Lake Helen watershed locations three times over the 2013 field season; on June 9th, July 12th, and July 28th.

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21 Table 2 1. Sample site location and collection date s . Coastal Sample ID Latitude °N Longitude °W Collection date Inland Sample ID Latitude °N Longitude °W Collection date Sisimiut Qorlortoq S1 M1 66.95085 53.54325 6/18/2013 Q1 T1 1 67.03016 51.28801 7/19/2013 S1 M2 66.94306 53.62503 6/20/2013 Q1 T1 2 67.033 51.28466 7/19/2013 S1 T1 1 66.93484 53.52922 6/17/2013 Q1 T1 3 67.0403 51.31 7/19/2013 S1 T1 2 66.9441 53.47088 6/17/2013 Q1 T1 4 67.03957 51.34821 7/20/2013 S1 T2 1 66.9501 53.45262 6/18/2013 Q1 T2 1 67.0525 51.33503 7/20/2013 S1 T2 2 66.94454 53.47012 6/18/2013 Q1 T2 2 67.04418 51.34759 7/20/2013 S1 T3 1 66.95152 53.4856 6/18/2013 Q1 T3 1 67.05476 51.38103 7/20/2013 S1 T4 1 66.93703 53.53439 6/20/2013 Q1 T3 2 67.06303 51.33403 7/20/2013 S1 T4 2 66.93952 53.57086 6/20/2013 Q1 T3 3 67.05385 51.33858 7/20/2013 S1 T5 1 66.97227 53.4867 6/23/2013 Q1 M1 67.03515 51.36023 7/22/2013 S1 T5 2 66.96494 53.51175 6/23/2013 Q1 M2 67.02866 51.36569 7/22/2013 S1 T5 3 66.95197 53.5625 6/23/2013 Q1 M3 67.01822 51.43164 7/21/2013 S2 M1 66.96913 53.70578 6/19/2013 Q1 M4 67.0089 51.46678 7/21/2013 S3 M1 66.96763 53.67804 6/19/2013 Q2 T1 1 67.0107 51.36922 7/23/2013 S3 M2 66.9641 53.67577 6/19/2013 Q2 T1 2 67.01105 51.37634 7/23/2013 S3 M3 66.95554 53.69738 6/19/2013 Q2 T2 1 66.99643 51.38151 7/23/2013 S3 M4 66.95101 53.70235 6/20/2013 Q2 T2 2 67.00652 51.37966 7/23/2013 Nerumaq Q2 M1 67.01581 51.39448 7/21/2013 N1 M1 67.01157 52.86885 6/30/2013 Q2 M2 67.00553 51.45964 7/21/2013 N1 M2 67.0049 52.9128 6/30/2013 Lake Helen N1 M3 67.00509 52.96457 7/2/2013 DG 8 1 1 67.02335 50.82552 6/9/2013 N1 M4 67.01607 53.03032 7/1/2013 DG 8 2 1 67.01692 50.8562 6/9/2013 N1 M5 67.01176 53.08467 7/1/2013 DG 8 3 1 67.00815 50.87608 6/9/2013 N1 T1 1 67.02875 52.75915 6/26/2013 DG 8 4 1 66.98958 50.93108 6/11/2013 N1 T1 2 67.01218 52.83547 6/27/2013 DG 8 5 1 66.96861 50.95475 6/10/2013 N1 T1 3 67.0116 52.86325 6/27/2013 DG 8 1 2 67.92341 50.82575 7/12/2013 N1 T2 1 67.02753 52.79428 6/26/2013 DG 8 2 2 67.0156 50.86085 7/12/2013 N1 T2 2 67.02617 52.79885 6/26/2013 DG 8 3 2 67.00816 50.87609 7/12/2013 N1 T2 3 67.0186 52.82721 6/27/2013 DG 8 4 2 67.98965 50.93127 7/12/2013 N1 T2 4 67.0127 52.86063 6/27/2013 DG 8 5 2 66.96866 50.95468 7/12/2013 N1 T3 1 67.01449 52.86322 6/30/2013 DG 8 1 3 67.02341 50.82575 7/28/2013 N1 T3 2 67.01196 52.86728 6/30/2013 DG 8 2 3 67.0156 50.86085 7/28/2013 N1 T4 1 67.02779 52.95046 7/2/2013 DG 8 3 3 67.00816 50.87609 7/28/2013 N1 T4 2 67.01479 53.09164 7/1/2013 DG 8 4 3 66.98943 50.93122 7/28/2013 N1 T5 1 67.01594 53.01915 7/1/2013 DG 8 5 3 66.96864 50.95463 7/28/2013 N1 T6 1 67.01524 52.94192 7/2/2013 N1 T6 2 67.00748 52.96285 7/2/2013 N1 T7 1 67.00353 52.91473 7/3/2013 N1 T8 1 67.00338 52.91604 7/3/2013 N1 T9 1 66.99841 52.94772 7/3/2013 * Samples are designated AX BY, where A is the location (Sisimiut, Nerumaq, Qorlortoq, or Lake Helen) abbreviated as the first letter (Lake Helen is an exception to this and referred to as ) , X is the number of the drainage basin in the location, B represents a main channel (M) or tributary (T) designation, and Y represents the positions from the headw aters in ascending order

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22 CHAPTER 3 METHODS Field Sampling Procedures Water and sediment samples for this project were collected from June 9 to July 23, 2013 and represent a subset of samples from a larger project . I dentical procedures were employed at all sampling sites. Water s ampling consisted of pumping water through an overflow cup on the bank s of stream s using a Geotech II 12 V peristaltic pump and tygon tubing that was placed near the center of the channel. Fie ld parameters, including water temperature, pH, dissolved oxygen (DO), specific conductivity (SpC), and oxidation reduction potenti al (ORP), were measured using an YSI Pro Plus multiparameter instrument with the sonde installed in the overflow cup (Appendi x A) . The YSI was calibrated daily and showed little drift between calibrations . Water was filtered through a 0.45 µm trace metal grade canister filter and samples were collected after f ield parameters had stabilized. Filtered samples were collected in a v ariety of bottle type s and preserved with various preservatives depending on the analyte to be measured. Sample bottles were triple rinsed with s ample water prior to collection. Samples for radiogenic isotopes , cations, and trace elements were collected in acid washed HDPE bottles and acidified in the field to pH < 2 with optima nitric acid (HNO 3 ). Radiogenic isotope samples were collected in either 125 or 250 mL bottles , and cations/trace elements were collected in 20 mL bottles . Samples for analyses of 18 O and D values of the water were collected in 1 mL glass vials with no head space and gas tight rubber septa tops . Filtered samples were collected in 60 mL HDPE bottles for measurements of total alkalinity and were titrated within 24 hrs according to th e Gran method using 15 mL samp le and 0.1 N hydrochloric acid. I consider the measured

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23 alkalinity to be carbonate alkalinity assuming only small concentrations of other weak acids (e.g., borate, bisulfide, organic anions etc. ) ( Drever, 1997 ) . Silica concentrations were measured within 30 days of collection from aliquots remaining from the alkalinity titrations using a Hach DR/890 Portable C olorimeter instrument according to the Heteropoly Blue Method optimized for low concentrations (0 to 1.60 mg/L). Samples above 1.6mg/l were diluted and re analyzed. All water samples were kept chilled in the field and refrigerated continuously in the labor atory prior to analysis . All samples were shipped chilled to University of Florida (UF) by air within one month of field collection. Stream bedload sediment samples were collected using sterile plastic trowels or gloved hands. Care was taken to maintain o riginal grain size distribution by collecting large samples and minimizing disturbance during sampling. Sediments were stored at 4°C in whirlpak bags until processed. Initial p rocessing involved freeze drying the samples at UF in a 60°C oven. Water Analyses All laboratory based analyses were performed in the Department of Geological Sciences at UF. Major ion concentrations (including Ca 2+ , K + , Na + , Mg + , SO 4 2 , and Cl ) were analyzed using a Dionex Model 500 D X Ion Chromatograph and in house multi elem ent standards. Samples did not require dilution before analysis. Measurement precision was <5.0% based on duplicate standards runs every five samples and standard analyses. Charge balance errors were <10% in 85% of the samples and all errors were <20% . Min or elemental concentrations of Al, Mn, Fe, Sr, Ba, Nd, and Pb were measured using a Thermo Scientific Element 2 HR ICP MS. Samples were diluted 1:1 with 5% HNO3 spiked with 8 parts per billion (ppb) rhenium (Re) and rhodium (Rh) and analyzed using in house standards. Long term m easurement reproducibility was

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24 checked against external Canadian riv er water standard SLRS4 . R elative standard error between repeated measurements of SLRS4 remained under 8% for all elements. Oxygen isotopes ( 18 O) and deuterium iso topes ( D) were analyzed using a Picarro L2120 I Isotopic Liquid Water & Certified Continuous Water Vapor Analyzer coupled with a Picarro A0211 High Precision Vaporizer and a CTC HTS PAL autosampler. = (R sample R standard )/R standard *1000 where R is the 2 H/ 1 H or 18 O/ 16 O ratio reported relative to Vienna Standard Mean Ocean Water ( VSMOW ) . Repeated measurements of 20 samples of a single aliquot of deionized water and 0.81 for 18 O and D respectively. Aliquots of water collected for radiogenic isotope analyses were transferred to clean Teflon beakers and dried in a class 1000 clean laboratory at UF . Aqua regia was added to the beaker 2 mL at a time to oxidize any organic matter and the process was repeated, drying down the solution between additions, until reactions ceased. Sr was isolated using 100 µL Eichrom Technologies (50 100 µm) Sr spec resin according to standard column chemistry procedures ( Pin and Bassin, 1992 ) for subsequent analyses of 87 Sr/ 86 Sr ratios. The separated Sr was loaded on degassed tungsten fil aments and 87 Sr/ 86 Sr isotopes were measured on a Micromass Sector 54 multi collector thermal ionization mass spectrometer (TIMS) in dynamic mode. Two hundred ratios were collected at an intensity of 1.5 V 88 Sr. 87 Sr/ 86 Sr ratios were normalized to 86 Sr/ 88 Sr = 0.1194. Repeat analyses of NBS 987 yield ed a value of 0.71025 (+/ external reproducibility). P rocedural blanks created by drying 250 mL 4x deionized water, treat ing it with the same acid used to treat the samples , and separating Sr

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25 through column chemistry procedures identical to those used for the samples produced b lanks ranged from 20 250 pg Sr. Sediment Analyses Dried sediments were sieved to isolate the <2.0 mm size fraction and ground with a clean mortar and pestle. Loss on ignition wa s calculated for ~3 g subsamples weighed before and after heating in a 550°C oven for 3.0 hrs. All samples were duplicated and agreed within <10%. Homogenous, ground 0.05 g samples were dissolved on a hotplate in capped Teflon beakers in a 3:1 solution of HNO 3 :HF , dried down and brought up in optima HCl. This process was repeated until samples were completely dissolved, which required approximately three repetitions . Saturation Indices Saturation indices (SI = log(IAP/Keq ) ) where IAP is the ion activity product and Keq is the equilibrium product) of a suite of minerals were estimated for each stream water sample using PHREEQc software and the PHREEQc database ( Parkhurst and Appelo, 1999 ) . Input parameters included total alkalinity, pH, tempe rature , and concentrations of Ca 2+ , K + , Na + , Mg + , SO 4 2 , Cl , Si, Al, Mn, Fe, Sr, Ba, Nd, and Pb (Appendix Tables, B ,C,D,E (1 3) ).

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26 CHAPTER 4 RESULTS Field parameters (Specific Conductivity , pH , and Dissolved Oxygen ) Water from the c oastal watersheds (Sisimuit and Nerumaq) are more dilute than inland watersheds ( Tables ( B E ) 1 ) . The lowest specific co nductivity (18.9 µs/cm) occurs near snowmelt input in the Nerumaq watershed (N1 T2 1) while Sisimiut has the lowest average specific conductivit y for a w atershed with an average value of 48.26 µs/cm (ranging from 31.2 68.4 µs/cm). The highest average specific conductivit y for a watershed (300.9 µs/cm) occurs in the Qorlortoq watershed , which is the location farthest from the coast/fjords . This watershed al so show s the greatest range in conductivity (105.0 1632.0 µs/cm) and the highest average water temperature of 15.3°C (ranging from 4.8 21.1°C) . The other watersheds have similar average water temperatures, averaging 7.7 °C in Sisimiut (ranging from 8.2 11.0 °C ), 8.7 °C in Nerumaq (ranging from 0.6 16.5°C), and 7.8°C in Lake Helen (ranging from 3.1 15 .0 °C) Specific conductivities increase downstream in all streams with the exception of the Nerumaq main channel and tributary one in Qorlortoq, in which specific conductivity decreases . Spec ific conductivity also increased in the Lake Helen w atershed over the course of the sampling season from an average of 98.7 for 6/9/2013 to 201.1 µs/cm for 7/28/2013. Most sampled deglacial stream waters exhibit pH values that a re near neutral. The coastal watersheds are slightly more acidic than the i nland watersheds . The average pH value for Sisimiut is 7.07 (range 6.45 7.31), for Nerumaq is 7.18 (range 6.3 7.9), for Qorlortoq is 8.24 (range 6.68 9.57), and for Lake Helen is 7. 45 (range 6.86 8.09).

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27 The average dissolved oxygen (DO) concentration is 7. 7 mg/l (range 2.8 11.0 ) for Sisimiut, 11.1 mg/l (range 8.8 12.9 ) for Nerumaq, 9.8 mg/l (range 8.0 11.4 ) for Qorlortoq, and 10.6 mg/l (range 8.8 11.7 ) for Lake Helen . DO in % saturation is 95% (range 87.7 101 ) for Sisimiut, 94.7% (range 85.5 107.3 ) for Nerumaq, 97.9% (range 79.4 121.3 ) for Qorlortoq, and 89.3% (range 74.5 102.4 ) for Lake Helen . Major element and Sr concentrations The range of compositions of major ele ments differ slightly between cations and anions. Cation concentrations in water samples fall within a small range of compositions, with roughly equal parts Mg 2+ , Ca 2+ , and (Na + +K + ) ions (Figure 4 1 A ). The Lake Helen watershed has slightly greater proport ion of Mg 2+ than other watersheds , and Sisimiut has slightly higher (Na+K) on average . Anion concentrations are more variable than cation concentrations, particularly for sulfate and alkalinity. Sulfate is the dominant anion in the Nerumaq watershed while bicarbonate (plotted as alkalinity) is the dominant anion in the Qorlortoq and Lake Helen watershed s (Figure 4 1 B). The relative fractions of sulfate and alkalinity in t he Sisimuit watershed are intermediate between the Nerumaq and Qorlortoq watersheds. All water samples have higher Na+K and Ca + Mg concentrations than silica (Figure 4 1 C). Inland deglacial waters have <1 0 % silica and in many cases < 5%. Coastal watersheds have higher proportions of Si than inland watersheds . Sodium concentrations in the w aters correlate well with Cl concentrations ( Figure 4 2 and Table 4 1) . Regression analyses of Na + and Cl concentrations indicate slopes of 1.25 (p <0.0001 ) and 1.90 (p <0.0001 ) from the Sisimiut and Nerumaq watersheds respectively and 0.84 (p <0.0001 ) and 0.76 (p <0.0001 ) from the Qorlortoq and Lake Helen watersheds respectively . These slopes reflect the average N a + /Cl ratios for the

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28 watersheds . The values from Sisimiut and Nerumaq watersheds are elevated over the seawater ratio of 0.86 for Na + /Cl ( Keene et al. , 1986 ) (Figure 4 2 B ) , but ratios for Qorlortoq and Lake Helen watersheds are similar to the seawater ratio ( e.g. Keene et al., 1986 ) (Figure 4 2 A ). The sample collected near snowmelt in Nerumaq (N1 T2 1) has a Na + /Cl ratio o f 0.64 , slightly lower than the seawater ratio. Regression analyses of SO 4 2 Cl concentrations indicate that all watersheds have SO 4 2 /Cl ratios that are elevated relative to the seawater SO 4 2 /Cl ratio of 0.14 ( Kroopnick, 1977 ) (Figure 4 3 and Table 4 1) . L inear regressions indicate good correlations between SO 4 2 and Cl in the Nerumaq and Lake Helen watersheds, but not in the Sisimiut and Qorl ortoq watersheds. Regression analyses of the SO 4 2 Cl correlations reveal that average molar SO 4 2 /Cl ratios are 7.57 (p= 0.0007 ) for Nerumaq and 0.38 for Lake Helen (p< 0.0001 ) (Figure 4 3 ). The excess SO 4 2 compared with seawater Cl concentrations is greatest in the Nerumaq and Qorlortoq watersheds , which also exhibit the greatest range in sulfate ion concentrations (Figure 4 3 ). A verage silica concentrations are elevated at the Sisimiut (37.9 µM) and Nerumaq (55.0 µM) watersheds over the Qorlorto q (18.2 µM) and Lake Helen (27.5 µM) watersheds, despite having lower specific conductivities and major ion concentrations (Figure 4 4 ). Regression correlations are not statistically significant for Si and Ca2+ concentrations in any of the watersheds. None theless, each watershed has distinct ranges of concentrations for Si and Ca. The Inland watershed samples exhibit higher Ca 2+ and lower silica concentrations relative to the coastal watersheds. Unlike the poor Si Ca correlations, Ca correlates well with Sr concentrations for all watersheds (p< 0.0001 for all watersheds) (Figure 4 5 ) (Table 4 1) . The slopes of thes e

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29 regression analyses are similar in water s from the Sisimiut and Nerumaq watersheds with average Ca/Sr molar ratios of 0.062 x 10 3 and 0.16 x 10 3 , respectively. Water s from the Lake Helen and Qorlortoq watershed s ha ve a Ca/Sr ratio of ~ 0.55 x 10 3 , elevated by ~9 times over Sis i miut and ~3 times over Nerumaq . These results reflects a n increase in the Ca/Sr from coastal to inland watersheds . Satu ration Indices Determination of over or undersaturat ion with respect to a mineral indicates whether a mineral is thermodynamically favored to precipitate or dissolve in solution, but does not provide any information regarding dissolution rates or the flux of weathered solutes. Saturation states of a range of minerals are similar for each watershed, when averaged over all the sam ples within that watershed (Figure 4 6 ), although there are subtle differences in the magnitude of over or under saturation. Wate rs in all four watersheds are undersaturated with respect to feldspars, quartz, chlorite, calcite, and barite, and oversaturated with respect to potassium mica, gibbsite, kaolinite and Fe oxides. Quartz and amorphous SiO 2 saturations are slightly closer to equilibrium in coastal than inland watersheds. Some of the largest differences between sites are observed in the saturation state s of chlorite and calcite , which are closer to equilibrium in water s from Qorlortoq and Lak e Helen w atersheds than Sisimuit and Nerumaq watersheds. The inland watersheds are also slightly more oversaturated than coastal watersheds with respect to various Fe oxides. Radiogenic Sr T he Nerumaq and Qorlortoq water samples exhibit dissolved Sr isotop e ratios that are consistently more radiogenic than values for the corresponding bedload sediment (Figure 4 7 ). Dissolved 87 Sr / 86 Sr in Nerumaq and Qorlortoq watersheds

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30 average 0.713 and 0.732 respectively, while the corresponding bedload values average 0.7 08 and 0.714. The difference between the isotopic ratio of water and bedload samples in Qorlortoq is 0.018 , or about three times higher than the value of 0.005 found in the Nerumaq watershed. Differences between bedload and water as well as between sites a re statisti cally significant ( p < 0.000 1 ) based on test. 87 Sr/ 86 Sr values for waters at Nerumaq and Qorlortoq correlate well with Ca/Sr ion ratios (Figure 4 8 ) . Linear regression analyses show that the slope in Nerumaq (0.017 , p < 0.0001 ) is ~1/2 the slope in Qorlortoq (0.040 , p=0.0032 ). 95% confidence intervals for Nerumaq and Qorlortoq regressional analyses encompass seawater composition s , where 87 Sr/ 86 Sr is 0.7092 and Ca/Sr is 0.118 .

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31 Figure 4 1 . Major ion ternary plot s showing ion proportions in all watersheds (Drever, 1997). A. Major cation proportions in % milliequivalents . B. Major anion proportions in % milliequivalents . C. Relative K + Na, Ca + Mg, and silica ion proportions in % millimoles . Solid black oval design ates approximate Russell Glacier sub glacial water ( Graly et al., 2014 ) , dashed oval approximates Gangtori, Nepal proglacial water ( Singh et al., 2012 ) , greyed long dashed oval approximates Raikhot, Pakistan proglacial water ( Blum et al., 1998 ) , and the dotted polygon represents approximate weathering proportions of K feldspar and amphiboles to clay.

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32 Figure 4 2 . Na + versus Cl molar concentrations. Seawater relat ionship is plotted as dotted line (Keene et al., 1986). A. All Locations. B. Inset of Sisimiut and Nerumaq. Errors are smaller than data points.

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33 Figure 4 3 . SO 4 2 versus Cl molar concentrations. Seawater relationship is plotted as dotted line ( Morris and Riley, 1966 ) . Errors are smaller than data points.

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34 Figure 4 4. S ilica versus Ca 2+ molar concentrations. Dotted line s represents ion ratios in the feldspar weatheri ng equation (E q uation 5 1 ). Errors are smaller than data points.

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35 Figure 4 5 . Dissolved Ca 2+ versus Sr. Lines are linear regressions through the data for each watershed. Resulting slopes are average molar ratios times 1000. Silicate and calcium concentration trends from ( Jacobson et al., 2002 ) are shown as dashed and dotted lines for comparison . Errors are smaller than data points.

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36 Figure 4 6 . Saturation indices of key minerals plotted by watershed. The data points represent the mean indices of all of the samples from each watershed and the error bars represent 2 standard deviations of the data within each watershed.

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3 7 Figure 4 7 . 87 Sr /86 Sr ratios for bedload fractions (< 2mm )and wat ers from Nerumaq (n=21) and Qorlortoq (n=6). The average 87 Sr /86 Sr ratio for Nerumaq bedload is 0.708 and water is 0.713. The average 87 Sr /86 Sr ratio for Qorlortoq bedload is 0.714 and water is 0.732. Mean difference between bedload and water is 0.005 in Nerumaq and 0.018 in Qorlortoq. 87 Sr /86 Sr errors are smaller than data points.

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38 Figure 4 8 . 87 Sr /86 Sr versus Ca/Sr. Lines are linear regression s through the data for each watershed. Q orlortoq Y intercept= .7073 Ner uma q Y i ntercept= . 7081 Errors are smaller than data points.

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39 Table 4 1. Summary of major Ion and Strontium concentration with distance from the coast. Poor correlations are not plotted on figures (P>.005) . Watershed Distance from Coast Regression Na/Cl (mmol/mmol) SO4/Cl (mmol/mmol) Ca/Sr (mmol/nmol) Sisimiut 13 Km Value 1.25 0.069 0.062 r^2 0.70 0.00051 0.64 p value <0.0001 0.93 0.0001 Nerumaq 45 Km Value 1.9 7.57 0.16 r^2 0.83 0.41 0.82 p value <0.0001 0.0007 <0.0001 Qorlortoq 110 km Value 0.84 0.27 0.56 r^2 0.98 0.08 0.91 p value <0.0001 0.26 <0.0001 Lake Helen 130 km Value 0.76 0.38 0.55 r^2 0.98 0.95 0.98 p value <0.0001 <0.0001 <0.0001 Seawater 0.86 * 0.14 ** * ( Keene et al., 1986 ) ** ( Morris and Riley, 1966 )

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40 CHAPTER 5 DISCUSSION Weathering Mineralogy Major ion chemistry of coastal streams worldwide is influenced both by marine aerosols ( Fitzgerald, 1991 ) and the mineralogy of the underlying bedrock via weathering ( Meybeck, 1987 ; Clow et al., 1996 ) . The major element and ion composition of seawater is well known and thus its contribution to stream water via marine aerosols can be estimated, but the impact of weathering will vary depending on what minerals dissolve or precipitate. For example, cations in rivers traversing granitic terrains tend to be dominated by Na + +K + from the weathering of feldspars, micas, and amphiboles , while rivers flowing through carbonates are dominated by Ca 2+ (e.g. Meybeck, 1987 ; Gislason et al., 1996 ; Gaillardet et al., 1999 ; Galy et al., 1999 ; Chen et al., 2002 ; Han and Liu, 2004 ; Wimpenny et al., 2010 ) . Multiple lines of evidence suggest that coastal watersheds experience more dissolution of silicate and sulfide minerals than the inland watersheds, which have a greater dominance carbonate mineral dissolution. The cation c omposition in Sisimiut waters shows the greatest proportion of (Na + +K + ), while the Lake Helen watershed has the lowest proportion of (Na + +K + ) ions, reflecting a gradient of decreasing silicate dissolution inland from the coast (Figure 4 1 A). Similarly, th e greater proportions of Ca and Mg over silica at inland watersheds reflect a greater contribution of carbonate mineral dissolution inland (Figure 4 1 C). A ll watersheds remain far from the ~50% relative silica concentration that would be expected from wea thering of granitic /gnei ssic bedrock and are thus still weathering as relatively immature systems (Figure 4 1 C). These low silica concentrations may in part indicate precipitation of clay

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41 minerals , a concept that is supported by % Si relative to Na+K and C a+Mg decreas ing downstream in both coastal and inland watersheds. S ilica may be removed from solution by the precipitation of clay minerals, such as kaolinite, which is supersaturated in these waters (Fig. 4 6). Similarly, anions in rivers primarily influe nced by input from atmospheric CO 2 and carbonate dissolution tend to be dominated by bicarbonate ion, while rivers dominated by the oxidation of sulfides tend to have elevated SO 4 2 concentrations ( Sharp et al., 1995 ; Anderson et al., 2000 ) . HCO 3 is more ab undant in Qorlortoq and Lake Helen watersheds than in the Sisimiut and Nerumaq watersheds (Figure 4 1 B), which are dominated by SO 4 2 . These data also indicate carbonate dissolution may be the primary control of major anion compositions in the inland site s, while oxidative dissolution of iron sulfides is the primary control of major anions in the coastal watersheds (Figure 4 1 B). Comparing major ion ratios in these watersheds provides additional information about weathering reactions (Fig. 4 1). Comparis on of ions to Cl concentrations is useful in these settings because no Cl bearing minerals occur in the bedrock, making it conservative in these systems. The negative water balance of the inland watersheds should enhance the concentration of marine aeros ols, but should not modify the ionic ratios. ( Fitzgerald, 1991 ) (Figures 4 2 & 4 3). The observation of excess Na + to Cl compared with the seawater Na + /Cl ratio at Sisimiut and Nerumaq suggests weathering of Na Feldspar (Figure 4 2). Ratios of SO 4 2 /Cl that are elevated in coastal watersheds relative to inland watersheds support greater dissolution of sulfide minerals in coastal watersheds (Figure 4 3).

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42 Ca/Sr and Si/Ca addi tionally help identify ion proportions from carbonate weathering, because high Ca/Sr and low Si/Ca are associated with rivers crossing carbonate terrains or those preferentially influenced by trace carbonate dissolution ( Blum et al., 1998 ; Jacobson et al., 2002 ) . The Ca/Sr molar ratios are 0.06x10 3 and 0.16 x 10 3 in the Sisimiut and Nerumaq watersheds resp ectively. In contrast, the Ca/Sr molar ratios are ~0.55 x 10 3 in the Qorlortoq and Lake Helen watersheds, close to ratios found in weathering solutions dominated by dissolved carbonate minerals (Figure 4 5) ( Blum et al., 1998 ) . These ratios again reflect the transition to a greater contribution from silicate weathering in the coastal wate rsheds. The primary silicate mineral undergoing weathering in western Greenland watersheds is plagioclase (Na,Ca feldspar) based on prior mineralogical descriptions of the region ( Mowatt, 1994 ; Wallroth et al., 2010 ) . Comparison of Si/Ca ratios in solution to that of ideal plagioclase weathering provides information on the potential role of feldspar weathering in coastal ver sus inland watersheds. Plagioclase weathering yields the following products Ca x Na (1 x) Al (1+x) Si (3 x) O 8 +(1+x)CO 2 +(2+2x)H 2 (5 2) xCa 2+ +(1 x)Na + +(3 x)SiO 2 +(1+x)HCO3 +(1+x)Al(OH) 3 where x is the fraction of anorthite versus albite, and Al is assumed t o be conserved as Al hydroxide ( White et al., 2005 ) . Considering equation 5 2, the Si/Ca 2+ ratio would vary from 2:1 if the source material is anorthite to 3:1 if it is albite. Contributions from weathering of microcline (K feldspar: KAlS i 3 O 8 ) would further increase the Si/Ca 2+ ratio, as its crystal structure does not include calcium. Sisimiut waters plot closest to the Si/Ca 2+ ratio expected for dissolution of albite in all the watersheds. In contrast, the

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43 inland sites show Ca 2+ enrichment over silica, reflecting elevated carbonate mineral dissolution (Figure 4 4). The dominance of carbonate weathering in the inland watersheds, as well as the coastal watersheds, is somewhat surprising considering these watersheds drain felsic te rrains. The occurrence of carbonate weathering from felsic terrains is a phenomenon that has previously been documented in proglacial systems in Greenland, the Himalayas, and other alpine glacial settings ( Blum et al., 1998 ; Anderson et al., 2000 ; Jacobson e t al., 2002 ; Wimpenny et al., 2010 ) . For example, Ca 2+ /Sr 2+ ratios range from x 10 3 for calcite rich watersheds to ~0.20 x 10 3 for silicate watersheds in the Raikhot region of the Himalayas in Pakistan ( Blum et al., 1998 ) . This region is underlain by high grade quartzo feldspathic biotite gneisses similar to the Archean gneisses of western Greenland. Raikhot watershed Ca 2+ /Sr 2+ ratios are similar to those found in this study, which increase from 0.062 and 0.160 at coasta l watersheds (Sisimiut and Nerumaq) to 0.550 and 0.560 at inland watersheds (Qorlortoq and Lake Helen). Waters from deglacial watersheds measured in this study plot close to those measured by Wimpenny et al. (2010 ) in deglacial streams of West Greenland, but in general these deglacial systems have a smaller proportion of silica than proglacial waters (Figure 4 1 C). Ion proportions from the deglacial streams plot near wate rs draining Himalayan proglacial streams in Gangtori, Nepal, but with a greater proportion of Na+K than the Himalayan Raikhot watershed (Figure 4 1 C) ( Blum et al., 1998 ; Singh et al., 2012 ) . The observation of sulfide dissolution in the coastal watersheds contrasts with interpretations based on the composition of subglacial waters collected through

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44 boreholes 0 45 km from the edge of the GIS ( Graly et al., 2014 ) . These subglacial waters were found to be SO 4 2 free, an observation that was in terpreted to indicate all sulfide minerals had been weathered from the underlying bedrock. The elevated SO 4 2 relative to Cl in the nearshore deglacial watersheds suggests that sulfides remain reactive in deglacial environments of western Greenland. In ad dition, all four watersheds have DO values that would support oxidation . Lower DO concentrations under the GIS may explain the lack of SO 4 2 in that environment ( Graly et al., 2014 ) D espite being a source of Ca from carbonate mineral dissolution in the deglaciated watersheds, carbonate minerals are not volumetrically significant in the local bedrock. White et al. (20 05 ) near Nuuk, Greenland, an area south of the study transect that is also underlain by Archean gneisses. The overall calcite concentration in Nuuk rock samples was only 0.52 4.64 g/kg; however, c arbonate minerals weather more readily than silicate minerals. Documented rates are~5 7 orders of magnitude faster than plagioclase in neutral waters ( Plummer and Busenberg, 1982 ; Chou et al., 1989 ; Blum, 1994 ; Blum and Stillings, 1995 ; White et al., 1999 ) . Calcite weathering products can therefore be disproportionately represented in weathering solutes, particularly from young watersheds where they have not yet been weathered from e xposed surfaces. Mineral saturation indices modeled for average solute concentrations offer additional support for the differences in mineral dissolution at coastal and inland watersheds (Fig 4 6). Calcite is closer to equilibrium in inland watersheds tha n coastal watersheds, indicating greater active carbonate dissolution (Figure 4 6). In contrast, several silicate minerals, including quartz, amorphous silica, and albite, are

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45 undersaturated along the transect, indicating dissolution within all four waters heds. Overlapping ranges of some values and their standard deviations make it impossible to determine saturation differences between watersheds for some minerals, especially for K feldspar, illite, gibbsite, and kaolinite. Supersaturation of Fe oxide miner als is consistent in all watersheds, and Fe oxide coatings occur on bedload sediments in all streams. The oversaturation of kaolinite in deglacial waters supports clay precipitation, which may reduce silica molar proportions in solution. In summary, inlan d watersheds have greater contribution from carbonate weathering products relative to coastal sites based on higher carbonate ion proportions, lower Si/Sr, elevated Ca/Sr, and increased calcite saturation in solution. However, although silicate contributio ns are greater at coastal watersheds, major ion proportions are still well below those expected from mature granitic weathering reactions. Weathering proportions support the idea that carbonate mineral weathering dominates over silicate weathering products in the inland watersheds, but that all four watersheds experience immature weathering reactions indicative of trace mineral dissolution rather than complete dissolution of felsic bedrock. Chemical Weathering Intensity Given the similarity of the bedrock and moraine material in the four watersheds, the increasing contribution from silicate weathering along the transect reflects the loss of easily weathered components, such as carbonate minerals, due to more extensive wea thering in coastal watersheds than inland watersheds. Similar shifts in the amount of carbonate weathering have been documented in other watersheds overlying granitic bedrock, including watersheds in glaciated regions ( White et al., 1999 ; Jacobson and

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46 Blum, 2000 ; Jacobson et al., 2002 ; Wimpenny et al., 2010 ) . For example, Anderson et al. (2000 ) describe Alaskan proglacial waters that reflect predominately calcite weathering soon after exposure, but where silicate weathering products increase as streamwater interacts with older moraine sediments several kilometers downstream. In laboratory column experiments simulating weathering conditions in Yosemite granitoid terrains, White et al. (1999 ) also found cont ributions from carbonate weathering to decrease over a 1.7 year study period as silicate weathering products simultaneously increased. The intensity of weathering across the four sampled watersheds is also reflected in the difference in Sr isotope ratios o f the stream water and the bedload sediment (Fig. 4 7). As Harlavan, Blum and colleagues demonstrated, young moraine sequences have soil leachates that are more radiogenic that the soil itself, indicating incongruent weathering of biotite (Sr isotopes) and accessory minerals (Pb isotopes), or from extraction of easily weathered radiogenic isotopes in damaged crystal lattice sites ( Blum and Erel, 1997 ; Harlavan et al., 2009 ) . With continued weathering and preferential removal of the radiogenic Sr, weathering solutions approach the 87 Sr/ 86 Sr of the bulk bedload. At this point, the 87 Sr/ 86 Sr composition of the water is controlled by contributions from feldspar, carbonates, micas, epidote, and clay minerals ( Garçon et al., 2014 ) . Strontium isotope ra tios of water from both the Qorlortoq and Nerumaq watersheds are more radiogenic than the associated bedload, and the offset is more pronounced in the Qorlortoq watershed than the Nerumaq watershed (Figure 4 7). The larger offset in Qorlortoq suggests stro nger incongruent weathering and, therefore, less

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47 extensive weathering. Although the offset is smaller overall for Nerumaq samples, the greatest offsets within the Nerumaq watershed occur at the headwaters of tributaries. The headwater soils and bedrock may be less weathered than main channel sediments for a variety of reasons including: lower flow and hence smaller water rock ratios, longer periods of snow cover limiting flow, and more intense mechanical weathering in the elevated locations of the headwater s. In addition, bedload sediments downstream of the headwaters have traveled farther and thus have been more intensely weathered than bedload in the headwaters of the streams. Bedload 87 Sr/ 86 Sr ratios from both watersheds are within the range of values rep orted for stream sediment samples ( 0.70 7 0.71 4) from the western Greenland Nagssugtoqidian Mobile Belt (NMB) ( Colville et al. (2011 ) . The average 87 Sr / 86 Sr bedload value for Qorlortoq (0.708) is slightly higher than the average value for bedload from Nerumaq (0.714), but the 0.006 difference between Qorlortoq and Nerumaq is slightly smaller than the range in NMB bedload 87 Sr / 86 Sr ( 0.00 7) reported by ( Colville et al., 2011 ) , where the stream se diments with the highest and lowest 87 Sr / 86 Sr were both collected from near the Sisimiut watershed. While bedload 87 Sr / 86 Sr is slightly higher in Qorlortoq than Nerumaq, differences in bedload 87 Sr / 86 Sr vary little across the study transect compared with bedrock across western Greenland, which Colville et al. (2011 ) found to vary from 0.70 to >0.80, indicating that lithology across our study transect is homogenous relative to other areas in western Greenland. Because the concentration of Sr is higher in calcite than in silicate minerals, calcite dissolution is likely to have a disproportionate influence on the 87 Sr / 86 Sr ratio of dissolved Sr. Marin e carbonates tend to contribute Sr with lower 87 Sr / 86 Sr ratios

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48 compared with felsic rocks ; however, White et al. (2005 ) found that calcite inclusions in granitoid rocks world wide tend to have higher 87 Sr / 86 Sr than associ ated feldspar minerals. ( Singh et al., 1998 ) also found highly radiogenic Sr (ranging from 0.706 to 0.89 4) in a subset of the metamorphosed calcite from the lesser Himalayas. The linear relationship (regression analyses: p<.0001 for Nerumaq and p< 0.005 for Qorlortoq) between 87 Sr / 86 Sr and Ca/Sr ratios in the watersheds indicates mixing between two endmembers (Figure 4 8). The low 87 Sr/ 86 Sr and low Ca/Sr endmember appears to be sourced from seawater aerosols, with 87 Sr / 86 Sr ratio of 0.70917, but the radiogenic endmember has a different 87 Sr / 86 Sr ratio in the two watersheds. The radiogenic end member has a higher 87 Sr / 86 Sr in the Qorlortoq watershed than the Nerumaq watershe d, which is consistent with a greater contribution from igneous calcites in the inland watersheds. Potential Causes for Differences in Coastal and Inland Weathering The differences in the intensity of weathering documented by the hydrogeochemistry of the sampled watersheds could be caused by initial variations in bedrock composition rather than the extent of weathering; however, the bedrock across inland and coastal r egions is very similar and has similar dominant mineralogies ( Escher and Watt, 1976 ; Kalsbeek et al., 1987 ; Mowatt, 1994 ; van Gool et al., 2002 ; Wallroth et al., 2010 ) . This uniformity was tested more specifically for the study w atersheds through Sr isotopic measurements, which indicated only minor differences. Another possible explanation for the differences in the intensity of weathering between the sites may be differences in exposure ages between the coastal and inland waters heds, although the difference in exposure age is only 2 3 ky based on moraine

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49 ages ( Weidick, 1972 ; Kelly, 1979 ; van Tatenhove et al., 1996 ; Rinterknecht et al., 2009 ; Levy et al., 2012 ) (Figure 2 1). Variations in precipitation also likely contribute to the extent of weathering in different watersheds. Precipitation correlates positively with weathering rates ( White and Blum, 1995 ) , and thus higher precipitation in coastal watersheds contributes to a greater extent of weathering in conjunction with longer exposure age. The negative water balance in the inland watersheds contributes to their elevated solute concentrations, as illustrated by increases in conductivity observed in the Lake Helen watershed throughout the summer (Tables C 1), but also results in lower water rock ratios at inland sites compared to coastal watersheds. Weathering Rate Although decreased contributions from carbonate weathering have been observed with increased ex posure age in felsic terrains for proglacial systems ( White et al., 1999 ; Anderson et al., 2000 ; Jacobson and Blum, 2000 ; Jacobson et al., 2002 ; Wimpenny et al., 2010 ) , our results are the first we are aware of to document a similar shift in deglacial watersheds . The observed shift in watershed hydrogeochemistry over terrains that differ in exposure age by only ~2 3 ka is difficult to compare to timescales of change estimated in proglacial systems. Although the relative proportions of carbonate versus silicate we athering solutes change across all four studied watersheds, all of the watersheds still appear to be influenced by weathering of trace carbonates (Figure 4 1 C), thus the exposure age needed to generate a system dominated by silicate weathering is unknown. Jacobson et al. (2002 ) projected their data to estimate carbonate weathering predominance for tens of thousands of years in the Himalayas,

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50 but it is difficult to extrapolate that rate to the Greenland deglaciated watershed in part because western Greenland is tectonically more stable. We also observe a smaller offset between Sr isotope ratios in waters and bedload in the coastal watershed relative to the inland watershed. Blum and Erel (1997 ) found that Sr isotope ratios in moraine sediments began to weather congruently within ~20 ka following exposure, where th e offset in water bedload 87 Sr / 86 Sr decreases quickly in the first several ka from >0.040 to ~< 0.010, and then slowly reaches congruent ratios over the following thousands of years. While our field results may have limited comparability with laboratory results, it seems that the water bedload 87 Sr / 86 Sr is high in the inland watersheds relative to w atersheds of the same exposure age measured by Blum and Erel (1997 ) , but that offset at the coast is consistent with water sheds of the same exposure age in their study. We attribute the rapid decrease in the offset between water bedload 87 Sr / 86 Sr to the shift from negative to positive water balance between inland and coastal watersheds. Overall, though, our data suggest that changes in 87 Sr / 86 Sr in western Greenland may occur at a similar rate compared with Sr isotope results from Blum and Erel ( 1997 ) , but perhaps equilibrate more slowly nearer the GIS due to decreased precipitation. .

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51 CHAPTER 6 CONCLUSIONS This study provides the first assessment of weathering of minerals in deglaciated watersheds in western Greenland, which were exposed as the ice sheet retreated during the Holocene . Water chemical compositions were measured across a transect of four watersheds extending from near the coast to inland near the ice sheet. The two coastal watersheds (Sisimiut and Nerumaq) are located in mor aine sequences that were exposed ~10 ka in a region with a positive water balance (150 mm/yr). In contrast the two inland watersheds (Qorlortoq and Lake Helen) are located in a region with exposure ages of ~7.5 8 ky and a negative water balance ( 150 mm/yr ). The coastal watersheds have higher Na + /Cl , SO 4 2 /Cl , Si/Ca 2+ and modelled quartz/amorphous SiO 2 saturation states and lower Ca/Sr, 87 Sr / 86 Sr, and calcite mineral saturation than inland watersheds. Relative abundances of dissolved Si are greater and of HCO 3 /CO 3 2 are less in the coastal watersheds than the inland watersheds. These differences indicate a greater contribution to the dissolved ion concentrations from silicate and sulfate mineral weathering in coastal watersheds and a greater contributio n from carbonate weathering at inland watersheds. Because carbonate minerals weather more readily, this transition suggest s the coastal region has experienced more chemical weathering than inland sites, regardless of their relatively small differences in e xposure age . More extensive chemical weathering at the coast is also shown in comparisons of Sr isotopic compositions of bedload and water samples from one coastal and one inland watershed. Stream bedload Sr isotopic signatures for the two regions are simi lar relative to the range of values observed in these terrains, but all water sampled is more

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52 radiogenic than the bedload sediment. The difference between water and bedload 87 Sr / 86 Sr values is three times greater at the inland and coastal watershed. The offset in both watersheds reflects incongruent silicate weathering, but the smaller offset at the coastal site reflects more intense weathering there. W eathering in glacial watersheds is largely controlled by exposure age and precipitation. The ~2 3 ka di fference in exposure age along the transect correlates to variations in dissolved ions and isotopes that are similar in magnitude to variations documented in numerous alpine proglacial watersheds ; however, the gradient in weathering intensity between the d eglacial inland and coastal watersheds appears to be steeper than the gradient observed in alpine proglacial watersheds. The steeper gradient corresponds to the precipitation gradient from inland to the coast, which may enhance the control on weathering fr om exposure age. Although exposure age may modulate weathering reactions over thousands to tens of thousands of years, abrupt changes in precipitation over small areas have the potential to significantly impact the timescale of deglacial weathering. While highlights the need for more research in deglacial watersheds because the relative proportions of solute fluxes to the ocean from deglacial watersheds compared with proglacial systems will increase as the GIS retreats. Small variations in exposure age and climatic conditions considerably alter the chemical compositions of discharge from these watersheds and thus their flux of solutes to the oceans . Improving constraints on the evolution of weathering reactions in deglacial watersheds will increase our understanding of how these weathering environments contributed to changes in ocean

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53 chemistry and the global carbon budget in the past, and will help us predict how they will influence future c ycles. .

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54 APPENDIX A STABLE ISOTOPE S Figure A 1 . D versus compared to the global, Grønnedal, and Thule meteoric water lines (Craig, 1961; Leng & Anderson, 2003). Errors are smaller than data points.

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55 APPENDIX B SISIMIUT DATA Table B 1 . Sisimiut field data. ID Latitude Longitude Date Temp. Sp.Cond DO DO pH ORP °N °W ° C µS/cm % mg/l S1 M1 66.950850 53.543250 6/18/2013 10.2 45.7 100.2 11.2 7.23 123.5 S1 M2 66.943060 53.625030 6/20/2013 7.2 62 .0 100.5 12.1 7.25 146.4 S1 T1 1 66.934840 53.529220 6/17/2013 2.8 42.8 87.7 11.9 6.68 85.7 S1 T1 2 66.944100 53.470880 6/17/2013 8.7 68.4 90.4 10.5 7.02 134.9 S1 T2 1 66.950100 53.452620 6/18/2013 8.7 31.2 97.5 11.4 7.08 107.6 S1 T2 2 66.944540 53.470120 6/18/2013 9.1 33.5 95.8 11.0 7.15 103.3 S1 T3 1 66.951520 53.485600 6/18/2013 8.0 39.3 93.7 11.1 7.08 120.2 S1 T4 1 66.937030 53.534390 6/20/2013 5.9 36.2 93.8 11.7 6.95 118.7 S1 T4 2 66.939520 53.570860 6/20/2013 5.9 48.6 92.4 11.5 7.18 134.2 S1 T5 1 66.972270 53.486700 6/23/2013 8.1 56.6 95.7 11.3 7.31 179.5 S1 T5 2 66.964940 53.511750 6/23/2013 7.5 58.3 93.2 11.2 7.3 0 188.8 S1 T5 3 66.951970 53.562500 6/23/2013 11.0 53.1 100.6 11.1 7.13 118.7 S2 M1 66.969130 53.705780 6/19/2013 3.6 59.9 97.5 12.9 6.45 156.0 S3 M1 66.967630 53.678040 6/19/2013 7.2 38.9 93.7 11.4 6.87 102.7 S3 M2 66.964100 53.675770 6/19/2013 7.9 45.8 95.8 11.3 7.11 105.0 S3 M3 66.955540 53.697380 6/19/2013 10.1 48.0 92.3 10.4 7.24 106.4 S3 M4 66.951010 53.702350 6/20/2013 8.2 52.2 94.7 11.2 7.16 150.0 Site Average 66.952479 53.570720 7.7 48.3 95.0 11.4 7.07 128.3

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56 Table B 2 . Sisimiut stable isotope and major ion data. ID 18 O D 13 C Na K Mg Ca Cl SO 4 Alk . mM mM mM mM mM mM mM S1 M1 8.43 100.96 3.63 0.13 0.01 0.06 0.06 0.12 0.08 0.16 S1 M2 8.17 100.62 4.52 0.20 0.01 0.07 0.08 0.14 0.10 0.16 S1 T1 1 8.15 97.65 9.26 0.12 0.01 0.05 0.05 0.12 0.08 0.15 S1 T1 2 8.27 99.50 6.88 0.14 0.01 0.10 0.10 0.13 0.16 0.17 S1 T2 1 8.26 101.20 3.10 0.10 0.01 0.04 0.04 0.10 0.04 0.16 S1 T2 2 8.53 103.25 3.39 0.11 0.01 0.04 0.04 0.11 0.05 0.14 S1 T3 1 8.23 100.82 4.25 0.11 0.01 0.04 0.06 0.11 0.06 0.11 S1 T4 1 7.86 97.45 6.19 0.12 0.01 0.04 0.05 0.12 0.05 0.16 S1 T4 2 7.75 97.82 3.29 0.15 0.01 0.06 0.07 0.14 0.07 0.13 S1 T5 1 8.17 102.77 4.08 0.13 0.01 0.07 0.11 0.13 0.09 0.27 S1 T5 2 7.85 100.78 2.80 0.14 0.01 0.07 0.10 0.11 0.10 0.24 S1 T5 3 7.88 100.31 4.87 0.16 0.01 0.06 0.08 0.12 0.09 0.24 S2 M1 7.59 94.53 15.77 0.20 0.01 0.07 0.07 0.19 0.07 0.19 S3 M1 7.66 95.68 8.50 0.14 0.01 0.05 0.05 0.14 0.04 0.16 S3 M2 7.67 96.01 5.59 0.15 0.01 0.05 0.06 0.14 0.06 0.19 S3 M3 7.44 95.33 3.79 0.17 0.01 0.05 0.06 0.15 0.06 0.17 S3 M4 7.33 95.17 3.03 0.18 0.01 0.06 0.07 0.15 0.07 0.19 Site Average 7.96 98.81 5.47 0.14 0.01 0.06 0.07 0.13 0.07 0.18

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57 Table B 3 . Sisimiut Minor Element Data. ID Si Fe Mn Sr Nd Pb µM µM µM µM pM pM S1 M1 38.6 0.366 0.011 0.404 360.7 189.3 S1 M2 53.9 0.631 0.000 0.528 432.5 40.9 S1 T1 1 29.6 1.894 0.963 0.206 76.4 30.9 S1 T1 2 44.6 0.371 0.035 0.477 251.9 28.3 S1 T2 1 30.6 0.196 b.d.* 0.382 268.6 16.7 S1 T2 2 30.0 0.064 b.d.* 0.298 285.8 12.5 S1 T3 1 38.3 0.097 b.d.* 0.551 576.1 36.8 S1 T4 1 39.3 0.287 0.001 0.242 368.0 34.3 S1 T4 2 49.6 0.104 b.d.* 0.422 416.2 14.5 S1 T5 1 38.6 0.072 b.d.* 1.192 636.9 11.8 S1 T5 2 39.3 0.024 b.d.* 1.019 621.6 8.7 S1 T5 3 43.6 1.134 0.028 0.706 669.9 19.2 S2 M1 59.9 0.224 b.d.* 0.759 2613.7 53.4 S3 M1 26.0 1.191 0.026 0.432 636.2 43.9 S3 M2 29.6 0.782 0.004 0.580 893.5 18.5 S3 M3 26.3 0.683 0.003 0.576 983.9 42.9 S3 M4 27.0 0.570 0.004 0.644 979.2 251.4 Site Average 37.9 0.511 0.107 0.554 651.2 50.2 * Below Detection

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58 APPENDIX C NERUMAQ DATA Table C 1 . Nerumaq field data. ID Latitude Longitude Date Temp Sp. Cond DO DO pH ORP °N °W ° C µS/cm % mg/l N1 M1 67.011570 52.868850 6/30/2013 5.2 120.5 90.5 11.5 7.06 159.7 N1 M2 67.004900 52.912800 6/30/2013 6.8 123.3 92.6 11.3 7.22 193.6 N1 M3 67.005090 52.964570 7/2/2013 11.0 118.0 107.3 11.8 7.45 196.3 N1 M4 67.016070 53.030320 7/1/2013 10.6 100.4 91.1 10.1 7.20 156.4 N1 M5 67.011760 53.084670 7/1/2013 10.9 94.9 97.2 10.7 7.30 190.1 N1 T1 1 67.028750 52.759150 6/26/2013 10.1 70.7 90.4 10.2 7.36 146.3 N1 T1 2 67.012180 52.835470 6/27/2013 9.9 97.6 92.3 10.5 6.96 151.2 N1 T1 3 67.011600 52.863250 6/27/2013 10.5 130.2 91.9 10.3 7.12 173.3 N1 T2 1 67.027530 52.794280 6/26/2013 0.6 18.9 90.0 12.9 7.00 172.2 N1 T2 2 67.026170 52.798850 6/26/2013 16.5 46.8 98.5 9.6 7.91 162.2 N1 T2 3 67.018600 52.827210 6/27/2013 8.1 118.4 86.0 10.2 7.21 182.7 N1 T2 4 67.012700 52.860630 6/27/2013 11.5 119.8 93.8 10.2 7.69 168.1 N1 T3 1 67.014490 52.863220 6/30/2013 5.2 69.5 91.0 11.6 7.42 209.3 N1 T3 2 67.011960 52.867280 6/30/2013 4.8 81.6 93.9 12.1 7.28 148.3 N1 T4 1 67.027790 52.950460 7/2/2013 5.5 32.0 96.2 12.1 6.78 149.0 N1 T4 2 67.014790 53.091640 7/1/2013 11.2 54.2 94.7 10.4 7.35 180.9 N1 T5 1 67.015940 53.019150 7/1/2013 3.7 58.3 96.8 12.8 6.26 163.6 N1 T6 1 67.015240 52.941920 7/2/2013 13.9 67.9 85.5 8.8 6.88 147.2 N1 T6 2 67.007480 52.962850 7/2/2013 11.8 101.2 95.6 10.4 7.70 150.7 N1 T7 1 67.003530 52.914730 7/3/2013 7.5 105.2 105.0 12.6 6.96 229.6 N1 T8 1 67.003380 52.916040 7/3/2013 10.4 87.4 104.6 11.7 7.19 216.2 N1 T9 1 66.998410 52.947720 7/3/2013 4.9 108.0 99.4 12.7 6.74 230.9 Site Average 67.013633 52.912503 8.7 87.5 94.7 11.1 7.18 176.3

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59 Table C 2 . Nerumaq stable isotope and major ion data. ID 18 O D 13 C Na K Mg Ca Cl SO 4 Alk . mM mM mM mM mM mM mM N1 M1 8.99 112.16 8.77 0.16 0.02 0.16 0.26 0.12 0.32 0.34 N1 M2 8.99 111.82 7.33 0.16 0.02 0.17 0.28 0.12 0.32 0.33 N1 M3 8.94 111.26 7.34 0.16 0.02 0.15 0.25 0.12 0.31 0.57 N1 M4 9.04 111.49 6.97 0.15 0.02 0.13 0.20 0.11 0.26 0.08 N1 M5 9.29 110.70 5.20 0.16 0.02 0.13 0.18 0.11 0.24 0.26 N1 T1 1 7.61 103.98 5.62 0.10 0.02 0.09 0.16 0.10 0.09 0.36 N1 T1 2 9.26 111.79 9.36 0.17 0.02 0.13 0.19 0.13 0.23 0.24 N1 T1 3 9.31 112.50 8.51 0.16 0.02 0.19 0.28 0.12 0.40 0.18 N1 T2 1 9.46 109.45 9.91 0.04 0.01 0.02 0.04 0.06 0.01 0.16 N1 T2 2 9.37 112.67 7.11 0.08 0.01 0.06 0.11 0.09 0.05 0.35 N1 T2 3 9.15 111.03 10.87 0.17 0.02 0.17 0.27 0.13 0.18 0.60 N1 T2 4 9.05 110.93 7.77 0.18 0.02 0.17 0.28 0.14 0.18 0.62 N1 T3 1 8.37 108.74 4.54 0.10 0.01 0.08 0.16 0.09 0.13 0.34 N1 T3 2 8.54 108.53 6.83 0.11 0.02 0.09 0.20 0.09 0.16 0.36 N1 T4 1 7.87 105.67 5.01 0.08 0.01 0.04 0.05 0.09 0.05 0.16 N1 T4 2 8.02 105.34 2.29 0.13 0.01 0.07 0.09 0.10 0.08 0.25 N1 T5 1 9.37 112.56 14.61 0.12 0.01 0.08 0.08 0.10 0.15 0.10 N1 T6 1 8.77 110.32 9.12 0.11 0.01 0.11 0.12 0.09 0.14 0.27 N1 T6 2 8.85 111.21 4.05 0.15 0.02 0.17 0.18 0.10 0.24 0.40 N1 T7 1 9.40 113.76 4.83 0.15 0.02 0.15 0.20 0.10 0.32 0.32 N1 T8 1 9.10 112.85 1.95 0.14 0.02 0.12 0.16 0.10 0.24 0.24 N1 T9 1 8.58 108.04 12.39 0.14 0.03 0.14 0.26 0.11 0.23 0.45 Site Average 8.88 110.31 7.29 0.13 0.02 0.12 0.18 0.10 0.20 0.32

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60 Table C 3 . Nerumaq Minor Element Data. ID Si Fe Mn Sr Nd Pb µM µM µM µM pM pM N1 M1 26.0 1.513 0.163 1.157 783.9 78.5 N1 M2 85.9 1.338 0.136 1.460 874.4 3.0 N1 M3 43.3 1.573 0.096 1.356 613.8 b.d.* N1 M4 63.9 0.833 0.036 0.955 576.2 36.4 N1 M5 107.2 0.943 0.028 0.785 583.2 b.d.* N1 T1 1 33.3 0.747 0.227 0.701 189.3 b.d.* N1 T1 2 84.5 1.317 0.105 1.063 936.3 0.3 N1 T1 3 70.6 2.278 0.222 1.482 833.6 b.d.* N1 T2 1 14.0 0.142 0.010 b.d.* 816.3 15.9 N1 T2 2 10.7 1.128 0.017 0.165 850.6 18.0 N1 T2 3 93.9 0.774 0.033 1.143 754.5 b.d.* N1 T2 4 42.6 2.016 0.004 1.045 705.1 0.1 N1 T3 1 46.6 0.040 b.d.* 0.845 607.8 b.d.* N1 T3 2 46.9 0.637 0.019 0.921 698.6 b.d.* N1 T4 1 12.0 b.d.* 0.003 0.170 149.0 12.4 N1 T4 2 38.6 0.206 b.d.* 0.512 350.2 45.3 N1 T5 1 51.3 0.030 0.011 0.181 570.1 b.d.* N1 T6 1 43.6 1.481 0.092 0.510 652.1 b.d.* N1 T6 2 98.5 0.025 b.d.* 0.754 679.8 b.d.* N1 T7 1 77.9 0.007 b.d.* 0.765 708.3 30.1 N1 T8 1 79.9 b.d.* b.d.* 0.556 643.9 b.d.* N1 T9 1 39.6 0.027 b.d.* 0.764 3234.0 17.2 Site Average 55.0 0.773 0.075 0.823 764.1 23.4 * Below Detection

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61 Table C 4 . Nerumaq radiogenic isotope data. ID Bedload 87 Sr/ 86 Sr Error Water 87 Sr/ 86 Sr Error N1 M1 0.70637 0.000022 0.71057 0.000014 N1 M2 0.70667 0.000034 0.71074 0.000022 N1 M3 0.70885 0.000026 0.71097 0.000038 N1 M4 0.70704 0.000038 0.71163 0.000017 N1 M5 0.70632 0.000022 0.71179 0.000016 N1 T1 1 0.70766 0.000026 0.71170 0.000022 N1 T1 2 0.70766 0.000026 0.71077 0.000020 N1 T1 3 0.70734 0.000020 0.71053 0.000017 N1 T2 1 0.71093 0.000044 0.71905 0.000022 N1 T2 2 0.70842 0.000030 0.71800 0.000020 N1 T2 3 0.70687 0.000036 0.71293 0.000018 N1 T2 4 0.70698 0.000030 0.71343 0.000014 N1 T3 1 0.70862 0.000022 0.71014 0.000017 N1 T3 2 0.70862 0.000022 0.71058 0.000020 N1 T4 1 0.70716 0.000032 0.71207 0.000016 N1 T4 2 0.70693 0.000026 0.70808 0.000017 N1 T5 1 0.70685 0.000028 0.71444 0.000018 N1 T6 1 0.70758 0.000028 0.71372 0.000023 N1 T6 2 0.70669 0.000020 0.71512 0.000016 N1 T7 1 0.70694 0.000028 0.71356 0.000017 N1 T8 1 0.70744 0.000020 0.71401 0.000020 N1 T9 1 0.70788 0.000026 0.71663 0.000024

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62 APPENDIX D QORLORTOQ DATA Table D 1 . Qorlortoq field data. ID Latitude Longitude Date Temp Sp. Cond DO DO pH ORP °N °W ° C µS/cm % mg/l Q1 T1 1 67.030160 51.288010 7/19/2013 7.4 191.4 82.3 9.9 6.68 186.4 Q1 T1 2 67.033000 51.284660 7/19/2013 10.7 194.3 89.2 9.9 6.84 129.1 Q1 T1 3 67.040300 51.310000 7/19/2013 18.2 166.1 113.8 10.7 9.22 120.2 Q1 T1 4 67.039570 51.348210 7/20/2013 19.7 215 .0 106.2 9.7 9.57 174.3 Q1 T2 1 67.052500 51.335030 7/20/2013 14.8 150.2 94.9 9.6 8.2 0 157.1 Q1 T2 2 67.044180 51.347590 7/20/2013 16.6 158.4 88.6 8.5 7.97 175.2 Q1 T3 1 67.054760 51.381030 7/20/2013 16.1 105 .0 103.9 10.3 8.32 147.6 Q1 T3 2 67.063030 51.334030 7/20/2013 15.8 119.4 99.8 9.9 8.21 165 .0 Q1 T3 3 67.053850 51.338580 7/20/2013 8.9 147.4 79.4 9.2 7.41 179.5 Q1 M1 67.035150 51.360230 7/22/2013 21.1 183.2 121.3 10.8 8.98 137.6 Q1 M2 67.028660 51.365690 7/22/2013 19.1 212.9 116.3 10.7 9.17 123.2 Q1 M3 67.018220 51.431640 7/21/2013 15.1 243.9 94.5 9.5 8.47 108.9 Q1 M4 67.008900 51.466780 7/21/2013 16.8 373.6 95.3 9.3 8.79 163.6 Q2 T1 1 67.010700 51.369220 7/23/2013 15.7 451.8 92.2 9.1 8.45 200.9 Q2 T1 2 67.011050 51.376340 7/23/2013 4.8 462.1 89 .0 11.4 7.82 222.6 Q2 T2 1 66.996430 51.381510 7/23/2013 19.1 200.9 86.4 8.0 8.27 192.8 Q2 T2 2 67.006520 51.379660 7/23/2013 21.1 207.4 107.6 9.6 8.88 172.3 Q2 M1 67.015810 51.394480 7/21/2013 11.6 301.9 92.3 11.0 7.6 0 139.2 Q2 M2 67.005530 51.459640 7/21/2013 18.2 1632 .0 107.6 10.1 7.71 159.6 Site Average 67.028859 51.365912 15.3 300.9 97.9 9.8 8.24 160.8

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63 Table D 2 . Qorlortoq stable isotope and major ion data. ID 18 O D 13 C Na K Mg Ca Cl SO 4 Alk . mM mM mM mM mM mM mM Q1 T1 1 8.53 117.17 15.91 0.23 0.08 0.27 0.49 0.24 0.43 0.58 Q1 T1 2 8.10 114.29 14.28 0.28 0.09 0.28 0.45 0.28 0.41 0.61 Q1 T1 3 3.18 92.82 1.81 0.30 0.11 0.27 0.34 0.29 0.14 0.96 Q1 T1 4 2.99 92.42 5.28 0.46 0.12 0.33 0.46 0.42 0.15 1.34 Q1 T2 1 2.98 91.42 0.21 0.22 0.09 0.25 0.32 0.20 0.14 0.97 Q1 T2 2 3.04 92.12 4.48 0.24 0.09 0.25 0.35 0.22 0.14 0.99 Q1 T3 1 3.38 92.75 0.58 0.18 0.06 0.13 0.25 0.17 0.04 0.76 Q1 T3 2 3.82 95.47 3.88 0.20 0.07 0.16 0.29 0.20 0.06 0.81 Q1 T3 3 3.89 96.21 9.42 0.23 0.08 0.20 0.38 0.21 0.09 1.06 Q1 M1 3.05 91.93 2.34 0.41 0.11 0.28 0.37 0.38 0.15 1.03 Q1 M2 3.34 92.62 3.47 0.59 0.10 0.32 0.38 0.59 0.16 1.07 Q1 M3 3.25 93.00 6.20 0.63 0.11 0.37 0.44 0.65 0.19 1.18 Q1 M4 2.84 91.33 6.60 1.37 0.13 0.51 0.51 1.66 0.26 1.25 Q2 T1 1 2.28 88.15 2.17 0.89 0.31 0.62 1.14 0.86 0.46 2.67 Q2 T1 2 2.44 89.14 6.96 0.87 0.29 0.62 1.20 0.87 0.56 2.60 Q2 T2 1 3.46 93.72 2.95 0.31 0.12 0.28 0.46 0.25 0.38 0.81 Q2 T2 2 2.67 90.36 3.42 0.32 0.11 0.29 0.48 0.27 0.38 0.84 Q2 M1 3.52 93.98 8.98 0.44 0.15 0.42 0.76 0.42 0.60 1.20 Q2 M2 2.63 89.47 10.88 7.49 0.33 1.97 1.76 7.01 2.10 1.52 Site Average 3.65 94.65 5.78 0.82 0.13 0.41 0.57 0.80 0.36 1.17

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64 Table D 3 . Qorlortoq Minor Element Data. ID Si Fe Mn Sr Nd Pb µM µM µM µM pM pM Q1 T1 1 61.6 1.093 0.105 0.649 11293.8 168.2 Q1 T1 2 76.6 6.525 0.209 0.643 5601.0 72.9 Q1 T1 3 4.7 0.282 0.019 0.489 271.3 116.6 Q1 T1 4 11.2 0.254 0.061 0.630 470.2 40.3 Q1 T2 1 4.3 0.132 0.035 0.458 447.5 35.2 Q1 T2 2 8.7 0.321 0.046 0.614 363.6 53.3 Q1 T3 1 5.0 0.141 0.000 0.528 126.4 84.6 Q1 T3 2 8.0 0.263 0.012 0.635 206.0 49.9 Q1 T3 3 25.6 0.176 b.d.* 0.796 860.8 110.6 Q1 M1 7.0 0.207 0.023 0.589 195.4 98.4 Q1 M2 4.7 0.358 0.049 0.663 253.8 73.7 Q1 M3 9.7 0.472 0.018 0.782 293.8 51.9 Q1 M4 9.3 0.294 0.171 1.077 266.7 57.5 Q2 T1 1 7.3 0.128 0.002 1.586 496.2 67.0 Q2 T1 2 35.4 0.199 b.d.* 1.603 1745.1 199.5 Q2 T2 1 8.0 0.182 0.050 0.558 670.7 53.9 Q2 T2 2 6.7 0.555 0.041 0.578 648.9 44.1 Q2 M1 36.9 0.495 0.060 0.955 1425.0 52.1 Q2 M2 15.3 1.458 0.418 3.274 575.1 38.1 Site Average 18.2 0.712 0.078 0.900 1379.5 77.3 * Below Detection

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65 Table D 4 . Qorlortoq Radiogenic Isotope Data. ID Bedload 87 Sr/ 86 Sr Error Water 87 Sr/ 86 Sr Error Q1 T1 3 0.71389 0.000018 0.73775 0.000015 Q1 M1 0.71220 0.000022 0.73046 0.000021 Q1 M2 0.71720 0.000024 0.72981 0.000044 Q1 M3 0.71720 0.000024 0.72971 0.000016 Q1 M4 0.71529 0.000022 0.72712 0.000014 Q2 M1 0.71183 0.000022 0.73837 0.000015

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66 APPENDIX E LAKE HELEN DATA Table E 1 . Lake Helen Field Data. ID Latitude Longitud e Date Tem p Sp. Cond DO DO pH ORP °N °W ° C µS/cm % mg/l DG 8 1 1 67.023350 50.825520 6/9/2013 14.4 55.4 96.4 9.3 7.33 134.1 DG 8 2 1 67.016920 50.856200 6/9/2013 3.8 75.0 81.1 10.7 6.86 121.9 DG 8 3 1 67.008150 50.876080 6/9/2013 4.6 110.7 90.0 11.6 7.16 115.6 DG 8 4 1 66.989580 50.931080 6/11/2013 6.1 107.4 75.1 9.3 6.96 178.2 DG 8 5 1 66.968610 50.954750 6/10/2013 8.4 144.8 99.0 11.6 7.88 174.1 DG 8 1 2 67.923410 50.825750 7/12/2013 15 102.3 94.2 9.5 8.09 173.7 DG 8 2 2 67.015600 50.860850 7/12/2013 3.5 124.7 86.9 11.5 7.39 154.7 DG 8 3 2 67.008160 50.876090 7/12/2013 4.4 133.3 89.1 11.5 7.39 151.9 DG 8 4 2 67.989650 50.931270 7/12/2013 7.8 198.2 74.5 8.8 7.26 201.2 DG 8 5 2 66.968660 50.954680 7/12/2013 8.8 236.5 92.9 10.8 8.09 195.6 DG 8 1 3 67.023410 50.825750 7/28/2013 13.6 115.2 102.0 10.6 8.06 127.1 DG 8 2 3 67.015600 50.860850 7/28/2013 3.1 180.0 74.9 10.1 7.02 92.3 DG 8 3 3 67.008160 50.876090 7/28/2013 5.0 162.6 91.8 11.7 7.34 79.8 DG 8 4 3 66.989430 50.931220 7/28/2013 8.2 257.6 89.5 10.6 6.97 147.2 DG 8 5 3 66.968640 50.954630 7/28/2013 10.0 290.0 102.4 11.6 7.90 227.8 Site Average 67.127822 50.889387 7.8 152.9 89.3 10.6 7.45 151.7 June 9th Average 67.001322 50.888726 7.5 98.7 88.3 10.5 7.24 144.8 July 12th Average 67.381096 50.889728 7.9 159.0 87.5 10.4 7.64 175.4 July 28th Average 67.001048 50.889708 8.0 201.1 92.1 10.9 7.46 134.8

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67 Table E 2 . Lake Helen Stable Isotope and Major Ion Data. ID 18 O D 13 C Na K Mg Ca Cl SO 4 Alk . mM mM mM mM mM mM mM DG 8 1 1 4.82 102.35 0.03 0.08 0.05 0.11 0.11 0.07 0.03 0.50 DG 8 2 1 6.10 106.38 13.55 0.11 0.06 0.16 0.15 0.10 0.04 0.66 DG 8 3 1 5.68 105.26 11.09 0.22 0.10 0.22 0.19 0.20 0.05 0.86 DG 8 4 1 4.17 98.41 7.77 0.20 0.08 0.20 0.20 0.17 0.04 0.82 DG 8 5 1 4.51 100.47 6.11 0.29 0.11 0.27 0.28 0.26 0.07 1.10 DG 8 1 2 3.89 96.58 2.83 0.15 0.08 0.22 0.20 0.13 0.05 0.75 DG 8 2 2 4.91 102.38 10.82 0.18 0.08 0.26 0.25 0.16 0.08 0.85 DG 8 3 2 4.98 102.16 10.39 0.20 0.09 0.27 0.27 0.18 0.10 0.87 DG 8 4 2 4.42 100.83 12.17 0.33 0.11 0.42 0.41 0.34 0.14 1.28 DG 8 5 2 4.96 102.66 10.61 0.44 0.15 0.46 0.48 0.46 0.18 1.41 DG 8 1 3 3.78 96.82 4.90 0.18 0.08 0.26 0.24 0.16 0.04 0.93 DG 8 2 3 5.78 106.38 12.75 0.33 0.12 0.36 0.34 0.37 0.13 1.08 DG 8 3 3 5.49 105.11 11.18 0.27 0.10 0.34 0.33 0.28 0.12 1.01 DG 8 4 3 6.49 110.70 12.88 0.44 0.12 0.54 0.55 0.56 0.23 1.55 DG 8 5 3 5.66 107.42 11.68 0.51 0.17 0.59 0.62 0.60 0.24 1.84 Site Average 5.04 102.93 9.25 0.26 0.10 0.31 0.31 0.27 0.10 1.03 June 9th Average 5.06 102.57 7.70 0.18 0.08 0.19 0.18 0.16 0.04 0.79 July 12th Average 4.63 100.92 9.36 0.26 0.10 0.32 0.32 0.26 0.11 1.03 July 28th Average 5.44 105.29 10.68 0.34 0.12 0.42 0.42 0.39 0.15 1.28

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68 Table E 3 . Lake Helen Minor Element Data . ID Si Fe Mn Sr Nd Pb µM mM µM µM pM pM DG 8 1 1 4.3 3.914 0.115 0.125 941.3 122.0 DG 8 2 1 19.1 0.702 0.057 0.181 1698.6 115.6 DG 8 3 1 24.0 1.656 0.185 0.257 2879.5 26.0 DG 8 4 1 9.7 4.076 0.172 0.298 1781.6 117.7 DG 8 5 1 17.6 1.071 0.034 0.449 2307.3 225.9 DG 8 1 2 4.3 4.296 0.076 0.241 1719.6 52.6 DG 8 2 2 40.1 1.238 0.136 0.321 2335.2 98.3 DG 8 3 2 38.6 1.496 0.152 0.381 3854.5 327.9 DG 8 4 2 27.3 4.068 0.150 0.610 2325.4 37.4 DG 8 5 2 66.6 0.305 0.016 0.812 1529.0 53.5 DG 8 1 3 10.7 6.845 0.483 0.300 1642.1 145.8 DG 8 2 3 57.3 6.168 1.184 0.458 3628.0 41.5 DG 8 3 3 47.6 1.693 0.188 0.472 4279.7 37.0 DG 8 4 3 28.6 7.326 0.560 0.831 3575.6 78.1 DG 8 5 3 16.6 0.363 0.018 1.065 1544.8 119.0 Site Average 27.5 3.014 0.235 0.454 2402.8 106.5 June 9th Average 14.9 2.284 0.113 0.262 1921.7 121.4 July 12th Average 35.4 2.281 0.106 0.473 2352.7 113.9 July 28th Average 32.2 4.479 0.487 0.625 2934.0 84.3

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77 BIOGRAPHICAL SKETCH Cecilia Scribner grew up in Waterbury Center, VT. She completed her Bachelor of Science degree at the University of Rochester in 2012. She graduated from the Department of Earth and Environmental Sciences department cum laude with high honors in research for her work on South African paleomagnetics. She began her Master of Science degree in geological scie nces at the University of Florida during the summer of 2012 as part of a field sampling team in western Greenland. Her work focused on hydrogeochemical differences between deglacial watersheds of varying ages, undertaken as part of a pilot project which jo hydrology and isotope geochemistry. Cecilia is a lover of the outdoors and of music.