A Thesis Entitled Origins of Basal Sediment Within Kettle Lakes In

A Thesis

entitled

Origins of Basal Sediment within Kettle Lakes in Southern Michigan and Northern

Indiana

Mitchell R. Dziekan

Submitted to the Graduate Faculty as partial fulfillment of the requirements for the

Master of Science Degree in

Geology

______Timothy G. Fisher, Ph.D., Committee Chair

______James M. Martin-Hayden, Ph.D., Committee Member

______Henry M. Loope, Ph.D., Committee Member

______B. Brandon Curry, Ph.D., Committee Member

______Amanda Bryant-Friedrich, PhD, Dean College of Graduate Studies

The University of Toledo

October 2017

This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author.

An Abstract of

Origins of Basal Sediment in Kettle Lakes in Southern Michigan and Northern Indiana

Mitchell R. Dziekan

Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science Degree in Geology

The University of Toledo

October 2017

Finding datable material to constrain ages of deglaciation is a key challenge faced by many Quaternary geologists. Often kettle lakes contain datable material in the form of wood and other terrestrial macrofossils within their basal sediment. These sediment units are frequently sandy layers interpreted as being deposited during downwasting as ice blocks melt within a growing kettle basin. This melting process takes time, resulting in a lag between deglaciation and the radiocarbon ages obtained from these units. Though extensively used in dating deglacial events associated with the retreat of the Laurentide

Ice Sheet, little effort has been made to study this lag time and quantify its duration. This study’s main objective was to characterize the depositional environment of these “basal trash layers” and determine the extent of melt-out time lags in the region previously covered by the Saginaw Lobe of the Laurentide Ice Sheet.

Six lakes along the Shipshewana and Sturgis moraines in northern Indiana and southern Michigan were cored and two separate lithofacies were consistently recovered: a lower pebbly sand with variable organic content, and an upper lacustrine mud. The lower pebbly sand does not exhibit the depositional characteristics frequently described for i

basal trash layers. Instead, the stratigraphic, geochemical, and physical characteristics of this lower facies suggest deposition by glaciofluvial, fluvial, and/or littoral processes.

Radiocarbon and optically stimulated luminescence chronology from these cores largely does not constrain the extent of melt-out time lags within these basins, aside from two lakes, where melt-out time lags of 5 ka and 7 ka are documented based on differences between basal OSL and radiocarbon ages. These OSL ages provided potential minimum ages for the Sturgis and Shipshewana moraines of 20.4 ± 1.4 ka and 23.6 ± 1.1 ka respectively, and may also provide evidence of an earlier retreat of the Saginaw Lobe than previously inferred.

Furthermore, basal radiocarbon sampling from these lakes continuously provided ages of ~16.0 cal ka BP. This consistency may mark a regional climate signal, indicative of warming in this region of North America, potentially related to Heinrich Event 1 and the climate conditions of the mystery interval between 17.5─14.9 ka.

Acknowledgements

This work would not have been possible if it were not for the support of a number of individuals along the way. Dr. Timothy Fisher, my primary advisor, was instrumental in helping develop my skills as a writer, a presenter and as a scientist. My committee members Dr. James Martin-Hayden, Dr. Henry Loope, and Dr. B. Brandon Curry all provided me with insight and guidance throughout the research process.

Thanks are also extended to Dr. Kenneth Lepper and Dr. Francine McCarthy for their collaboration in this project through OSL dating and pollen analysis, respectively. I thank my fellow students Jonathan Luczak, John Dilworth, Lucas Groat and Amy Towell for their help in the field and in the lab. Roy Schneider and Daniel Brainard at the UTMC for their assistance in CT scanning of sediment cores. Kristina Brady and the rest of the staff at LacCore for the amazing experience in Minneapolis. The USDA lab at UT for their help with CN analysis. Lastly I would also like to thank the multiple land owners who graciously took the time to chat with me and invited me onto their property (in some cases with absolutely no guidance and one herd of very friendly cows).

Funding for this research was provided by the USGS Mapping Coalition, the

Indiana Geologic Survey, a GSA graduate research grant, the LacCore and Continental

Scientific Drilling Coordination Office (CSDCO) Visiting Graduate Student Travel Grant

Program, and the University of Toledo’s Department of Environmental Sciences.

iii

Table of Contents

Abstract ...... i

Acknowledgements ...... iii

Table of Contents ...... iv

List of Tables ...... viii

List of Figures ...... ix

1 Introduction ...... 1

1.1 Introduction ...... 1

1.2 The Laurentide Ice Sheet ...... 2

1.3 The Saginaw Lobe ...... 3

1.4 Radiocarbon Dating and the Saginaw Lobe ...... 10

1.5 Melt-out Time Lags ...... 12

1.6 The Sturgis Moraine ...... 14

1.7 Deposition of Basal Trash Layers ...... 15

1.8 Depositional Systems in Post-glacial Landscapes ...... 18

1.9 Objectives and Hypothesis ...... 20

2 Methodology ...... 21

2.1 Introduction ...... 21

2.2 Lake Selection and Coring ...... 22

2.3 X-Ray Computed Tomography...... 23

2.4 The Limnological Research Center (LRC), Minneapolis, MN ...... 23

2.5 Grain Size Analysis...... 24

2.6 Loss-on-ignition ...... 25

2.7 Carbon/Nitrogen Ratios ...... 25

2.8 Radiocarbon Dating ...... 26

2.9 Pollen Analysis ...... 26

2.10 Optically Stimulated Luminescence Dating ...... 27

3 Results ...... 29

3.1 Introduction ...... 29

3.2 Lake Stratigraphy ...... 29

3.2.1 Thompson Lake ...... 32

3.2.2 Fish Lake ...... 36

3.2.3 Bullhead Lake ...... 38

3.2.4 Hunter Lake ...... 41

3.2.5 Stone Lake ...... 41

3.2.6 Meteer Lake ...... 45

3.3 Facies Descriptions ...... 46

3.4 Chronology ...... 50

3.4.1 Radiocarbon Dating ...... 50

3.4.2 Optically Stimulated Luminescence Dating ...... 51

3.4.3 Pollen ...... 52

4 Interpretations ...... 54

4.1 Introduction ...... 54 v

4.2 Depositional Environments ...... 54

4.2.1 Facies A: Basal Sand ...... 55

4.2.2 Facies B: Lacustrine Mud with Carbonate...... 56

4.2.3 Facies C: Lacustrine Carbonaceous Mud ...... 56

4.2.4 Facies D: Brecciated Sediment ...... 57

4.2.5 Facies E: Peat ...... 58

4.3 Core Chronology ...... 58

4.3.1 Meteer Lake ...... 58

4.3.2 Bullhead Lake ...... 59

4.3.3 Hunter Lake ...... 59

4.3.4 Fish Lake ...... 59

4.3.5 Stone Lake ...... 60

3.4.1 Thompson Lake ...... 61

5. Discussion ...... 62

5.1 Introduction ...... 62

5.2 Deposition of Basal Trash Layers ...... 62

5.3 Melt-out Time Lags and Regional Climate Signals ...... 64

6 Summary and Conclusions ...... 69

6.1 Summary ...... 69

6.2 Conclusions ...... 70

6.3 Implications...... 71

6.4 Future Work ...... 71

References ...... 73 vi

A Core Data Summary ...... 84

B Loss-on-ignition ...... 87

C Magnetic Susceptibility ...... 94

D Particle Size Analysis ...... 116

E Carbon/Nitrogen ...... 119

F Supplemental Data for OSL Dating ...... 124

G Supplemental Data for Pollen Analysis ...... 127

vii

List of Tables

3.1 Radiocarbon age data ...... 51

3.2 OSL ages and related data ...... 52

3.3 Pollen age estimates ...... 53

viii

List of Figures

1-1 Lobes of the Laurentide Ice Sheet ...... 4

1-2 Advances and readvances of the Wisconsin glaciation ...... 5

1-3 Reconstructed ice marginal positions ...... 6

1-4 Ice flow direction and major moraines of the Saginaw Lobe ...... 8

1-5 Drainage of pro-glacial Lake Maumee ...... 9

1-6 Interpreted flow paths of Kankakee Torrent ...... 11

1-7 Transition from glacial to lacustrine landscapes ...... 13

1-8 Stratigraphy of the Sturgis and Shipshewana moraines ...... 16

3-1 Lakes selected for coring ...... 30

3-2 Lakes and coring positions...... 31

3-3 Supporting legend for figures of basal stratigraphy ...... 33

3-4 Stratigraphy and chronology of Thompson Lake ...... 34

3-5 Particle size distribution of Thompson Lake’s Unit a ...... 35

3-6 Stratigraphy and chronology of Fish Lake...... 37

3-7 Particle size distribution of Fish Lake’s Unit a ...... 38

3-8 Stratigraphy and chronology of Bullhead Lake ...... 39

3-9 Particle size distribution of Bullhead Lake’s Unit a ...... 40

3-10 Stratigraphy and chronology of Hunter Lake ...... 42

3-11 Particle size distribution of Hunter’s Lake Unit a ...... 43

3-12 Stratigraphy and chronology of Stone Lake ...... 44

3-13 Particle size distribution of Stone Lake’s Unit a ...... 45

3-14 Charophyte stems from Stone Lake ...... 46

3-15 Stratigraphy and chronology of Meteer Lake ...... 47

3-16 Depths, lithofacies, and chronology of cored lakes ...... 48

5-1 Radiocarbon and OSL ages with GRIP ...... 66

6-1 Published radiocarbon ages in the Midwest United States ...... 72

Chapter 1

Introduction

1.1 Introduction

Accurately reconstructing the retreat of past ice sheets is a crucial component in understanding the geomorphology of a region, and how changes in paleoclimate influenced deglaciation. In areas such as the Great Lakes region of North America, which was extensively glaciated in the last 30,000 years, detailed reconstructions of deglaciation are essential to understanding climate change between the last glacial maximum (LGM) and the start of the Holocene epoch (~11,500 years ago). In addition, these reconstructions help shed light on the relationship between glacial ice and geomorphic features on the landscape today.

Though extensively studied, the retreat of the Laurentide Ice Sheet (the last ice sheet to cover the Great Lakes region) has little age control in a number of formerly glaciated regions. This lack of chronology frequently arises from sparse organics suitable for radiocarbon dating. In particular, the age of retreat of the Saginaw Lobe, located in

Michigan to northern Indiana, is very poorly constrained. Only a few radiocarbon ages in combination with geomorphic interpretations account for the nearly 6,000 years of the lobe’s retreat back into the Saginaw Bay from an undetermined maximum (Fullerton, 1

1980; Dyke, 2004). Though many other radiocarbon ages exist from this region, they often suffer from methods such as bulk-sampling radiocarbon dating and early methods of bone collagen processing now known to produce both under- and overestimated ages

(Grimm et al., 2009; Stafford et al., 1987). These developments, coupled with the scarcity of datable organic material in post-glacial sediment, has forced scientists to pursue new sources for radiocarbon dating, such as the basal sediment of inland lakes.

Many of the radiocarbon ages associated with deglaciation in the Great Lakes region come from the basal sediment of lakes and bogs. In the region formally glaciated by the Saginaw Lobe, these ages are frequently younger than the reconstructions predict.

Often this time discrepancy is accounted for by an assumed temporal gap between retreat of an ice sheet and the deposition of sediment within previously ice-filled lake basins.

This length of time is referred to as a melt-out time lag. Despite the wide application of melt-out time lags in deglacial studies, little research has been conducted to better constrain these time-lags and to understand their origin and variation. Thus, constraining the duration of these melt-out time lags and the depositional environments of the basal sedimentary units within inland lakes is critical to our acceptance of current deglacial reconstructions and could provide further information regarding the response of glaciers to changing climate in this particular region.

1.2 Laurentide Ice Sheet

The Laurentide Ice Sheet (LIS) (Figure 1.1) last entered the Great Lakes region during the Late Wisconsinan glaciation and reached and fluctuated at its last glacial maximum extent around 23-19 ka extending its sublobes into Wisconsin, Ohio, Indiana, 2

and Illinois (Larson and Schaetzl, 2001). After reaching its maximum extent, the ice sheet began its retreat characterized by multiple readvances before receding back into the

Hudson Bay (Fullerton, 1980; Mickelson et al., 1983; Dyke, 2004).

Four readvances during the recession of the LIS in the Great Lakes region have been documented and constrained through radiocarbon dating of key events around 16.8 cal ka BP, 13.6 cal ka BP, 11.7 cal ka BP, and 10.0 cal ka BP (Figure 1.2) (Lowell et al.,

1999). These events are referred to as the Port Bruce Stadial, Port Huron Stadial, Post-

Two Creeks Readvance, and the Lake Gribben Readvance, respectively. The latter readvances of the lobes in the Great Lakes region are well documented through many radiocarbon dates (Post Two Creeks and Lake Gribben), but earlier readvances are not, resulting in variable interpretations of their extent and timing. In well documented cases, readvances buried forests, providing ample material for radiocarbon dating.

1.3 The Saginaw Lobe

The Saginaw Lobe (SL) (Figure 1.1) is one of the more under-studied lobes of the

Laurentide Ice Sheet. Spanning from the Saginaw Bay of Michigan to an unknown position in northern Indiana, its chronology of advance and retreat are poorly constrained, and how it interacted with the adjacent Michigan and Huron-Erie lobes is not well documented in the literature. It is thought that at its maximum extent the lobe was overtaken by its adjacent lobes, leading to weakening and stagnation, followed by a more rapid retreat (Larson and Schaetzel, 2001). Reconstructed ice marginal positions of the

SL (Figure 1.3) interpret the lobe to have retreated back to the edge of the Saginaw Bay

Figure 1.1. Lobes of the Laurentide Ice Sheet, the Last Glacial Maximum during the

Late Wisconsin glaciation (modified from Kehew, 2012).

Figure 1.2. Advances and readvance of the Late Wisconsinan glaciation (modified from Larson and Schaetzl, 2001; Howard, 2010). Terminology used for the Erie and

Huron-Erie lobes. A) Ice marginal positions of the lobes in the Great Lakes region,

B) Timing of stadial and interstadial periods of the Laurentide Ice Sheet. 5

Figure 1.3. Reconstructed ice marginal positions from a radiocarbon database assembled by Dyke (2004). Key dates (yellow) are radiocarbon dates linked to specific geomorphic events and are most influential in reconstructing deglaciation.

Additional radiocarbon ages collected in the region which post-date these reconstructed ice margins are also shown (Horton, 2015; Glover et al., 2011). 6

by ~16.3 cal ka BP after a series of readvances (Fullerton, 1980; Dyke, 2004).This chronology is based primarily on correlations between moraines of adjacent lobes and two geomorphic events: the Kankakee Torrent and the draining of pro-glacial Lake

Maumee.

Only the Port Huron Moraine of the Saginaw Lobe (SLPHM) is formally assigned an age through association with the Port Huron Readvance. Although never directly dated, the SLPHM is assigned an age of ~15.5 ka from its geomorphic connection with the Port Huron Moraine of the Michigan Lobe (MLPHM) (Figure 1.4) whose inner moraine was assigned an age of 15.4 ± 0.6 cal ka BP (TX-6151) (Blewett et al., 1993).

The SLPHM is also connected geomorphically with the Wyoming Moraine of the Huron

Lobe, assigned a minimum age of 15.7 ± 0.2 cal ka BP (GSC-2213) (Gravenor and

Stupavsky, 1976). Both these moraines are interpreted to have been formed during the

Port Huron Readvance as pro-glacial Lake Whittlesey (another product of this advance) is thoroughly dated at ~15.4 cal ka BP (Barnett, 1979).

In addition to the date interpreted for the SLPHM, two hypothesized geomorphic events are used to constrain the retreat of the SL. The first of these events is the draining of pro-glacial Lake Maumee across the thumb of Michigan via the Imlay outlet (Figure

1.5). A single radiocarbon age from leaf materials is interpreted as a minimum age for the youngest stage of Lake Maumee draining through this outlet at 16.7 ± 0.6 ka cal BP (I-

4899), allowing water to flow along the ice margin and enter the Grand River Valley

(Burgis, 1970; Eshman and Karrow, 1985). This age has been supported by optically stimulated luminescence (OSL) dating shoreline sediment of a lower stage of Lake

Maumee dated at ~16.8 ± 1.0 ka (Fisher et al., 2015). This drainage 7

Figure 1.4. Ice flow direction and major moraines of the Laurentide Ice Sheet’s

Saginaw Lobe.

Figure 1.5. Drainage of pro-glacial Lake Maumee via the Imlay Channel near Imlay

City, MI. Drainage followed this route to the Grand River Valley and into Pro- glacial Lake Chicago (adapted from Eschman and Karrow, 1985). A radiocarbon age of 16.7 ± 0.6 cal ka BP from organics in a small channel called the Weaver Drain is associated with this event.

would require the SL’s margin to be within the Saginaw Lowlands, allowing water to flow in a proglacial position along its margin.

Another well documented, but not well constrained event which supports a rapid retreat of the SL is the Kankakee Torrent (Figure 1.6). First hypothesized by Ekblaw and

Athy (1925), the Kankakee Torrent is a large outburst flooding event from the Michigan,

Saginaw, and Huron-Erie lobes. Evidence of its flow is present in Illinois and Indiana and includes large streamlined bars, abandoned high-level channels and widespread rubble deposits. Similar features are seen in Michigan and associated with the Central

Kalamazoo River Valley, and attributed to subglacial flow from the Saginaw Lobe positioned at the Kalamazoo Moraine (Figure 1.4 on p. 18) (Kozlowski et al., 2005) or the Sturgis Moraine (Fisher and Taylor, 2002). Radiocarbon ages from Illinois related to the Kankakee Torrent provide a minimum age of 19.0 ka cal BP (Curry et al., 2014), placing the SL at the Kalamazoo Moraine at this time. Aside from radiocarbon ages associated with either the Imlay outlet within the thumb of Michigan, or the Kankakee

Torrent in Illinois, most radiocarbon ages from terrain once covered by the SL are younger than ages of deglaciation from regional deglacial reconstructions (Dyke, 2004).

1.4 Radiocarbon Ages from Inland Lakes and Deglacial Reconstructions

As demonstrated for the Saginaw Lobe, constraining the ages of retreat for ice lobes can be difficult, and this difficulty can stem from a scarcity of datable organics within glacial sediments. This scarcity has lead scientists to other sources of radiocarbon ages, such as bones of prehistoric megafauna or the organic rich mud of small inland lakes. Unfortunately, many dates derived from older bone collagen samples and bulk 10

Figure 1.6. Interpreted flow paths of the Kankakee Torrent (adapted from Curry et al., 2014).

samples of organic-rich mud are now known to be inaccurate age estimates which can be too young or too old (Grimm et al., 2009; Hedges et al., 1992). With the proliferation of accelerator mass spectrometry (AMS) radiocarbon dating, smaller organic samples (~1 mg) could be dated with great precision and bulk sampling could be avoided (Linick et al., 1989). As a result, the dating of small terrestrial macrofossils (wood, leaves, pine needles, etc.) was pursued. Today, terrestrial macrofossils found in inorganic units or lake sediment are desired in place of the organic-rich mud in lake basins and bogs for radiocarbon dating.

Frequently seen in deglacial reconstructions, basal ages from lakes and bogs have been used to provide minimum ages for ice free conditions, but how limiting these ages are is not well understood. In regions such as the path of the Saginaw Lobe, these ages are considerably younger than proposed ice marginal positions during deglaciation

(nearly 2,000 radiocarbon years in some cases). The presence of this temporal gap is mentioned in deglacial reconstructions, and explain through a time lag between deglaciation and the deposition of terrestrial macrofossils within these basins.

1.5 Melt-out Time Lags

Terrestrial macrofossils used for radiocarbon dating are often found in pebbly or sandy sediment underlying thick layers of lacustrine sediment within the basal units of lakes and bogs in formally glaciated regions (Florin and Wright, 1969; Derouin et al.,

2007; Glover et al., 2011; Blaszkiewicz, 2011; Horton, 2015; Slowinski et al., 2015). The origin of this basal sediment was first hypothesized by Florin and Wright (1969) and described as glacial fluvial outwash which covered previously buried ice blocks. After the ice melted, this outwash with trace organic material, was deposited at the bottom of the kettle basin (Figure 1.7). This same model can be applied to lake basins formed through subglacial flow (scour lakes), which are interpreted to have been inundated with ice after collapse of tunnel channels (Kehew et al., 2013). With the melt-out model proposed by Florin and Wright (1969) came the concept of a melt-out time lag, an estimated 1,000–5,000 year time span accounting for plant succession and the melting of buried ice which occurred before deposition of sandy basal sediment referred to as “trash layers.” 12

Figure 1.7. Transition from glacial to lacustrine landscapes for A) kettle lakes and

B) scour lakes.

This hypothesis has been cited as an explanation for young radiocarbon ages recovered from lakes and bogs in areas thought to have been deglaciated much earlier than these ages. The variability of this lag has been demonstrated across different regions (Birks,

1980; Derouin et al., 2007) and at more local scales (Blaszkiewicz, 2011). However, deglacial reconstructions often generalize this lag for large regions. For the region once covered by the Saginaw Lobe, basal radiocarbon ages are generally assigned a lag of

1,000–2,000 years (Fullerton, 1980; Mickelson, 1983; Dyke, 2004). However, a lag of a longer extent is documented in Illinois, where deglacial dates from basal radiocarbon ages in kettle lakes are ~4,000 younger than those from ice-walled lake plains (IWLPs) in 13

the same region (B. B. Curry personal comm., 2017). IWPLs are lakes within stagnant ice and their basal radiocarbon ages are interpreted to date the transition to a stagnant glacial margin (Curry and Petras, 2011).

Radiocarbon ages collected from lakes and bogs near the southern extent of the

Saginaw Lobe continue to post-date the lobes retreat. Two recent studies produced dates from basal sediments within lakes and bogs that suggest a slower retreat of the Saginaw

Lobe than previously proposed by regional reconstructions. Glover et al. (2011) collected radiocarbon dates from the basal sediments of lakes and bogs throughout Michigan,

Indiana and Ohio. Radiocarbon dates from her study agree with interpretations of retreat for the Huron-Erie Lobe, but in the interlobate region between this lobe and the Saginaw

Lobe they are younger than reconstructed ice-marginal positions. If interpreted as limiting minimum ages for the lobes’ retreat they suggest a more simultaneous retreat of both lobes. Similarly, Horton (2015) collected radiocarbon ages from lakes on the

Sturgis Moraine (Figure 1.3). These ages provide a minimum age for the moraine and local deglaciation of ~16.6 cal ka BP, >1,000 years younger than regional deglacial reconstructions (Fullerton, 1980; Dyke, 2004). Both studies suggest that a later retreat of the Saginaw Lobe from the tri-state region and the Sturgis Moraine is possible.

1.6 Sturgis Moraine

First identified by Leverett and Taylor (1915), the Sturgis Moraine was deposited by the Saginaw Lobe, located between the Shipshewana Moraine to the south, and the

Tekonsha Moraine to the north (Figure 1.4 on p. 16). The moraine has been interpreted to

be indicative of a terminus of a drumlin producing ice advance, with large alluvial fans extending from its margins, and crossing tunnel channels (Kehew, 2012). In addition, the presence of an interpreted proglacial outwash apron underlying the sediment of both the

Shipshewana and Sturgis moraines and ice-thrust complexes within both morainal ridges

(Figure 1.8) provide further evidence of a readvancing Saginaw Lobe (Fleming et al.,

1997). However, others have interpreted the moraine to be a product of deposition by subglacial meltwater at a stagnant ice margin (Fisher et al., 2005). The extensive drumlin field, tunnel channels, and eskers proximal to the moraine are offered as evidence of subglacial meltwater flow focused to the moraine (where these features cease). Thus, the

Sturgis Moraine is in a position where accurately assigning an age to it would allow for a better understanding of recession rates of the ice margin, interactions between adjacent lobes, and when drainage from ancestral Lake Erie drained across the Saginaw Bay

Lowlands. Radiocarbon dating along its margin by Horton (2015) suggested that either the moraine is younger than previously interpreted, or lakes in this area were subjected to a melt-out time lag of ≥2,000 years.

1.7 Deposition of Basal Trash Layers

The abundance of pebbly sand or sand bearing terrestrial macrofossils at the base of the sediment column within kettle lake basins has been primarily explain through one depositional model. Florin and Wright (1969) interpreted this basal sediment a product of down-wasting as ice melted with a lake basin and referred to this sediment as a “trash” layer. Down-wasting involves the movement of sediment downward without lateral

Figure 1.8. Stratigraphy of the Sturgis and Shipshewana moraines and surrounding area (modified from Flemming et al., 1997).

movement of adjacent slopes and has been associated with topographically negative features such as kettles (Schomaker, 2008). Occurring in the same environment is backwasting – a process where erosion of slopes leads to lateral migration of the slope. This method of mass wasting is associated with positive landforms such as ice-cored moraines

(Krüger and Kjær, 2000). Both processes can yield similar sediment units which have been observed in kettles in Poland in conjunction with deformational structures related to slumping (Blaszkiewicz, 2011).

Sediment moving downward onto ice from down- or back-wasting is referred to as supraglacial sediment and is commonly found on alpine glaciers (Eyles, 1979). When this covered ice reaches the ice margin and begins to melt, it can be reworked with sediment within the ice, undergo deformation, and be redeposited as a more dimictic sediment unit. This continued melting and deformation results in a massive, poorly sorted, sediment package susceptible to faulting and /or further deformation. This deposition is analogous to the movement and deposition of sediment above buried ice blocks.

Sediment covering abandoned ice undergoes similar depositional processes to supraglacial sediment through down-wasting – the interpreted primary mode of sediment movement as buried ice subsides within a close basin (Shomacker, 2008). In this model, sediment above buried ice would slowly move downward as ice melts and mix with lacustrine sediment collecting in the newly formed depression through internal slumping and slumping of the surrounding slopes. In this setting, the trash layer would consist of massive, poorly sorted, and deformed sediment with sources not limited to the supraglacial sediment. This sort of sediment is not similar to descriptions of basal trash layers by Florin and Wright (1969) and observations by other authors (Derouin et al.,

2007; Glover et al., 2011; Blaszkiewicz, 2011; Horton, 2015; Slowinski et al., 2015).

Thus, multiple modes of deposition must be considered to account for sandy basal sediment consistently found in lakes and bogs. These different depositional systems will be assigned a letter (A–E) for further discussion.

1.8 Depositional Systems in Post-glacial Landscapes

Depositional System A will refer to the deposition of basal trash layers as described by Florin and Wright (1969). This involves the down-wasting of sediment which covers abandoned ice into a lake basin as melting occurs. The sediment expected in this system is a massive, poorly sorted (diamicton) and deformed mixture of glaciolacustrine and glaciofluvial sediment which may be faulted.

Depositional System B is sedimentation following the melting of ice within a lake basin. At this stage, lake basins and their surrounding catchments would have remained in a paraglacial environment, susceptible to further mass wasting and sediment movement before vegetation moved in and provided stability (Ballantyne, 2002). Modes of deposition in this environment may have included gravity flows (debris flows) or under flows. Gravity flows are commonly associated with turbidity deposits, a product of turbulent flow resulting in graded beds (fining-up) at the bottom of an inclined surface

(Miall, 1978). Gravity flows are also capable of depositing massive sedimentary units, typically referred to as true debris flow or mudflow deposits (Walker, 1966; Myrow &

Hiscott, 1991). Differing from turbidity deposits, these deposits are massive, and often exhibit larger clasts (pebbles or gravels) suspended in finer muds as a result of cohesive flow (Lowe, 1984). Gravity flow deposits in smaller lakes have been observed following tsunamis or earthquakes, which lead to transportation and deformation of sediment in and around lakes (Kempf et al., 2015; Sasaki et al., 2016; Kempf et al., 2017), but minimal research has been conducted in recently deglaciated environments.

Depositional System C is a fluvial system. Fluvial systems are another alternative method of transport that could transport allochthonous sediment into a kettle lake basin. 18

Geomorphic evolution in a paraglacial landscape has been shown to produce networks of kettle lakes connected through streams/rivers (Slowinski et al., 2015). Fluvial flow disrupts the deposition of finer lacustrine sediment, creating a sharp contact between mud or organic sediment and fluvial deposits such as sand and gravel. Once sediment entered the lake basin it would effectively act as gravity flows, depositing massive units of fine pebbles to muds in planar beds or subaqueous fans (Miall, 1978; Slowinski et al., 2015).

Sediment deposited in this sort of alluvial system would exhibit stratification and sorting, unlike the depositional systems previously discussed.

Depositional System D is an aeolian system. Sediments of any grain size from granules to clay can be transported by winds depending on its velocity. In small lakes such as kettles, aeolian deposits are typically characterized by laminations or larger units of well sorted sands or silts (loess) and are interpreted to mark climatic aridity or changes in vegetation (Lagerbäck and Roberstsson, 1998; Almquist-Jacobson et al., 1992).

Expected sedimentary structures would be grain-fall laminations, regardless if water was present in the lake basin (Hunter, 1977). In these deposits, sediment grains fall from suspension due to a drop in wind velocity, or their submergence in water. The resulting sediment is deposited in planar beds that can be faint or well defined. Grains size in these bed would be dependent on wind velocity.

Depositional System E is a littoral system. Deposition of sediment on and near the shore of a lake are dominated by waves and longshore currents. In small lakes, longshore currents are only observed in elongated lakes that are exposed to steady winds, thus wave action alone likely contributes most of the reworking in small lakes such as kettles. This wave and current action reworks sand and pebbles on shore and removes finer sediment, 19

transporting silt and clay to deeper water resulting in planar beds of pebbly sand (Cyr,

1997). Within inland glacial lakes, lake levels (groundwater tables) are inferred to have risen after deglaciation, resulting in submergences of shorelines. Sediment sequences corresponding to these regressions in large lakes (such as the great lakes) exhibit cross- bedded units of sand with erosional lower contacts representative of nearshore, backshore, and overwash (storm events) deposition (Thompson, 1989).

1.9 Objectives and Hypothesis

The objective of this study is to test the 2,000 year melt-out time lag applied to lakes associated with the Sturgis Moraine and throughout the region once covered by the

Saginaw Lobe of the Laurentide Ice Sheet. The basal trash layer hypothesis will be examined as the model of deposition for sandy terrestrial sediment found within kettle lake basins. Basal radiocarbon ages and stratigraphy from a series of lakes from different ice-marginal positions along the Sturgis and Shipshewana moraines will be obtained by coring. Results from these lakes will be compared to those from lakes within abandoned tunnel channels of the Sturgis Moraine (Horton, 2015) to determine the variability in local lake stratigraphy and basal ages. To complement the radiocarbon dating, OSL dating of basal sand units and pollen analysis will be conducted to better constrain the depositional ages of these lakes’ basal trash layers.

The hypothesis to be tested: Inland lakes in the region surrounding the Sturgis

Moraine experienced a similar melt-out time lag which delayed the deposition of basal trash layers. This deposition occurred in the manner described by Florin and Wright

(1969). 20

Chapter 2

Methodology

2.1 Introduction

To complete the objectives of this study, lacustrine sediment was collected from six different lakes along two moraines. This sediment was examined with physical, biological and geochemical analyses, and dated using two different methodologies. The procedures and analysis included: 1) collection of sediment with a Livingstone corer; 2) scanning of cores using X-ray tomography (CT) scanner at the University of Toledo

Medical Center; 3) processing, splitting, photographing and describing cores at the

Limnological Research Center (LRC) at the University of Minnesota, Minneapolis, MN;

4) magnetic susceptibility; 5) collection of terrestrial macrofossils for radiocarbon dating;

6) loss-on-ignition; 7) grain-size analysis; 8) carbon/nitrogen ratios conducted by the

United States Department of Agriculture (USDA); 9) pollen analysis conducted by Dr.

Francine McCarthy at Brock University, St. Catharines, ON; and 10) optically stimulated luminescence (OSL) dating of basal sand by Dr. Ken Lepper at North Dakota State

University, Fargo, ND.

2.2 Lake Selection and Coring

Lakes were chosen for coring based on their position in reference to the central margin of the Sturgis Moraine and their inferred geomorphic environment of formation.

Kettle lakes down- and up-ice of the Sturgis Moraine were cored (Bullhead, Meteer, and

Thompson lake) in addition to a scour lake (Fish Lake) within an abandoned tunnel channel. Further down ice, two lakes (Stone and Hunter lake) on either side of the

Shipshewana Moraine’s margin were also cored. Up ice, two lakes (Lanes and Winnipeg lake) along the margin of the Kalamazoo Moraine were also cored. Locations of lakes are shown on a digital elevation model in Figure 3.1.

For each lake, three sediment cores were sampled using a Livingstone Corer

(Wright, 1991) with a hydraulic assist. The coring platform was a custom built canoe catamaran or modified pontoon boat (R.V. Perforator). Locations for coring within lakes were selected based on lake bathymetry, specifically where steeper gradients terminated near the deepest pools within the basin. At the base of these slopes, terrestrial macrofossils falling into the lake would have come to rest. Geographic coordinates, weather conditions and time were recorded at each core location. An initial sediment core

(A) was then extracted in one-meter sections and extruded directly into a split piece of

PVC tube. The coring device was then reinserted into the same hole to retrieve the next meter of sediment. Once basal sediment and refusal (jacking up the coring platform after encountering inferred gravels and other larger clasts) was reached a second core (B) was taken approximately one meter away at a starting depth 0.5 meters deeper than the previous core for overlap with emphasis of the lower core sections. A third core (C) was then taken one meter further away to obtain a single core section just above refusal and 22

directly extruded into black PVC (ABS) for OSL dating of basal sand. Cores extruded into split PVC were measured, briefly described, wrapped in plastic wrap, and then sealed in PVC for transport. All core sections were labeled with core identification and the date before the next core was extruded. Cores were stored in the department’s 4°C cooler to maintain their structure and their viability for radiocarbon dating.

2.3 X-ray Computed Tomography

Unprocessed cores were sent through a X-ray computed tomography (CT) scanner at the University of Toledo Medical Center. CT scanning produce images displaying changes in density through lower sediment core sections and were color coordinated to use the same color scheme for all cores.

2.4 The Limnological Research Center (LRC), Minneapolis, MN

Basal sediment core sections from all five lakes were transported to the

Limnological Research Center (LRC) at the University of Minnesota, Minneapolis, MN.

Core sections were placed in a cradle apparatus and split with fishing line. Section halves were labeled as either an archive or working half. Working halves were immediately cleaned and imaged with a line-scan CCD camera to produce one seamless color image of each core section. Archive halves were re-sealed in plastic wrap and stored until their return to the University of Toledo.

Sediment from working halves were described by content, structure and Munsell color on initial core description (ICD) sheets. Some cores displayed discoloration from oxidation, inferred to be a consequence of long periods of storage. 23

High resolution magnetic susceptibility (MS) measurements were recorded with a

Bartington point sensor (MS2E) mounted within a Geotek MSCL-XYZ automated core logger in 0.5 cm intervals. Cores were covered with a plastic film placed directly on the sediment’s surface to avoid direct contact with the 1 cm diameter sensor. Magnetic susceptibility is an indicator of flow energy with higher MS values recording higher energy depositional environments (Dearing, 1999).

2.5 Grain Size Analysis

Grain size was determined throughout basal core sections with a Mastersizer 2000 laser diffraction system with a Hydro 2000UM dispersion unit. Samples containing >2%

CaCO3 were treated with sodium acetate, and those with >3.5% organic C were treated with H2O2 to reduce organic particulate matter within samples. To promote dispersion of sediment, samples were soaked in a 4% sodium hexametaphosphate (deflocculant) solution for 24 hours. More detailed methods involving sample pre-processing can be found in Bobak (2001). Prepared samples were then introduced into the dispersion unit in

~800 mL of deionized (DI) water. Details of the grain-size analysis process can be found in Malvern Instruments (1998). Three repeat measurements of particle size were recorded and averaged. This average was then enter into an excel workbook where raw data was converted into percent sand, silt or clay based on the Unified Soil Classification System

(USCS).

2.6 Loss-on-ignition

Loss-on-ignition (LOI) provides an estimate of organic C and CO3 in lake sediment (Heiri et al., 2001). A 1 cm3 sample was taken every 2 cm within the lowest core section from each lake. Samples were weighed, dehydrated at 110°C, and weighted again to remove and estimate water content. Dry samples were heated to 550°C and weighed to approximate percent-loss of mass due to ignition of organic C. After cooling, samples were heated to 1000°C and weighed to estimate percent-loss of mass due to ignition of CaCO3.

2.7 Carbon/Nitrogen Ratios

Ratios of organic C and N were measured in the USDA Agriculture Research

Service (ARS) laboratory at the University of Toledo through high temperature combustion with a vario MIRCO cube CN analyzer by Elementar. A series of twenty-five samples in 1 cm intervals were collected from the lowest core section of each lake. This series spanned the lower basal contact between organic and inorganic sediment. Samples were then prepared in the ARS lab for combustion analysis. C/N ratios are an environmental proxy for sources of organic material within lacustrine basins (Meyers and

Ishwatari, 1993; Hassan et al., 1997; Meyers and Verges, 1999). Ratios of ≥20 record vascular plant tissue, 4–10 record phytoplankton, and ratios of 10-20 indicate a mixture of the two (Meyers and Verges, 1999).

2.8 Radiocarbon Dating

Radiocarbon dating by accelerator mass spectrometry (AMS) of terrestrial macrofossils was used to constrain the age of deposition for the basal sediment within each lake. Sediment within the lowest core sections was wet sieved in 1 cm increments beginning at the base of the core to collect the sample at the lowest stratigraphic position possible (inferred to be oldest). This process continued until suitable macrofossils (wood, twigs, or needles) were collected, which was confirmed by examination under a microscope. Terrestrial material was then dried at 110°C and weighed. Samples that met the mass criteria of 1.0 mg were then placed in plastic vials for storage in a 4° cooler to prevent carbon contamination by modern carbon. Special care was taken to avoid any contact with carbon samples so that contamination did not occur. Gloves were always worn when handling samples and vials. One carbon sample from each lake was sent to the National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS) at the

Woods Hole Oceanographic Institution, Woods Hole, MA, for AMS analysis.

2.9 Pollen Analysis

Pollen analysis was used to determine the local vegetation surrounding the lake basin after the lake had become biologically productive. Records of different pollen could then be compared to other sites to offer insight into the approximate timing of sediment deposition. Samples (n=11) were collected from sediment above the basal contact of three lakes (Fish, Hunter, and Thompson) and also from Wall Lake. Wall Lake was cored and examined by Horton (2015). Samples consisted of 3–5 cm3 of sediment and were placed in individual whirl packs and labeled based on their core section ID and depth. 26

Samples were sent to Brock University, St. Catharines, ON, Canada for analysis by

Francine McCarthy, PhD. Dr. McCarthy was not informed of each samples stratigraphic context or related radiocarbon age to allow for unbiased interpretation of observations.

Samples were identified using the key of McAndrews et al. (1973). Age estimates for the deposition of sediment units where obtained by comparing assemblages to thoroughly studied regional lakes including: Appleman Lake, Indiana (Gill et al., 2009), Crystal

Lake, Illinois (Gonzales and Grimm, 2009), and Silver Lake, Ohio (Gill et al., 2012).

2.10 Optically Stimulated Luminescence Dating

Optically stimulated luminescence dating was used to determine the approximate time at which basal sands were deposited within each lake basin. When possible, multiple samples were taken from the same sediment unit to improve result quality. This method provides an age that marks the last time sand-sized sediment grains were exposed to sunlight (Aitken, 1998). The amount of exposure sediment had to light (bleaching) could also be useful in determining the depositional environment of sampled sand. With fluvial, aeolian, and littoral systems speculated as possible depositional environments, sand grains may have been sufficiently exposed to light for bleaching or partial bleaching.

However, if OSL dates record extremely old dates (> MIS 2), this information could still be useful regarding the interpretation of depositional environments. Once basal sediment was retrieved in coring, a separate core section was extruded directly into black PVC

(ABS). These black pipes protected sand from sun light exposure, maintaining its viability for OSL dating. Sediment cores within ABS were sealed and sent with inferred

stratigraphy to Kenneth Lepper, PhD at North Dakota State University, Fargo, ND for processing which followed procedures established by Lepper et al. (2007).

Chapter 3

Results

3.1 Introduction

Eight lakes were targeted for coring (Figure 3.1). Two to three cores from each lake were extracted from each of the six lakes targeted along the Sturgis and

Shipshewana moraines (Figure 3.2. Neither basal sediment nor refusal was reached in both lakes associated with the Kalamazoo Moraine, and thus they are not included in any stratigraphic analysis. Analysis and description of basal sediment (lower 1–2 meters) was emphasized to thoroughly characterize and evaluate the potential depositional environments of each lake’s inferred trash layer. Sediment above these sections was either not collected or not examined in detail, leaving descriptions of this sediment to be limited to observations in the field. All radiocarbon, OSL, and pollen analysis is from the lower core sections.

3.2 Lake Stratigraphy

Stratigraphy of each lake was documented with emphasis on the lowest core section. These sections are displayed in Fig. 3.4, .6, .8, .10, .12, and .15. Classification of

Figure 3.1. Lakes selected for coring along the Kalamazoo, Sturgis, and

Shipshewana moraines.

Figure 3.2. Lakes and coring positions with surrounding topography. A) Thompson,

B) Fish, C) Bullhead, D) Meteer, E) Hunter, and F) Stone. 31

sediment followed Schnurrenberger (2003). Each of the figures includes a series of three images; A) a high-resolution core photograph, B) a computerized-tomography (CT) generated image of density, and C) a sediment facies column. These images are displayed with particle size, magnetic susceptibility (MS), carbon/nitrogen ratio (C/N), and loss-on- ignition data from left to right. In the figures for Thompson and Stone Lake, C/N values are capped at 1500 and 800 respectively due to extremely high values. A legend supporting these figures is shown in Figure 3.3.

3.2.1 Thompson Lake

Thompson Lake (Figure 3.1 and 3.2) is a kettle lake within the outwash fan of the

Sturgis Moraine and the largest lake cored in this study. Its basal stratigraphy (Figure 3.4) consists of 6 sediment units. Unit a is a 25 cm thick, massive, coarse–medium, pebbly sand (Figure 3.5) with an unknown lower contact due to refusal. This sand exhibits MS values from 20–120 SI which peak just before its upper contact, C/N ratios of >500, <2% organic carbon, and 6─10% carbonate. Unit b is a 13 cm thick, massive, sandy silt with a sharp, flat, lower contact. MS values drop to <2 SI with C/N ratios >600, <2% organic carbon, and ~42% carbonate. A pollen sample was collected from this unit, but no assemblage from comparison sites matched the pollen assemblage of the sample. Unit c is a massive pebbly sand unit 5 cm thick, with a sharp, flat lower contact with similar analytical values to unit a. Two OSL samples from this unit were dated to 19.0 ± 0.8 ka and 20.4 ± 1.4 ka at 1σ. Unit d is a 78 cm thick brecciated unit with an angular and erosional (2–3 cm) lower contact. It consists of clasts of pebbly sand, sandy silt, and mud

Figure 3.3. Supported legend for Figures 3.4, .6, .8, .10, .12, and .15 of basal lake stratigraphy. 33

*FS: Fine Sand, MS: Medium Sand

Figure 3.4. Stratigraphy and chronology of Thompson Lake’s lower core section. 34

Figure 3.5. Particle size distribution of Thompson Lake’s Unit a.

with no apparent internal structure to the clasts. MS values fluctuate between ~0–25 SI, and C/N values are all >500. Organic carbon is <3% and there is 10–42% carbonate. In an adjacent core, a wood log was intercepted at 8.59 m and dated to 15.0 ± 0.1 cal ka BP.

Unit e (not shown in figure) is a continuous sequence, which extends to the top of sediment with a thickness of 8.14 m, of carbonate mud with fine (< 1mm) laminations in some sections. MS values are low (< 5 SI), organic carbon is < 2% with 20–30% carbonate in the first 0.7 m of this unit.

3.2.2 Fish Lake

Fish Lake (Figure 3.1 and 3.2) is an elongated scour lake within an abandoned tunnel channel of the Sturgis Moraine. Its basal stratigraphy (Figure 3.6) contains 5 units.

Detailed particle size data is shown for Units a–d in Figure 3.7. Unit a is 11 cm thick, crudely laminated, poorly sorted, coarse–fine sand with an unknown lower contact due to refusal. This unit exhibits MS values 7–15 SI, < 5% organic carbon, and 3–22% carbonate. A wood fragment within this unit at 2.82 m was radiocarbon dated to 16.2 ±

0.1 cal ka BP. Unit b is an 8 cm thick, massive, sandy silt with a sharp, erosional lower contact. MS range from 10–40 SI, CN is >100, organic carbon remains low (<5%) and carbonate ranges from 8–28%. Unit c is 12 cm thick, coarse–medium pebbly sand with a gradational lower contact. The coarse sand has MS values from 33–134 SI increasing up core. C/N remains >100, organic carbon is <2%, and carbonate is between 2–10%. Unit d is a faintly laminated, 10 cm thick, sandy silt with a sharp, flat, lower contact. MS values are lower (20–45 SI) than unit c. The C/N is >100, organic carbon is <3%, and carbonate accounts for ~10%. A sample of this unit was dated 9.9 ± 0.3 ka with OSL. Unit e is a carbonaceous mud (sapropel) which continues to the top of sediment for 2.45 m with a gradational lower contact. MS values are ~20 SI, C/N drops dramatically to ~14, organic carbon ranges from 17–30%, and carbonate is low (<4%) in the first 0.53 m. Within the

CT scan, ~4 cm laminations of lower density mud can be observed. At 1.93 m, a 1 cm thick silt lamination interrupts this mud. Three pollen samples at 1.91 m, 2.38 m, and

2.43 m recorded deposition after 8.0 ka and were dominated by Quercus, Pinus, and

Ulmus.

Figure 3.6. Stratigraphy and chronology of Fish Lake’s lower core section. 37

Figure 3.7. Particle size distribution of Fish Lake’s Unit a.

3.2.3 Bullhead Lake

Bullhead Lake (Figure 3.1 and 3.2) is a kettle lake within the hummocky terrain of the Sturgis Moraine. The basal stratigraphy of Bullhead Lake (Figure 3.9) consists of 4 sediment units. Unit a is 23 cm of interbedded coarse–medium sand and sandy silt (Fig.

3.9) (some beds are angular) with an unknown lower contact due to refusal. MS values are higher with depth, and range from 1–5 SI. CN ratios fluctuate from 26–69, organic carbon is <4%, and carbonate is <1%. Sand in this unit at 2.58 m recorded an OSL age of

Figure 3.8. Stratigraphy of and chronology Bullhead Lake’s lower core section. 39

12.7 ± 0.3 ka, and a wood fragment at 2.58 m was radiocarbon dated to 13.4 ± 0.05 cal ka

BP. Unit b is a massive, 15 cm thick, silty and clayey sand with a gradational, angular lower contact. MS values are 3–6 SI, C/N ranges from 32–56, organic carbon increases from 3–13%, and carbonate is <2%. Unit c is a laminated, 20 cm thick, carbonaceous mud with a sharp, undulating lower contact. MS values are <4 SI, C/N drops to 15–20, organic carbon continues to rise from13–30%, and carbonate remains low (<3%). Unit d is a 2.34 m thick herbaceous peat over with a gradational lower contact of ~10 cm which exhibits MS values ~0 SI, higher organic carbon (>50%), and <2% carbonate in the first

0.27 m. The lower contact is only visible in image produced by CT scanning.

Figure 3.9. Particle size distribution of Bullhead Lake’s Unit a. 40

3.2.4 Hunter Lake

Hunter Lake (Figure 3.1 and 3.2) is kettle lake within the hummocky terrain of the

Shipshewana Moraine. Hunter Lake’s basal stratigraphy (Figure 3.10) consists of 3 sediment units. Unit a is a 26 cm thick, massive, pebbly, medium sand (Figure 3.11) with an unknown lower contact due to refusal. MS values are 12–165 SI with the highest values in the first 10 cm. Organic carbon is low (<4%) and carbonate is 2–6%. A radiocarbon sample at 5.32 m was dated to 16.0 ± 0.1 cal ka BP. Two OSL samples from this unit were dated to 14.4 ± 0.5 ka and 14.8 ± 0.7 ka. Unit b is a massive, 8 cm thick, sandy silt which exhibits normal grading from sand to silt with a gradational lower contact over 1–2 cm. MS values range from 9–29 SI, C/N drops dramatically from >100 to ~23, organic carbon is 5–10%, and carbonate is ~5%. Wood was sampled at 5.06 m and radiocarbon dated to 16.0 ± 0.1 cal ka BP. Unit c is a massive, 5.07 m thick, clayey silt (mud) with a sharp, flat lower contact. MS values range from 10–25 SI, C/N is 21–25, organic carbon fluctuates but never exceeds 10%, and carbonate remains ~5% in the first

0.38 m. Pollen samples at 4.82 m and 5.02 m both record deposition between ~16.0–14 ka with pollen assemblages dominated by Picea.

3.2.5 Stone Lake

Stone Lake (Figure 3.1 and 3.2) is another kettle lake within the hummocky terrain of the Shipshewana Moraine. Stone Lake’s basal stratigraphy (Figure 3.12) consists of 3 sediment units. Unit a is crudely laminated, 15 cm thick, coarse-medium sand interbedded with sandy silt (Figure 3.13). This interbedded unit’s lower contact is

*FS: Fine Sand, MS: Medium Sand

Figure 3.10. Stratigraphy of and chronology Hunter Lake’s lower core section. 42

Figure 3.11. Particle size distribution of Hunter Lake’s Unit a.

unknown due to coring refusal. MS values are 3–53 SI, C/N is highly variable with some values >1000, organic carbon is <2%, and carbonate is 5–22%. Two OSL samples from this unit were dated to 23.2 ± 1.0 ka and 23.6 ± 1.1 ka. Unit b is a 20 cm thick, sandy silt with a gradational lower contact. MS values increase up core (5–95 SI), C/N is >500, organic carbon accounts for <3%, and 7–31% is carbonate. A needle recovered at 4.84 m was radiocarbon dated to 16.0 ± 0.1 cal ka BP. Unit c is a 56 cm thick, clayey silt with a gradational lower contact with a mixed internal stratigraphy visible on the CT scan. MS

*FS: Fine Sand, MS: Medium Sand

Figure 3.12. Stratigraphy and chronology of Stone Lake’s lower core section. 44

values display high and low trends (17–109 SI), C/N ratios are variable (>200), organic carbon remains low (<4%), and carbonate is ~20%. Abundant charophyte stems were observed in all three units (Figure 3.14).

Figure 3.13. Particle size distribution of Stone Lake’s Unit a.

3.2.6 Meteer Lake

Meteer Lake (Figure 3.1 and 3.2) is a kettle lake within the outwash fan of the

Sturgis Moraine. Meteer Lake’s basal stratigraphy consists of two units (Figure 3.15).

Unit a is an 18 cm thick pebbly, coarse–medium sand with an unknown lower contact due to refusal. Organic carbon is <1% and carbonate is <4%. Wood recovered from this

unit was radiocarbon dated to 16.2 ± 0.1 cal ka BP. Unit b is a 105 cm thick brecciated unit containing peat, carbonaceous mud and carbonate mud. Organic carbon ranges from

7–63% and carbonate from 3–28% within brecciated clasts. Clasts are both angular and rounded, varying in size. This brecciated sequence has a sharp, undulating lower contact.

Figure 3.14. Charophyte (green algae) stems from Stone Lake’s sediment units.

3.3 Facies Descriptions

Due to commonalities between sediment types in the six lakes described previously, sedimentary units are grouped into one of five sediment facies (A˗E) (Figure

3.16).

Facies A is a single, or a series of pebbly sand to silt units. These units are either massive or faintly laminated. In lakes where multiple units are present, lower contacts can be flat or angular, sharp or gradual. Sediment contains trace to abundant terrestrial

Figure 3.15. Stratigraphy and chronology of Meteer Lake’s lower core section. 47

Figure 3.16. Depths, lithofacies, and chronology of cored lakes along the Sturgis and

Shipshewana moraines.

macrofossils (plant debris and wood). MS values are typically highest in this facies, but are variable (1–165). Organic carbon is <5%, carbonate is between 5–40%, and C/N ratios exceed 30, but in many cases are >100. The lower contact is unknown as this is the lower-most facies recovered before coring refusal occurred, where coring was suddenly stopped and the coring platform was raised by impact with presumably larger sediment clasts (boulders and gravel) or highly cohesive sediment (diamicton).

Facies B is clayey silt (mud) with carbonate, fluctuating in median grain size between silt and clay. A sharp lower contact is observed between this facies and Facies A or D. Organic carbon is <5%, but carbonate is 5–45% by mass. Magnetic susceptibility is

<25 SI, and nitrogen is nearly absent, resulting in high C/N ratios (>60).

Facies C is carbonaceous sediment that is primarily silt with increasing clay percentages up core. Organic carbon is between 10–40%, and carbonate is <5%. MS is

<20 SI. C/N ratios are 20–40. A gradual lower contact over 1–2 cm is present between this facies and facies A.

Facies D is a brecciated group of sediments composed of facies A, B and/or C found only in Thompson and Meteer Lake. Sharp contacts exist between this facies and

Facies A, but distinguishing between large clasts of brecciated sediment and separate sedimentary units is uncertain. Organic carbon and carbonate are variable, ranging from

3–65% and 5–42% respectively, which is expected from the varying sediment units sampled. From Thompson Lake MS values are irregular (~0–70) and C/N values are high

(>500).

Facies E is herbaceous peat, and is only found in Bullhead Lake. Plant fragments are visible and organic carbon approaches 80%. Magnetic susceptibility and carbonate 49

are nearly zero, and C/N ratios are <20. The lower contact is gradational across 10 cm from facies C to E. Due to high percentages of organic carbon, particle size was not attempted for this facies.

3.4 Chronology

Radiocarbon dating, optically stimulated luminescence (OSL) dating, and pollen stratigraphy were used to determine the chronology of basal sedimentary units. Sampling positions are displayed in Figures 3.4-3.15 and their ages are summarized for all lakes in

Figure 3.16. Each of the lakes was sampled for at least one radiocarbon age in the lowest possible stratigraphic position. One OSL age from basal sands was also recovered in all lakes except Meteer. Samples for pollen identification were collected from Thompson

(n=3), Fish (n=3) and Hunter (n=3) lakes.

3.4.1 Radiocarbon Dating

Seven radiocarbon dates (one from the basal section of each lake) are presented in

Table 3.1. In all cases, a single terrestrial macrofossil (wood fragment or pine needle) was dated. Four of the six lakes share a basal median radiocarbon age of 16.0–16.2 cal ka

B.P., with the other two basal radiocarbon ages being >1.0 ka younger. These ages are maximum ages for lake formation, assuming lacustrine sediment is not present beyond refusal, and the initial deposition of organic bearing allochthonous sediment into the lake.

Table 3.1. Radiocarbon age data.

Mean Probabillity Lab Number Material UT Lab ID δ13C 14C yr BP Age Error 2σ Range (cal yr BP) OS-127628 Plant/Wood HLK16-1B-1465 -25.37 13,300 ± 50 16,000 16,280-15,700

Beta-463205 Plant/Wood HLK41217 -24.8 13,290 ± 40 15,980 16,157-15793

OS-127629 Plant/Wood TPLK16-1A-1796 -24.3 12,600 ± 45 14,830 15,250-14,400

OS-127630 Plant/Wood BHLK16-1B-582 -23.6 11,550 ± 40 13,410 13,580-13,240

OS-127631 Plant/Wood FLK16-1A-1348 -27.18 13,450 ± 50 16,200 16,520-15,880

OS-127632 Plant/Wood SLK16-1A-1353 -27.15 13,300 ± 55 16,000 16,300-15,670

OS-122367 Plant/Wood MLK15-1A-1130 -24.63 13,450 ± 75 16,200 16,650-15,750

3.4.2 Optically Stimulated Luminescence Dating

One OSL age was collected from all lakes aside from Meteer Lake. Ages and related laboratory and dosimetry data are presented in Table 3.2. Ages record when sand was last exposed to sufficient sun light for bleaching and are maximum ages for initial deposition of allochthonous sediment into the lake. OSL measurements were made on the

150-250 μm grain size and 250-355 μm grain size fractions. Dose rates were calculated by sampling from sediment units above and below the unit to be dated. This additional sampling also helped to estimate the total amount of organics, which can store radioactive elements and impact OSL age calculations (personal communication with Kenneth

Lepper, 2017). Additional information regarding calculated dose rates and modeled dose rates components for OSL samples can be found in Table A of Appendix F. Equivalent dose distributions obtained from samples from Hunter Lake, Fish Lake, Stone Lake, and

Bullhead lake were all symmetrical (M/m < 1.05), indicative of well bleached grains.

Samples from Thompson Lake are not symmetrical (M/m >1.05), suggesting grains were 51

partially bleached, resulting in higher standard error values in age estimates. Ages throughout this study will displayed as: “Mean Age” ± “std. err. (Uncert.)” for all OSL ages as calculated by K. Lepper. Mentions of standard error to 1 σ will reference Table

3.2.

Table 3.2. OSL ages and related data.

Equivalent Dose Dose Rate Age c Uncert.d Lake Sample ID Grain size a Nb M/m (Gy) (Gy/ka) (ka) (ka) Dose rates from sample horizon only Hunter UT1605 FS 90/95 0.97 13.383 ± 0.442 0.931 ± 0.084 14.4 ± 0.5 1.4 Hunter UT1605 MS 91/96 0.99 13.282 ± 0.611 0.897 ± 0.080 14.8 ± 0.7 1.5 Stone UT1606 FS 91/96 1.04 17.458 ± 0.784 0.753 ± 0.063 23.2 ± 1.0 2.2 Stone UT1606 MS 87/96 1.02 17.100 ± 0.791 0.725 ± 0.060 23.6 ± 1.1 2.2 Dose rates from modeled stratigraphy with volume fraction contributions determined using geometric approximation Thompson UT1607 FS 93/96 1.08* 14.640 ± 0.652 0.769 ± 0.089 19.0 ± 0.8 1.8 Thompson UT1607 MS 91/96 1.05* 15.058 ± 1.003 0.737 ± 0.085 20.4 ± 1.4 2.2 Fish UT1608A FS 95/96 1.03 10.769 ± 0.282 1.091 ± 0.209 9.9 ± 0.3 2.5 Bullhead UT1609A FS 93/96 1.04 16.935 ± 0.368 1.335 ± 0.135 12.7 ± 0.3 3.3 a Grain size fraction sampled. Fine sand (FS); 150─250 μm, Medium sand (MS); 250─355 μm. b Number of aliquots used for OSL De calculation / no. of aliquots from which OSL data was collected (filtering criteria given in Lepper et al., 2003). c Mean and std. err. for symmetric samples (M/m < 1.05); *Leading edge analysis for positively asymmetric samples (M/m > 1.05; see supplement to Lepper et al., 2007). d Presented as calculated OSL age ± std. err. (uncertainty) at 1 σ

3.4.3 Pollen

Pollen analysis provided eight age estimates for sediment within three of the cored lakes (Table 3.3). In addition, two pollen age estimates were obtained for Wall

Lake (WLK) previously cored by Horton (2015). Age estimates were assigned by Dr.

McCarthy from comparison of pollen assemblages to those found in Appleman Lake,

Indiana (Gill et al., 2009), Crystal Lake, Illinois (Gonzales and Grimm, 2009), and Silver

Lake, Ohio (Gill et al., 2012). Five of these ten samples contain spruce dominated pollen assemblages consistent with a pollen zone spanning 16–14 ka BP from sediment directly 52

above basal trash layers. Samples from Fish Lake (FLK) recorded mesic conditions in all three samples consistent with pollen zones of the early Holocene (<8 ka). The lowest sample collected from Thompson Lake (TPLK) has no close analog with any of the three reference lakes, being dominated by Pinus with common Quercus and Ulmus. Detailed breakdown of pollen counts and taxa are available in Appendix G.

Table 3.3. Pollen age estimates and associated data.

Sediment Lake Sample ID Dominant Taxa Age Estimate Depth (m) Thompson TPLK1 9.01 Pinus N/A Thompson TPLK2 8.28 Picea 16–14 ka Thompson TPLK3 8.13 Quercus < 11 ka Fish FLK1 1.91 Quercus, Pinus, Ulmus ≤ 8 ka Fish FLK2 2.38 Quercus, Pinus, Ulmus ≤ 8 ka Fish FLK3 2.43 Quercus, Pinus, Ulmus ≤ 8 ka Hunter HLK1 4.82 Picea 16–14 ka Hunter HLK2 5.02 Picea 16–14 ka Wall WLK1 9.60 Picea 16–14 ka Wall WLK2 9.74 Picea 16–14 ka

Chapter 4

Interpretations

4.1 Introduction

Depositional environments for each facies are interpreted based on sediment characteristics, analytical data, and chronology. Chronological data from cores is also used to interpret the timing of depositional and erosional events within the lakes. From these interpretations, estimation of the ages for deposition of the Sturgis and

Shipshewana moraines, and deglaciation in the region are assigned.

4.2 Depositional Environments

Some sedimentary facies described in Section 3.3 are assigned a depositional environment, while others are given multiple potential interpretations. Emphasis is given to Facies A and D, which are similar in stratigraphic position to basal trash layers described by Florin and Wright (1969).

4.2.1 Facies A: Basal Sand

With observations of single or multiple, angular or planar, massive, faintly laminated or graded, pebbly sand to silt units, Facies A is interpreted as allochthonous sediment (originating from the basin’s surrounding catchment) which was brought into the lake through fluvial action, aeolian activity, and/or reworking from littoral action (i.e.

Depositional Systems C–E discussed in Section 1.8). These planar, primarily pebbly sand units are consistent with facies models of alluvial deposits from sediment gravity flows

(Miall, 1978) and also with an alluvial phase in a kettle interconnected with a fluvial stream (Slowinski et al., 2015). This interpretation is further supported by this facies’ greater MS values consistent with higher energy flow and a terrestrial origin (Dearing,

1999), and extremely high C/N ratios (>100) indicative of terrestrial sources of carbon and nitrogen (Meyers and Lallier-Verges, 1999). However, finer sand and silt units could also be explained through aeolian activity, where wind blew loose sediment into the lake, where it accumulated by suspension settling (Hunter, 1977; DeVries-Zimmerman et al.,

2014; Hanes et al., 2014). In addition, reworking of sandy sediment by littoral action is also a possible explanation for the sorted sands, but is not interpreted to have persisted for long periods of time due to a lack of crossbedding and other structures associated with littoral deposits (Thompson, 1989).

In Fish Lake deposition took place in a series of unique depositional environments, resulting in multiple well sorted pebbly sand to silt sediment units with sharp lower contacts (Figure 3.6). Units a and c are interpreted to be deposited through gravity flows with potential reworking by littoral action due to their grain size (coarse- medium sand with pebbles) and the elongated shape of Fish Lake, making it more 55

susceptible to littoral action resulting from steady wind. Alternatively, units b and d exhibit finer sand and silt, more consistent with weaker fluvial action and/or sediment falling out of suspension during aeolian activity. Basal sands of Thompson and Meteer

Lake consist of massive, pebbly, coarse-medium sand units, which are characteristic of a single debris flow deposited during fluvial action (Miall, 1978). In Bullhead and Stone

Lake one flow is also interpreted, but faint laminations within sand suggest varying flow velocity. Facies A in Hunter is interpreted as a single event of fluvial action as well, but the normal grading (transition from coarser to finer sediment up core) of the facies suggests a gradual termination to flow or a turbidity flow (Miall, 1978).

4.2.2 Facies B: Lacustrine Mud with Carbonate

Thick sequences of silt-dominated sediment with carbonate contents of ~15–40% by mass identified as Facies B are interpreted as a lacustrine carbonate mud deposit recording carbonate precipitation from groundwater upwelling (Schnurrenberger et al.,

2003). Charophyte (green algae) stems were observed in this facies in Stone Lake, an indication that photosynthesis was occurring within a hard-water lake (Pelechaty et al.,

2013).

4.2.3 Facies C: Lacustrine Carbonaceous Mud

Sediment units of Facies C are clay and silt with increasing organic carbon content up-core. This facies is interpreted as lacustrine deposits with the primary source of organic matter being terrestrial material. Nearly zero MS values and C/N values ~15–

30 record deposition in a stabilized lake catchment (little slumping or debris flow within 56

the lake) with organics matter from the surrounding catchment falling or blowing into the lake and decomposing within the basin (Dearing, 1999; Meyers and Lallier-Verges,

1999).

4.2.4 Facies D: Brecciated Sediment

The brecciated sediment of Facies D contains sediment from Facies A, B, and/or

C in Thompson and Meteer Lake. In both lakes, the brecciated structure is interpreted to record soft sediment deformation events after the deposition of the youngest deformed facies. This deformation is evident in adjacent cores, but in the case of Meteer Lake, is not stratigraphically continuous one meter away. Soft sediment deformation of silt can occur when sediment of a lower density is overlain by one of higher density and deformed in response to instability of the bed (Treese and Wilkinson, 1982). In primarily silt units, this deformation is often a product of varying percentages of sand within the units.

In addition to this deformation, sand and pebbles were observed within primarily massive silt units. These deposits resemble those associated with cohesive debris flows, where dense flows can keep pebbles and sand in suspension within a silt and/or mud matrix (Lowe, 1982). Sediment in these flows could have originated from the walls of the kettle basin during backwasting (Kjær and Krüger, 2001). With the inclusion of clasts characteristic of Facies B and C (of lacustrine origin) in the brecciated facies, the brecciation process must have occurred after the deposition of Facies A–C. According to the pollen samples collected from clasts within Facies D in Thompson Lake, deformation

or cohesive flows must have occurred after 11 ka, the assigned age of the youngest pollen assemblage sampled.

4.2.5 Facies E: Peat

Facies E is a herbaceous peat that with a percentage of organic carbon >50%. This facies is interpreted to have been deposited in a shallow, anoxic lacustrine system where the accumulation of organic matter was greater than the rate of decomposition (Moore,

1987).

4.3 Core Chronology

Chronological data collected from cores (Figure 3.15) are used to interpret maximum and/or minimum ages for ice free conditions within each of the lake basins and other events within the surrounding catchments.

4.3.1 Meteer Lake

The one radiocarbon age from Meteer Lake of 16.2 ± 0.1 cal ka BP within pebbly sand (Facies A) (Figure 3.15) is interpreted as a maximum age for the deposition of this sediment unit, and thus a maximum age for all deposition above this unit. The thawing of ice within the kettle basin and plant succession would have occurred before this time to allow for the transport of terrestrial macrofossils with sand into the thawed kettle basin.

Therefore, this age also is interpreted as a minimum age for the melting of ice within the lake basin and a minimum age for plant succession within the surrounding catchment.

4.3.2 Bullhead Lake

One radiocarbon age and one OSL age from within Facies A of Bullhead Lake are interpreted as maximum ages for the deposition of the lower pebbly sand unit, and deposition of all upper units. An OSL age of 12.7 ± 0.3 (3.3) ka and a radiocarbon age of

13.4 ± 0.05 cal ka BP overlap at 1σ and thus are in agreement with one another. Similar to Meteer Lake, these ages are also interpreted as minimum age for the melting of ice within the lake basin and a minimum age for plant succession within the surrounding catchment.

4.3.3 Hunter Lake

Two radiocarbon ages of 16.0 ± 0.1 cal ka BP and 16.0 ± 0.1 cal ka BP from

Facies A of Hunter Lake overlap with OSL ages of 14.4 ± 0.5 (1.4) ka and 14.8 ± 0.7

(1.5) ka at 1σ. These are considered maximum ages for the deposition of this sediment unit and those sediment units above it. These ages also provide a minimum age for ice free conditions within the basin, and a minimum age for plant succession on the landscape. Pollen ages from Facies C of Hunter Lake are interpreted as maximum ages for a decline in sediment movement within the surrounding catchment, a time where deposition into the lake was dominated by detrital material.

4.3.4 Fish Lake

Chronological data from Fish Lake are in stratigraphic agreement, but do not overlap. A radiocarbon age from the lowest unit of Facies A in this lake of 16.2 ± 0.1 cal ka BP provides a maximum age for the deposition of this lowest unit, and a minimum age 59

for ice free conditions in the basin, as well as a minimum age for plant succession in the surrounding catchment. An OSL age of 9.9 ± 0.3 (2.5) ka dates the deposition of the upper unit of Facies A, and provides a minimum age for the units between this and the lowest unit dated by radiocarbon. Pollen samples from Facies C are consistent with the

OSL age, with sedimentation occurring after 8 ka. This sedimentation indicates a stable surrounding catchment, a time when lacustrine sedimentation was dominated by allochthonous material.

4.3.5 Stone Lake

Two OSL samples from basal sand within Stone Lake’s Facies A record exposure of sand grains to sunlight at 23.2 ± 1.0 (2.2) ka and 23.6 ± 1.1 (2.2) ka. In this same sand a pine needle was radiocarbon dated to 16.0 ± 0.1 cal ka BP. The disagreement between these dating techniques is interpreted to indicate a reworking of previously deposited sediment which did not expose the sediment to sunlight. OSL ages are interpreted to date early deposition in a post-glacial landscape, but the inclusion of younger organics suggests that this sand was then reworked and transported into the kettle basin around 16 ka. These OSL ages are further interpreted as minimum ages for deglaciation along the

Shipshewana Moraine, as sand could not have been bleached in a subglacial environment.

Furthermore, the radiocarbon age is interpreted as a minimum age for Facies A, ice free conditions within the basin, and plant succession on the landscape.

4.3.6 Thompson Lake

Chronological data from Thompson Lake records multiple chronologic reversals

(Figure 3.15). Two OSL ages from the lake’s Facies D, in both the fine and medium sand fractions, record ages of 19.0 ± 0.8 ka and 20.4 ± 2.2 ka. These agreeing ages are above a younger pollen age of 12.0 ka. This reversal is interpreted to be a product of brecciation, as discussed in Section 4.2.4 for Thompson Lake which would have occurred after 10 ka, the age of the youngest dated unit within the brecciated facies. Thus, chronological data in this core record depositional events before the mixing of previously deposited units.

The oldest ages, the two OSL ages, are interpreted to date deposition of sand in a post-glacial environment despite not being in a lower stratigraphic position than the single radiocarbon age due to mixing. However, confidence in these ages is diminished in comparison to other OSL samples due to M/m3 values ≥ 1.05, an indication of poorly bleached sediment (Lepper et al., 2007). The single radiocarbon age, though not is interpreted as a minimum age for ice free conditions within the basin and for plant succession on the landscape.

Chapter 5

Discussion

5.1 Introduction

Extensive collection, analysis, and dating of basal sediment units within lakes along two moraines was conducted to characterize the deposition of these units, and constrain their age. Previous work suggested the slow melting of ice deposited basal trash layers leading to stratified diamicton. However, this work revealed stratified, often well- sorted, sandy sediment facies more consistent with fluvial, aeolian, and/or littoral environments within the basal section of lake basins. Chronologic data taken from these units identifies an apparent melt-out time lag in the region, but its duration can only be estimated by OSL ages from two lakes. These same OSL ages may also provide some evidence for an early retreat of the Saginaw Lobe. In addition, radiocarbon dating may document a regional climate signal, which could account for the abundance of organic material within sediment that has been radiocarbon dated to ~16.0 ka.

5.2 Deposition of Basal Trash Layers

Sediment facies expected by deposition through downwasting in a kettle basin as first described in Florin and Wright (1969) were not observed in lakes cored along the 62

Sturgis and Shipshewana moraines. Though pebbly sand and other sandy sediment is observed in the basal units of lakes, these units do not exhibit sedimentary structures and characteristics associated with such deposition such as: slumping structures and poorly sorted sediment (Eyles, 1979; Kjær and Krüger, 2001). Instead, most lakes contain sorted basal units of massive or faintly laminated, pebbly, coarse-medium sand or sandy silt.

The coarse–medium sand units (referred to as Facies A) are more similar to fluvial flow (James and Dalrymple, 2010); Depositional System C as described in Section

1.8. In some cases this sediment is massive, while in other lakes it is faintly bedded, characteristic of gravity debris deposits. As interpreted, sediment entered the basin through precipitation/melting events or the intersection of the lake by a stream

(Slowinski, 2015). These deposits are located in deep pools within the basins and adjacent to steep slopes, consistent with areas susceptible to debris flows, or where a river would drain to as the lake level rose. However, coarse–medium sand is also consistent with deposition by littoral action, but the lack of cross-bedding and other structures associated with littoral environments suggest that this mode of deposition was either limited or did not play a role in the deposition of these basal sediment units.

The finer sand and silt units observed in Facies A correlate with facies models of low energy debris flows and aeolian transport. Low energy streams, small precipitation events, and/or thawing of the adjacent landscape could have moved this sediment into the lake basins in a similar manner to the modes discussed for coarser sand. In addition, aeolian activity may have mobilized this finer sediment around the basin, and transported it into the lake resulting in grain-fall deposits. Facies A is thus not interpreted to have been deposited through the melting of ice, suggesting the model for basal trash layers 63

originally presented by Florin and Wright (1969) is not applicable. However, it must be acknowledged that what is beneath Facies A could be a trash layer-like unit which would better agree with this model. Refusal during coring prevented sampling below Facies A in all lakes.

5.3 Melt-out Time Lags and Regional Climate Signals

Melt-out Time Lags

In most lakes, the absence of identifiable and datable basal trash layers prevents their basal radiocarbon ages from being associated with any melt-out time lag which may have occurred. Instead radiocarbon ages from Bullhead Lake, Meteer Lake, Fish Lake, and Hunter Lake only provide poorly limiting minimum ages for deglaciation in the region. How poorly they constrain deglaciation is evident as they provided nearly identical minimum ages to the two moraines which mark separate ice marginal positions and cannot be of the same age (Flemming, 1997). It is evident that these minimum ages derived from radiocarbon analysis alone require a maximum age to better constrain deglacial events – which was not achieved through OSL dating in Fish Lake, Bullhead

Lake, Meteer Lake, or Hunter Lake. In these lakes, OSL ages overlap at 1σ, or are younger than basal radiocarbon ages, contributing to the interpretation of sandy sediment being deposited by multiple modes of transport in a paraglacial setting, rather than melt- out of glaciofluvial outwash covering abandoned ice blocks. Thus, these coupled ages constrain a period between plant succession and deposition, but provide no information regarding the melting of buried ice.

OSL ages from basal sand in Thompson Lake and Stone Lake are older than basal radiocarbon ages within the same lakes. In Thompson Lake OSL ages of 19.0 ± 0.8 ka and 20.4 ± 1.4 ka are older than a basal radiocarbon age of 14.8 ± 0.3 cal ka BP.

Similarly, OSL ages from Stone Lake of 23.2 ± 1.0 ka and 23.6 ± 1.1 ka are older than a basal radiocarbon age of 16.0 ± 0.3 cal ka BP. Though not interpreted as glaciofluvial outwash, these sand units and their OSL ages may mark deposition which preceded the melting of ice within the basin – constraining melt-out time lags for the basins at ~5,000 and ~7,000 years. Time lags of this duration are over twice as long as the lag assumed by regional deglacial reconstructions (~2,000 years) by Fullerton (1980) and Dyke (2004).

These new estimated melt-out time lags better compare to those observed in Illinois, where dating of ice-walled lake plains have uncovered melt-out time lags of ~4,000 years

(B. B. Curry personal comm., 2017). Assuming the OSL dated sand was completely bleached before burial, the chronology from Thompson Lake and Stone Lake thus propose melt-out time lags of much greater duration than previously inferred or documented in North America.

Regional Climate Signals

The consistent collection of radiocarbon dates around 16 ka from three studies may suggest a regional influence in the accumulation of organics within sediment associated with the Sturgis and Shipshewana moraines. Radiocarbon ages from this study are similar to ages from bogs and other lakes in the region ~16.0 cal. ka BP (Horton,

2015; Glover et al., 2011). Basal radiocarbon ages from interpreted trash layers also record ages ~16 ka in Illinois (Curry et al., 2008; Curry and Filippelli, 2010), a state which has an abundance of radiocarbon ages of this age (B. B. Curry personal comm., 65

Figure 5.1. Radiocarbon and OSL from the Sturgis and Shipshewana moraines plotted with GRIP temperature data (Alley, 2004) and regional OSL and radiocarbon dates. 66

2017). When plotted with change in global temperature recorded in Greenland Ice Core

Records (Figure 5.1) the 16 ka time frame falls within the middle of the Oldest Dryas, a period (18─14.8 ka) of dry, cold climate (Bradley, 2013). However, these ages also fall within the period known as the “mystery interval” or “big wet” from 17.5-14.5 ka

(Denton et al., 2006). This time period is characterized by contradicting global climatic events, with some regions experiencing rapid cooling and others rapid warming (Denton et al., 2006). In addition, all of these radiocarbon ages post-date Heinrich Event 1 (H-1) at 16.8 ka, an ejection of vast amounts of ice from the Laurentide Ice Sheet into the North

Atlantic as documented by ice-rafted debris deposits in marine sediment (Heinrich,

1988). This event had the potential to slow the northern Atlantic’s thermohaline circulation through the addition of large amounts of fresh water (Hemming, 2004).

Disruption of this current may have reduced the distribution of heat in the northern

Atlantic Ocean and diverted thermal energy to North America (Broecker, 1994). A regional warming may have allowed the proliferation of vegetation around 16.0 ka, which were then preserved in sediment. Pollen records from Crystal Lake in Illinois and Silver

Lake, Ohio both record dense boreal forest around the time of these radiocarbon ages

(Gonzales and Grimm, 2009; Gill et al., 2012). Such a forest could have supplied the landscape with wood fragments, which subsequently were transported into the lake basins.

Two of the five lakes sampled for OSL ages (Thompson Lake and Stone Lake) record deposition of sand before 18.0 ka. These ages are older than OSL ages from other cored lakes and all radiocarbon ages collected in this study. The Stone Lake OSL ages are older than the last glacial maximum (LGM) in Indiana and overlap with ages for LGMs 67

in Illinois and Ohio (Figure 5.1). Ages for these maximum extents between 22─24 ka in

Ohio, Indiana and Illinois are from radiocarbon dating (Lowell et al., 1990; Loope et al.,

2014; Curry et al., 2011). The similarity in ages suggests that OSL ages from Stone and

Thompson Lake not only provide minimum ages for the Sturgis and Shipshewana moraines, but also document an early retreat of the Saginaw Lobe from its unknown maximum position nearly 3,000 years earlier than previously speculated by Fullerton

(1980), Mickelson (1984) and Dyke (2004). Early retreating of ice in positions well north of the LGM has recently been suggested by Schaetzl et al. (2017), where proglacial lake deposits have been documented and dated to ~23 ka with OSL in the northern Lower

Peninsula of Michigan. The basal OSL ages from Thompson and Stone Lake support the original speculations by Schaetzl et al. (2017) and for this study suggest that the Saginaw

Lobe began retreating back into Michigan earlier than its adjacent lobes around the time of the LGM.

Chapter 6

Summary and Conclusions

6.1 Summary

Radiocarbon ages from basal sediment units, frequently referred to as “trash” layers, have long been interpreted to date the earliest deposition within lacustrine basins when abandoned ice blocks melted (i.e. a basin’s earliest age). These ages have also been used to assign minimum ages for regional deglaciation. This study tested the hypothesis that radiocarbon ages from all lakes in the region surrounding the Sturgis Moraine experienced a similar melt-out time lag and basal trash layers within these lakes were deposited in the melt-out manner described by Florin and Wright (1969). Coring and analysis of basal sediment from six lakes along the Sturgis and Shipshewana moraines in southern Michigan and northern Indiana do not provide evidence for this deposition model. Instead, stratigraphy and sedimentological analysis suggest that basal sediment units did not originate above buried ice, but rather originated in the surrounding catchment, having been deposited through some combination of fluvial transport, slumping, aeolian activity, and/or littoral action. Thus, chronological data from these basal units mainly date deposition which occurred after the melting of ice and provide only a minimum age for basin formation with the exception of two basal sand units. 69

These two basal sand units record much earlier subaerial exposure by older OSL ages

(18─24 ka) which may record the earliest deposition in a post-glacial environment along these two moraines and provide the most limiting minimum ages for the moraines thus far. Radiocarbon chronology along both moraines consistently record ages ~16.0 ka which may identify a regional climate signal following climate events related to Heinrich event 1 and the “Big Wet” mystery interval.

6.2 Conclusions

Detailed analysis of basal sediment within kettle lake basins is not consistent with the “drop-down” model proposed by Florin & Wright (1969). Instead, these sediment units resemble sediment deposited by fluvial transport, aeolian activity, littoral action, and/or back wasting. Thus, radiocarbon ages from within these units are not interpreted to date basin formation and are not associated with any melt-out time lag. Younger OSL ages, radiocarbon ages, and pollen records constrain the deposition of allochthonous sediment following the opening of the basin. Only the OSL ages from Thompson Lake and Stone Lake recorded ages older than radiocarbon ages in the region and are interpreted to mark the earliest deposition along each of their associated moraines. Thus, a new minimum age for the Sturgis Moraine of 20.4 ± 1.4 ka is proposed, with radiocarbon ages suggesting a melt-out time lag within the lake of ~ 5 ka. From Stone

Lake, an OSL age provides a minimum age of 23.6 ± 1.1 ka for the Shipshewana

Moraine, with a melt-out time lag of ~7 ka.

6.3 Implications

This study presented chronological data with three different methods from six different lakes and found that basal radiocarbon ages alone do not provide limiting ages for deglaciation in this region formally glaciated by the Laurentide Ice Sheet. However, these radiocarbon ages do have significance, as they correlate with many other ages in region and may record a regional climate influence on the abundance of organic material dated to ~16 ka. In two of the lakes, OSL ages record subaerial exposure of basal sediment before 18 ka. These OSL ages paired with basal radiocarbon ages provide limiting ages for melt-out time lags and potentially provide more limiting age for deglaciation of the Saginaw Lobe, but the accuracy of such OSL ages in poorly bleaching environments requires additional samples to be collected. However, assuming the OSL ages from Stone and Thompson Lake record the complete bleaching of sand, this study has provided some of the first direct evidence for a retreat of the Saginaw Lobe into southern Michigan around the time of the LGM. With the results of this study and Horton

(2015), the Sturgis Moraine is now the most thoroughly dated moraine of the Saginaw

Lobe, and one of the more extensively dated regions in the Midwest for last retreat of the

Laurentide Ice Sheet (Figure 6.1).

6.4 Future Work

Future work into the origin of melt-out time lags and their extent should focus on fewer lakes, and core these lakes more extensively. This method would allow for a greater investigation into the extent and characteristics of basal lake sediment. In

addition, more powerful coring techniques should be pursued to ensure that the base of lake sediment is being achieved.

Studies aiming to better understand the chronology of the Saginaw Lobe’s retreat should look to date other geomorphic events in the region, such as the Kankakee flood or the Imlay outlet. Such events are critical to current reconstructions of the lobes retreat, but are not well constrained.

Figure 6.1. A nearly complete list of published radiocarbon ages by region in the

Midwest United States from Dyke (2004) updated with ages from Glover et al.

(2011), Horton (2015) and this study. Map is thoroughly complete in the tristate region of Ohio, Indiana, and Michigan where this study was conducted.

References

Aitken, M. J., 1998, An Introduction to optical dating: The dating of Quaternary

sediments by the use of photon-stimulated luminescence., New York, Oxford

University Press, 280 p.

Allen, J. R. L., 1984, Sedimentary Structures: Their Character and Physical Basis,

Amsterdam, The Netherlands, Elsevier, Developments in Sedimentology.

Alley, R. B., 2004, The Younger Dryas cold interval as viewed from central Greenland:

Quaternary Science Reviews, v. 19, p. 213-226.

Almquist-Jacobson, H., Almendinger, J. E., and Hobbie, S., 1992, Influence of Terrestrial

Vegetation on Sediment-Forming Processes in Kettle Lakes of West-Central

Minnesota: Quaternary Research, v. 38, p. 103-116.

Ballantyne, C. K., 2002, Paraglacial geomorphology: Quaternary Science Reviews, v. 21,

p. 1935-2017.

Barnett, P. J., 1979, Glacial Lake Whittlesey: the probable ice frontal position in the

eastern end of the Lake Erie basin: Canadian Journal of Earth Science, v. 16, p.

568-574.

Birks, H. J. B., 1980, The Present Flora and Vegetation of the Moraines of the Klutlan

Glacier, Yukon Territory, Canada: A Study in Plant Succession: Quaternary

Research, v. 14, p. 60-86.

Blaszkiewicz, M., 2011, Timing of the final disappearance of permafrost in the central

European Lowland, as reconstructed form the evolution of lakes in N Poland:

Geological Quarterly, v. 55, no. 4, p. 361-374.

Blewett, W. L., Winters, H. A., and Rieck, R. L., 1993, New age control on the Port

Huron Moraine in Northern Michigan: Physical Geography, v. 14, no. 2, p. 131-

138.

Bradley, R. S., 2015, Paleoclimatology: Reconstructing climate of the Quaternary,

Oxford, UK, Elsevier.

Broecker, W., 1994, Massive iceberg discharges as triggers for global climate change:

Nature, v. 372, no. 1, p. 421-424.

Burgis, W. A., 1970, The Imlay outlet of glacial lake Maumee, Imlay City, Michigan.

(Master’s thesis). University of Michigan.

Campbell, M. C., Fisher, T. G., and Goble, R. J., 2017, Terrestrial sensitivity to abrupt

cooling recorded by aeolian activity in northwest Ohio, USA: Quaternary

Research, v. 75, no. 03, p. 411-416.

Curry, B. B., Grimm, E. C., Slate, J. E., Hansen, B. C. S., and Konen, M. E., 2008, The

Late-Glacial and Early Holocene Geology, Paleoecology, and Paleohydrology of

the Brewster Creek Site, a Proposed Wetland Restoration Site, Pratt’s Wayne

Woods Forest Preserve, and James “Pate” Philip State Park, Bartlett, Illinois:

Illinois State Geological Survey Circular, v. 571, p. 44.

Curry, B. B., and Filippelli, G. M., 2010, Episodes of low dissolved oxygen indicated by

ostracods and sediment geochemistry at Crystal Lake, Illinois, USA: Limnology

and Oceanography, v. 55, no. 6, p. 2403-2423. 74

Curry, B. B., Hajic, E. R., Clark, J. A., Befus, K. M., Carrell, J. E., and Brown, S. E.,

2014, The Kankakee Torrent and other large meltwater flooding events during the

last deglaciation, Illinois, USA: Quaternary Science Reviews, v. 90, p. 22 - 36.

Curry, B. B., and Petras, J., 2011, Chronological framework for the deglaciation of the

Lake Michigan lobe of the Laurentide Ice Sheet from ice-walled lake deposits:

Journal of Quaternary Science, v. 26, no. 4, p. 402 - 410.

Cyr, H., 1998, Effects of wave disturbance and substrate slope on sediment

characteristics in the littoral zone of small lakes: Can. J. Fish. Aquat. Sci., v. 55,

p. 967-976.

Dearing, J., 1999, Magnetic susceptibility, Environmental magnetism: a practical guide:

Quaternary Research Association London, v. 6, p. 35-62.

Denton, G., Broecker, W., and Alley, R., 2006, The mystery interval 17.5 to 14.5 kyrs

ago: News, v. 14, no. 2, p. 14-16.

Derouin, S. A., Lowell, T. V., and Hajdas, I., 2007, Landscape Evolution and

Deglaciation of the Upper Peninsula, Michigan: An Examination of Chronology

and Stratigraphy in Kettle Lake Cores: Journal of Great Lakes Research, v. 33,

no. 4, p. 875-886.

DeVries-Zimmerman, S., Fisher, T. G., Hansen, E. C., Dean, S., and Björck, S., 2014,

Sand in lakes and bogs in Allegan County, Michigan, as a proxy for eolian sand

transport: Geological Society of America, Special Papers, 508, p.111-131.

Dyke, A. S., 2004, An outline of North American deglaciation with emphasis on central

and northern Canada: Quaternary glaciations: Extent and chronology, v. 2, p. 373

424. 75

Eschman, D. F., and Karrow, P. F., 1985, Quaternary Evolution of the Great Lakes:

Geological Association of Canada Special Paper, v. 30, p. 79 - 93.

Ekblaw, G. E., and Athy, L. F., 1925, Glacial Kankakee torrent in northeastern Illinois:

Bulletin of the Geologic Society of America, v. 36, p. 417 - 428.

Eyles, N., 1979, Facies of supraglacial sedimentation on Icelandic and Alpine temperate

glaciers: Canadian Journal of Earth Science, v. 16, p. 1341-1361.

Fisher, T. G., and Taylor, L. D., 2002, Sedimentary and stratigraphic evidence for

subglacial flooding, south-central Michigan, USA: Quaternary International, v.

90, p. 87 - 115.

Fisher, T. G., Jol, H. M., and Boudreau, A. M., 2005, Saginaw Lobe tunnel channels

(Laurentide Ice Sheet) and their significance in south-central Michigan, USA:

Quaternary Science Reviews, v. 24, p. 2735 - 2391.

Fisher, T. G., Blockland, J. D., Anderson, B., Krantz, D. E., Stierman, D. J., and Goble,

R., 2015, Evidence of Sequence and Age of Ancestral Lake Erie Lake-Levels,

Northwest Ohio: Ohio Journal of Science, v. 115, no. 2, p. 61 - 77.

Fleming, A.H., Brown, S.E., Smous, A.J., and Schrader, T.L., 1997, Glacial terrains of

the Topeka, Shipshewana, Oliver Lake, Lagrange, and Sturgis Quadrangles,

Noble and Lagrange Counties, Indiana: Indiana Geological Survey Open-File

Report 97-3, scale 1:24,000.

Florin, M. B., and Wright, H. E., 1969, Diatom evidence for the persistence of stagnant

glacial ice in Minnesota: Geological Society of America Bulletin, v. 80, p. 695

704.

Fullerton, D. S., 1980, Preliminary Correlation of Post-Erie Interstadial Events (16,000 –

10,000 Radiocarbon Years Before Present), Central and Eastern Great Lakes

Region, and Hudson, Champlain, and St. Lawrence Lowlands, United States and

Canada: Geological Survey Professional paper, v. 1089.

Gill, J. L., Williams, J. W., Jackson, S. T., Lininger, K. B., and Robinson, G. S., 2009,

Pleistocene megafaunal collapse, novel plant communities and enhanced fire

regimes in North America: Science, v. 326, p. 1100-1103.

Gill, J. L., Williams, J. W., Jackson, S. T., Donnelly, J. P., and Schellinger, G. C., 2012,

Climatic and megaherbivory controls on late-glacial vegetation dynamics: a new,

high-resolution, multi-proxy record from Silver Lake, Ohio: Quaternary Science

Reviews, v. 34, p. 66-80.

Glover, K. C., Lowell, T. V., Wiles, G. C., Pair, D., Applegate, P., and Hajdas, I., 2011,

Deglaciation, basin formation and post-glacial climate change from network of

sediment core sites in Ohio and eastern Indiana: Quaternary Research, v. 76, p.

401 - 410.

Gonzales, L. M., and Grimm, E. C., 2009, Synchronization of late-glacial vegetation

changes at Crystal Lake, Illinois, USA with the North Atlantic Event

Stratigraphy: Quaternary Research, v. 72, no. 02, p. 234-245.

Gravenor, C. P., and Stupavsky, M., 1976, Magnetic, physical and lithologic properties

and age of till exposed along the east coast of Lake Huron, Ontario: Canadian

Journal of Earth Science, v. 13, no. 12, p. 1655-1666.

Grimm, E. C., Maher, L. J., and Nelson, D. M., 2009, The magnitude of error in

conventional bulk-sediment radiocarbon dates from central North America:

Quaternary Research, v. 72, no. 2, p. 301-308.

Hanes, B. E., Fisher, T. G., Becker, R. H., and Martin-Hayden, J. M., 2014, Elucidating

paleo dune activity and timing from wetlands in the lee of coastal sand dunes,

Grand Mere Lakes, Michigan, USA: Geological Society of America, Special

Papers, 508, p. 133-141.

Hassan, K. M., Swinehart, J. B., and Spalding, R. F., 1997, Evidence for Holocene

environmental change from C/N ratios, and 13C and 15N values in Swan Lake

sediments, western Sand Hills, Nebraska: Journal of Paleolimnology, v. 18, p.

121-130.

Heinrich, H., 1988, Origin and Consequences of Cyclic Ice Rafting in the Northeast

Atlantic Ocean during the Past 130,000 Years: Quaternary Research, v. 29, p.

142-152.

Heiri, O., Lotter, A. F., and Lemcke, G., 2001, Loss on ignition as a method for

estimating organic and carbonate content in sediments, reproducibility and

comparability of results: Journal of Paleolimnology, v. 25, p. 101-110.

Hemming, S. R., 2004, Heinrich events: Massive late Pleistocene detritus layers of the

North Atlantic and their global climate imprint: Reviews of Geophysics, v. 42, no.

Higley, M.C., Fisher, T.G., Jol, H.M., Lepper, K., Martin-Hayden, J.M., 2014,

Stratigraphic and chronologic analysis of the Warren Beach, northwest Ohio,

USA. Canadian Journal of Earth Science. 51:737–749. 78

Horton, J. M., 2015, The Deglacial Chronology of the Sturgis Moraine in South-Central

Michigan and Northeast Indiana. (Master’s thesis). University of Toledo.

Retrieved from OhioLINK Electronic Theses and Dissertations Center.

Howard, J. L., 2010, Late Pleistocene glaciolacustrine sedimentation and paleogeography

of southeastern Michigan, USA: Sedimentary Geology, v. 223, no. 1-2, p. 126-

142.

Hunter, R. E., 1977, Basic types of stratification in small eolian dunes: Sedimentology, v.

24, p. 361-387.

James, N. P., and Dalrymple, R. W., 2010, Facies Models 4, Canada, Geological

Association of Canada, GEOtext, v. 6.

Kehew, A. E., Esch, J. M., Kozlowski, A. L., and Ewald, S. K., 2012, Glacial

landsystems and dynamics of the Saginaw Lobe of the Laurentide ice sheet,

Michigan, USA: Quaternary International, v. 260, p. 21-31.

Kehew, A. E., Ewald, S. K., Esch, J. M., and Kozlowski, A. L., 2013, On the origin of

tunnel valleys of the Saginaw Lobe of the Laurentide ice sheet; Michigan, USA:

Boreas, v. 42, no. 2, p. 442-462.

Kempf, P., Moernaut, J., Van Daele, M., Vermassen, F., Vandoorne, W., Pino, M.,

Urrutía, R., Schmidt, S., Garrett, E., and De Batist, M., 2015, The sedimentary

record of the 1960 tsunami in two coastal lakes on Isla de Chiloé, south central

Chile: Sedimentary Geology, v. 328, p. 73-86.

Kempf, P., Moernaut, J., Van Daele, M., Vandoorne, W., Pino, M., Urrutia, R., and De

Batist, M., 2017, Coastal lake sediments reveal 5500 years of tsunami history in

south central Chile: Quaternary Science Reviews, v. 161, p. 99-116. 79

Kjær, K. H., and Krüger, J., 2001, The final phase of dead-ice moraine development:

process and sediment architecture, Kötlujökull, Iceland: Sedimentology, v. 48, p.

935-952.

Kozlowski, A. L., Kehew, A. E., and Bird, B. C., 2005, Outburst flood origin of the

Central Kalamazoo River Valley, Michigan, USA: Quaternary Science Reviews,

v. 24, no. 22, p. 2354-2374.

Krüger, J., and Kjær, K. H., 2000, De-icing progression of ice-cored moraines in a

humid, subpolar climate, Kötlujökull, Iceland: The Holocene, v. 10, no. 6, p. 737-

747.

Lagerbäck, R., and Roberstsson, A., 1988, Kettle holes — stratigraphical archives for

Weichselian geology and palaeoenvironment in northmost Sweden: Boreas, v. 17,

p. 439-468.

Larson, G., and Schaetzl, R., 2001, Review: Origin and Evolution of the Great Lakes:

Journal of Great Lakes Research, v. 27(4), p. 518 - 546.

Lepper, K., Fisher, T. G., Hajdas, I., and Lowell, T. V., 2007, Ages for the Big Stone

Moraine and the oldest beaches of glacial Lake Agassiz: Implications for

deglaciation chronology: Geology, v. 35, no. 7, p. 667-670.

Leverett, F., and Taylor, F. B., 1915, The Pleistocene of Indiana and Michigan and the

history of the Great Lakes, USA, US Government Printing Office.

Linick, T. W., Damon, P. E., Donahue, D. J., and Jull, A. J. T., 1989, Accelerator mass

spectrometry: The new revolution in radiocarbon dating: Quaternary

International, v. 1, p. 1-6.

Loope, H. M., Lowell, T. V., and Curry, B. B., Chronology of Laurentide Ice Sheet (East

White Sublobe) Advance to its Maximum Wisconsin Limit, Southeastern Indiana,

USA, in Proceedings Geological Society of America Annual Meeting, Vancouver,

British Columbia, Oct. 20 2014.

Lowe, D. R., 1982, Sediment Gravity Flows: II. Depositional Models with Special

Reference to the Deposits of High-density Turbidity Currents: Journal of

Sedimentary Petrology, v. 52, no. 1, p. 279-297.

Lowell, T. V., and Savage, K. M., 1990, Radiocarbon Analyses from Cincinnati, Ohio,

and their Implications for Glacial Stratigraphic Interpretations: Quaternary

Research, v. 34, p. 1-11.

McAndrews, J.H., Berti, A.A. and Norris, G. 1973. Key to the Quaternary Pollen and

Spores of the Great Lakes Region. Royal Ontario Museum Publications in Life

Sciences.

Meyers, P. A., and Ishwatari, R., 1993, Lacustrine organic geochemistry - an overview of

indicators of organic matter sources and diagenesis in lake sediments: Organic

Geochemistry, v. 20, no. 7, p. 867-900.

Meyers, P. A., and Lallier-Verges, E., 1999, Lacustrine sedimentary organic matter

records of Late Quaternary paleoclimates: Journal of Paleolimnology, v. 21, p.

345-372.

Miall, A. D., 1978, Lithofacies types and vertical profile models in braided river deposits:

a summary: Canadian Society of Petroleum Geologists Memoir, v. 5, p. 597-604.

Mickelson, D.M., Clayton, L., Fullerton, D.S., Borns, H.W., 1983. The Late Wisconsin

glacial record of the Laurentide Ice Sheet in the United States. In: Wright Jr., H.E.

(Ed.), Late Quaternary Environments of the United States The Late Pleistocene

vol. 1. Univ. Minn. Press, Minneapolis, pp. 3–37.

Moore, P. D., 1987, Ecological and hydrological aspects of peat formation, Geological

Society of London, Special Publications, v. 32.

Myrow, P. M., and Hiscott, R. N., 1991, Shallow-water gravity-flow deposits, Chapel

Island Formation, southeast Newfoundland, Canada: Sedimentology, v. 38, p.

935-959.

Pelechaty, M., Pukacz, A., Apolinarska, K., Pelechata, A., and Siepak, M., 2013, The

significance of Chara vegetation in the precipitation of lacustrine calcium

carbonate: Sedimentology, v. 60, p. 1017-1035.

Sasaki, H., Sasaki, Y., Saito-Kato, M., Naruse, H., Yumi, M., and Ishihara, Y., 2016,

Stratigraphic variations in lacustrine sediment gravity-flow deposits intercalated

in varved diatomite: An example from the Hiruzenbara Formation, Okayama

Prefecture, southwest Japan: Quaternary International, v. 397, p. 208-222.

Stafford, T. W., Jull, A. J. T., Brendel, K., Duhamel, R., and Donahue, D., 1987, Study of

bone radiocarbon dating accuracy at the University of Arizona NSF Accelerator

Facility for Radioisotope Analysis: Radiocarbon, v. 29, no. 1, p. 24-44.

Schaetzl, R. J., Lepper, K., Thomas, S. E., Grove, L., Treiber, E., Farmer, A., Fillmore,

A., Lee, J., Dickerson, B., and Alme, K., 2017, Kame deltas provide evidence for

a new glacial lake and suggest early glacial retreat from central Lower Michigan,

USA: Geomorphology, v. 280, p. 167-178. 82

Schnurrenberger, D., Russell, J., and Kelts, K., 2003, Classification of lacustrine

sediments based on sedimentary components: Journal of Paleolimnology, v. 29,

no. 2, p. 141 - 154.

Schomacker, A., 2008, What controls dead-ice melting under different climate

conditions? A discussion: Earth Science Reviews, v. 90, p. 103-113.

Slowinski, M., Blaszkiewicz, M., Brauer, A., Noryśkiewicz, B., Ott, F., and Tyszkowski,

S., 2015, The role of melting dead ice on landscape transformation in the early

Holocene in Tuchola Pinewoods, North Poland: Quaternary International, v. 388,

p. 64-75.

Thompson, T. A., 1989, Anatomy of a Transgression along the Southeastern Shore of

Lake Michigan: Journal Of Coastal Research, v. 5, no. 4, p. 711-724.

Treese, K. L., and Wilkinson, B. H., 1982, Peat-marl deposition in a Holocene paludal

lacustrine basin—Sucker Lake, Michigan: Sedimentology, v. 29, p. 375-390.

Walker, R. G., 1986, Facies Models, Toronto, Ontario, Geological Association of

Canada.

Wright, H. E., 1991, Coring tips: Journal of Paleolimnology, v. 6, p. 37-49.

Appendix A

Core Data Summary

UTM Z16 UTM Z16 Starting Thrust Date Lake N E Core Section ID Depth Length 5/19/2016 Fish 4636881 625943 1A-1T 11.5 1 1A-2T 12.5 1 1B-1T 12.5 1

5/19/2016 Bullhead 4639884 621700 1A-1T 4 1 1A-2T 5 1 1B-1T 5 1 1C-1T 5 1

5/20/2016 Thompson 4631603 625133 1A-1T 10 1 1A-2T 11 1 1A-3T 12 1 1A-4T 13 1 1A-5T 14 1 1A-6T 15 1 1A-7T 16 1 1A-8T 17 1 1B-1T 15.5 1 1B-2T 16.5 1 1B-3T 17.5 1 1C-4T 17.5 1

5/26/2016 Hunter 4619762 610750 1A-1T 12 1 1A-2T 13 1 1A-3T 14 0.75 1B-1T 13.5 1 1B-1T 14.5 0.5 1C-1T 14 0.75

5/26/2016 Stone 4622191 611831 1A-1T 11 1 1A-2T 12 1 1A-3T 13 0.75 1B-1T 10.5 1 1B-2T 11.5 1 1B-3T 12.45 1 1C-1T 13 1

7/8/2015 Meter 4619906 635333 1A-1T 7.5 1

1A-2T 8.5 1 1A-3T 9.5 1 1A-4T 10.5 1 1A-5T 11.5 1 1B-1T 9 1 1B-2T 10 1 1B-3T 11 0.55

Appendix B

Loss-on-ignition

THOMPSON-1B-3T 550°C 1000°C wet wt 100*C wt wt 550° LOI 1000° LOI residue Depth in cruc. smpl& Dry smpl& smpl& Core ID % % Wt (g) Wt (g) cruc (g) wt (g) cruc (g) cruc (g) section (cm)

89 56 5.2539 6.7001 6.5158 6.5056 6.4013 0.81 8.27 1.1474

87 60 5.4623 6.3105 6.2159 6.2088 6.1276 0.94 10.77 0.6653

85 78 4.4836 5.6438 5.505 5.4934 5.3955 1.14 9.58 0.9119

83 86 4.5084 5.7477 5.5696 5.5565 5.4785 1.23 7.35 0.9701

81 83 5.6724 6.5217 6.3999 6.3883 6.3339 1.59 7.48 0.6615

79 85 5.5609 6.5965 6.466 6.4556 6.3729 1.15 9.14 0.812

77 44 5.3853 6.4589 6.3268 6.3189 6.237 0.84 8.70 0.8517

75 102 5.6124 6.7208 6.5659 6.5591 6.4988 0.71 6.32 0.8864

73 101 4.5771 6.1968 5.9642 5.9533 5.8419 0.79 8.03 1.2648

71 19 5.0621 5.967 5.6672 5.6541 5.3972 2.16 42.46 0.3351

69 57 5.2484 6.0542 5.7831 5.7728 5.5468 1.93 42.27 0.2984

67 37 5.3583 6.2814 5.9634 5.9511 5.6932 2.03 42.62 0.3349

65 77 4.8335 5.6676 5.3889 5.3774 5.1418 2.07 42.42 0.3083

63 79 5.5521 6.3851 6.1035 6.0918 5.8599 2.12 42.06 0.3078

61 65 4.8176 5.5593 5.3105 5.2999 5.0919 2.15 42.20 0.2743

59 68 5.7744 7.0614 6.8329 6.8213 6.6731 1.10 14.00 0.8987

57 58 5.3435 6.5974 6.429 6.4194 6.3089 0.88 10.18 0.9654

55 7 4.4685 5.5749 5.3741 5.3639 5.2527 1.13 12.28 0.7842

53 13 5.7344 6.6291 6.3305 6.3167 6.0677 2.32 41.77 0.3333

51 35 4.6788 5.6842 5.3568 5.3419 5.0798 2.20 38.66 0.401

49 52 4.6766 5.8312 5.475 5.4569 5.1857 2.27 33.97 0.5091

47 72 5.4645 6.2627 6.0039 5.9925 5.7658 2.11 42.03 0.3013

45 12 5.4252 6.1488 5.9077 5.8967 5.6952 2.28 41.76 0.27

43 98 5.0296 5.9476 5.6207 5.6058 5.3599 2.52 41.60 0.3303

41 69 5.7109 6.4366 6.1772 6.1668 5.9715 2.23 41.88 0.2606

39 97 5.5344 6.4999 6.164 6.1501 5.8906 2.21 41.22 0.3562

37 80 5.4049 6.4577 6.1734 6.161 5.9015 1.61 33.77 0.4966

35 75 4.9099 5.9773 5.7076 5.6954 5.4746 1.53 27.68 0.5647

33 74 6.1398 7.0239 6.8295 6.8197 6.6175 1.42 29.32 0.4777

31 46 5.5746 6.4802 6.1917 6.1801 5.9338 1.88 39.91 0.3592

29 2 4.9217 5.8244 5.5755 5.5638 5.3379 1.79 34.55 0.4162

27 71 4.4419 5.4383 5.2062 5.1923 5.0068 1.82 24.27 0.5649

25 54 4.9632 6.1782 5.8678 5.8509 5.5949 1.87 28.30 0.6317

23 94 5.564 6.83 6.448 6.4217 6.0902 2.98 37.50 0.5262

21 95 5.8142 6.703 6.438 6.419 6.1826 3.05 37.90 0.3684

19 84 4.905 5.9321 5.6312 5.6105 5.3318 2.85 38.38 0.4268

17 81 4.9088 5.7942 5.5217 5.5085 5.2563 2.15 41.15 0.3475

15 26 4.9657 6.0187 5.793 5.779 5.5821 1.69 23.80 0.6164

13 3 4.7696 5.7447 5.6026 5.5926 5.4614 1.20 15.75 0.6918

11 62 5.3029 6.4936 6.2139 6.1976 5.96 1.79 26.08 0.6571

9 15 5.0906 6.1363 5.8523 5.8375 5.5913 1.94 32.32 0.5007

7 43 5.3865 6.3811 6.1773 6.1651 5.9677 1.54 24.96 0.5812

5 91 4.4913 5.6593 5.3083 5.2893 4.9445 2.33 42.20 0.4532

3 64 5.1816 6.3225 5.9813 5.9631 5.6261 2.28 42.14 0.4445

1 49 4.6618 5.8725 5.5121 5.4922 5.1336 2.34 42.17 0.4718

STONE-1A-3T 550°C 1000°C wet wt 100*C wt wt 550° LOI 1000°C residue Depth in cruc. smpl& Dry smpl& smpl& Core ID % % Wt (g) Wt (g) cruc (g) wt (g) cruc (g) cruc (g) section (cm)

73 2 4.9224 7.7982 7.1116 7.0795 6.711 1.47 16.83 1.7886

71 18 5.6044 7.5989 7.163 7.1425 6.8989 1.32 15.63 1.2945

69 63 5.0822 7.8359 7.3857 7.3743 7.2513 0.49 5.34 2.1691

67 75 4.9102 7.8814 7.394 7.3746 7.164 0.78 8.48 2.2538

65 22 5.4039 8.0098 7.5675 7.5488 7.3662 0.86 8.44 1.9623

63 70 5.5002 8.0236 7.3346 7.3004 6.89 1.86 22.37 1.3898

61 12 5.4253 7.2852 6.9015 6.888 6.714 0.91 11.79 1.2887

59 46 5.5749 8.3055 7.6179 7.588 7.2362 1.46 17.22 1.6613

57 79 5.526 7.7022 6.9039 6.8707 6.4405 2.41 31.22 0.9145

55 71 4.4422 7.0946 6.3336 6.3059 5.9896 1.46 16.72 1.5474

53 66 5.5654 7.7853 6.9438 6.9171 6.5749 1.94 24.83 1.0095

51 89 4.6566 6.9802 6.1797 6.1391 5.7736 2.67 24.00 1.117

49 22 5.4036 7.0258 6.4766 6.4462 6.1804 2.83 24.77 0.7768

47 51 5.1367 5.9758 5.7039 5.6884 5.554 2.73 23.70 0.4173

45 63 5.082 6.2108 5.9207 5.9022 5.7357 2.21 19.85 0.6537

43 66 5.5653 6.56 6.4145 6.4077 6.349 0.80 6.91 0.7837

41 48 5.3548 6.2558 6.0477 6.0352 5.9203 1.80 16.58 0.5655

39 1 5.7032 6.7792 6.5157 6.5004 6.3615 1.88 17.10 0.6583

37 92 5.3952 6.368 6.1543 6.1389 6.0265 2.03 14.81 0.6313

35 50 4.7992 5.7512 5.5193 5.5019 5.3787 2.42 17.11 0.5795

33 93 5.5982 6.3782 6.1148 6.0951 5.9637 3.81 25.44 0.3655

31 18 5.604 6.5965 6.2752 6.2531 6.0893 3.29 24.40 0.4853 89

29 82 5.737 6.5045 6.28 6.2632 6.1475 3.09 21.31 0.4105

27 70 5.4998 6.4018 6.19 6.1737 6.0605 2.36 16.40 0.5607

25 59 4.9722 5.7207 5.5651 5.553 5.463 2.04 15.18 0.4908

23 67 5.1225 6.0525 5.8026 5.784 5.6446 2.73 20.50 0.5221

21 23 5.617 6.3685 6.1961 6.1822 6.0731 2.40 18.84 0.4561

19 89 4.6566 5.3772 5.2003 5.1836 5.0743 3.07 20.10 0.4177

FISH-1A-2T 550°C 1000°C wet wt 100*C wt wt 550° LOI 1000°C residue Depth in cruc. smpl& Dry smpl& smpl& Core ID % % Wt (g) Wt (g) cruc (g) wt (g) cruc (g) cruc (g) section (cm)

91 94 5.5645 6.5888 6.4651 6.4513 6.4181 1.53 3.69 0.8536

89 54 4.9634 6.1451 5.9511 5.9305 5.8585 2.09 7.29 0.8951

87 64 5.1819 6.293 5.9994 5.9703 5.7852 3.56 22.64 0.6033

85 68 5.7741 6.5017 6.378 6.3544 6.2489 3.91 17.47 0.4748

83 13 5.7345 6.4983 6.2812 6.2621 6.1088 3.49 28.04 0.3743

81 102 5.6125 6.6802 6.408 6.3856 6.2724 2.82 14.23 0.6599

79 71 4.4423 5.3827 5.1669 5.1494 5.0867 2.42 8.65 0.6444

77 3 4.7699 5.9591 5.7504 5.7352 5.6845 1.55 5.17 0.9146

75 79 5.5525 6.6703 6.5066 6.5002 6.4768 0.67 2.45 0.9243

73 57 5.2487 6.2608 6.1459 6.1396 6.0923 0.70 5.27 0.8436

71 37 5.3585 6.0166 5.9415 5.938 5.9185 0.60 3.34 0.56

69 95 5.8147 6.6326 6.5043 6.4984 6.4671 0.86 4.54 0.6524

67 85 5.5308 6.693 6.4901 6.4838 6.4471 0.66 3.83 0.9163

65 35 4.6792 6.0576 5.7699 5.7595 5.7185 0.95 3.76 1.0393

63 46 5.575 6.6406 6.4299 6.4133 6.3219 1.94 10.69 0.7469

61 49 4.6621 5.5632 5.3875 5.372 5.2973 2.14 10.30 0.6352

59 2 4.9221 5.5616 5.4577 5.451 5.3939 1.25 10.66 0.4718

57 43 5.3868 6.2628 6.0997 6.0915 6.0067 1.15 11.90 0.6199

55 77 4.8336 6.1056 5.8499 5.8318 5.707 1.78 12.28 0.8734

53 19 5.0622 5.8512 5.4667 5.4401 5.4131 6.58 6.67 0.3509

51 86 4.5082 5.0821 4.6994 4.6709 4.6626 14.91 4.34 0.1544

49 44 5.3854 5.9817 5.5641 5.5339 5.5277 16.90 3.47 0.1423

47 74 6.14 6.9321 6.3901 6.3515 6.344 15.43 3.00 0.204

45 91 4.4915 5.1789 4.6715 4.6351 4.6301 20.22 2.78 0.1386

43 84 4.9051 5.511 5.0662 5.0337 5.0295 20.17 2.61 0.1244

41 72 5.4648 6.0137 5.602 5.5715 5.5682 22.23 2.41 0.1034

39 75 4.9105 5.4572 5.0484 5.0171 5.0129 22.70 3.05 0.1024 90

37 98 5.03 5.6475 5.1504 5.1144 5.1108 29.90 2.99 0.0808

35 80 5.4055 6.2285 5.548 5.4987 5.4939 34.60 3.37 0.0884

33 26 4.9662 5.6326 5.1036 5.065 5.0611 28.09 2.84 0.0949

31 58 5.3433 5.9357 5.4661 5.4322 5.4287 27.61 2.85 0.0854

29 60 5.4625 6.0712 5.575 5.5398 5.5364 31.29 3.02 0.0739

27 15 5.0909 5.6689 5.2014 5.1672 5.1642 30.95 2.71 0.0733

25 78 4.4834 4.9994 4.5931 4.563 4.5601 27.44 2.64 0.0767

23 101 4.5772 5.1278 4.7016 4.6713 4.6678 24.36 2.81 0.0906

21 73 4.4684 5.0925 4.6025 4.5676 4.5634 26.03 3.13 0.095

19 81 4.9088 5.4644 5.0245 4.9937 4.9897 26.62 3.46 0.0809

17 56 5.2538 5.9176 5.3695 5.331 5.3271 33.28 3.37 0.0733

15 12 5.4252 6.0418 5.545 5.5095 5.5063 29.63 2.67 0.0811

13 69 5.7111 6.2421 5.8197 5.7898 5.7871 27.53 2.49 0.076

11 65 4.8176 5.518 4.9636 4.9249 4.921 26.51 2.67 0.1034

9 83 5.6722 6.2149 5.7854 5.7562 5.7532 25.80 2.65 0.081

7 62 5.3028 6.0522 5.514 5.4775 5.463 17.28 6.87 0.1602

5 52 4.6775 5.2969 4.8563 4.8251 4.8137 17.45 6.38 0.1362

3 97 5.5347 6.4363 6.1411 6.1215 6.0534 3.23 11.23 0.5187

1 BLK 3.9924 4.7747 4.1623 4.1264 4.1207 21.13 3.35 0.1283

BULLHEAD-1B-1T 550°C 1000°C

wet wt 100*C wt wt 550° LOI 1000°C residue Depth in cruc. smpl& Dry smpl& smpl& Core ID % % Wt (g) Wt (g) cruc (g) wt (g) cruc (g) cruc (g) section (cm)

82 91 4.4916 6.8154 6.3803 6.3202 6.3067 3.18 0.71 1.8151

80 13 5.735 8.7014 8.2259 8.176 8.1616 2.00 0.58 2.4266

78 78 4.4835 7.7994 7.323 7.3098 7.3036 0.46 0.22 2.8201

76 85 5.5613 8.1703 7.8385 7.8248 7.8191 0.60 0.25 2.2578

74 44 5.3854 7.1027 6.8354 6.8019 6.7935 2.31 0.58 1.4081

72 3 4.77 6.7914 6.4484 6.4003 6.3878 2.87 0.74 1.6178

70 94 5.644 8.3708 7.9805 7.9686 7.9631 0.51 0.24 2.3191

68 68 5.7743 7.9863 7.6549 7.6315 7.6247 1.24 0.36 1.8504

66 65 4.8179 6.4795 6.2312 6.2046 6.1966 1.88 0.57 1.3787

64 52 4.6769 8.0539 7.5377 7.4949 7.4804 1.50 0.51 2.8035

62 101 4.577 6.5779 6.2959 6.2797 6.2734 0.94 0.37 1.6964

60 102 5.6125 8.1844 7.7095 7.6505 7.6344 2.81 0.77 2.0219

58 18 5.6048 6.805 6.6007 6.5656 6.5579 3.52 0.77 0.9531

56 67 5.1226 6.208 6.0536 6.0247 6.0177 3.10 0.75 0.8951 91

54 71 4.4428 5.4307 5.3076 5.2842 5.2789 2.71 0.61 0.8361

52 51 5.1372 6.3565 6.1095 6.0635 6.055 4.73 0.87 0.9178

50 85 5.5611 6.4077 6.1793 6.133 6.1243 7.49 1.41 0.5632

48 44 5.3855 6.3946 6.11 6.0485 6.036 8.49 1.73 0.6505

46 2 4.9225 5.8416 5.5563 5.4992 5.4908 9.01 1.33 0.5683

44 97 5.5354 6.9885 6.4206 6.3108 6.2966 12.40 1.60 0.7612

42 64 5.1828 6.3284 5.7547 5.6636 5.6541 15.93 1.66 0.4713

40 65 4.8181 5.7088 5.2158 5.1342 5.1279 20.52 1.58 0.3098

38 82 5.7377 6.5638 6.1863 6.1161 6.1086 15.65 1.67 0.3709

36 79 5.5527 6.5599 6.0654 5.9722 5.9639 18.18 1.62 0.4112

34 46 5.5751 6.4135 6.0495 5.9712 5.9623 16.51 1.88 0.3872

32 75 4.9107 5.98 5.3697 5.2804 5.2717 19.46 1.90 0.361

30 12 5.4255 6.0272 5.5865 5.538 5.5346 30.12 2.11 0.1091

28 94 5.5649 6.4091 5.6923 5.6272 5.6251 51.10 1.65 0.0602

26 78 4.4834 5.2367 4.6659 4.6038 4.6004 34.03 1.86 0.117

24 59 4.9725 6.0724 5.2368 5.1471 5.1422 33.94 1.85 0.1697

22 72 5.4652 6.2483 5.6232 5.5568 5.5538 42.03 1.90 0.0886

20 3 4.7704 5.7739 4.9259 4.8346 4.832 58.71 1.67 0.0616

18 49 4.6623 5.8539 4.8791 4.7699 4.7661 50.37 1.75 0.1038

16 66 5.5656 6.6958 5.7257 5.6326 5.6299 58.15 1.69 0.0643

14 63 5.0822 6.2686 5.2298 5.1304 5.1284 67.34 1.36 0.0462

12 101 4.5771 5.3912 4.6812 4.6045 4.6034 73.68 1.06 0.0263

10 26 4.9665 6.2509 5.1388 5.025 5.0231 66.05 1.10 0.0566

8 13 5.7352 6.3375 5.8111 5.7588 5.758 68.91 1.05 0.0228

6 74 6.1399 6.9511 6.2425 6.1666 6.1655 73.98 1.07 0.0256

4 92 5.3957 6.2531 5.5067 5.4305 5.429 68.65 1.35 0.0333

2 70 5.4999 6.6313 5.6272 5.5363 5.5354 71.41 0.71 0.0355

HUNTER-1A-3T 550°C 1000°C wet wt 100*C wt wt 550° LOI 1000°C residue Depth in cruc. smpl& Dry smpl& smpl& Core ID % % Wt (g) Wt (g) cruc (g) wt (g) cruc (g) cruc (g) section (cm)

71 75 4.9105 6.7319 6.4794 6.453 6.3664 1.68 5.52 1.4559

69 92 5.3956 6.9189 6.6861 6.6538 6.5784 2.50 5.84 1.1828

67 65 4.8182 6.3495 6.1537 6.1438 6.0896 0.74 4.06 1.2714

65 70 5.5005 6.9166 6.7163 6.7086 6.6595 0.63 4.04 1.159

63 67 5.1227 6.6735 6.4391 6.4333 6.3903 0.44 3.27 1.2676

61 72 5.4653 7.0544 6.8349 6.8286 6.7774 0.46 3.74 1.3121 92

59 94 5.5646 7.1445 6.9045 6.8987 6.8466 0.43 3.89 1.282

57 18 5.6042 7.2045 6.9529 6.947 6.9011 0.44 3.40 1.2969

55 2 4.923 6.9789 6.651 6.6413 6.5863 0.56 3.18 1.6633

53 13 5.7354 7.4108 7.0954 7.0693 7.0303 1.92 2.87 1.2949

51 97 5.55351 6.6887 6.2142 6.1514 6.1373 9.51 2.13 0.58379

49 71 4.4426 5.5479 5.3649 5.3568 5.3405 0.88 1.77 0.8979

47 85 5.5614 6.8413 6.6451 6.6312 6.6088 1.28 2.07 1.0474

45 79 5.5529 6.7955 6.4972 6.4603 6.4367 3.91 2.50 0.8838

43 44 5.3858 6.6495 6.2875 6.2386 6.2085 5.42 3.34 0.8227

41 26 4.9664 6.2567 5.8856 5.8398 5.8106 4.98 3.18 0.8442

39 12 5.4254 6.2886 5.9926 5.9616 5.944 5.47 3.10 0.5186

37 66 5.5657 6.3953 5.8773 5.8444 5.8281 10.56 5.23 0.2624

35 46 5.5754 6.2204 5.8261 5.8036 5.791 8.97 5.03 0.2156

33 59 4.9725 5.7691 5.2739 5.2485 5.2348 8.43 4.55 0.2623

31 78 4.4834 5.2476 4.7879 4.7632 4.7498 8.11 4.40 0.2664

29 51 5.1369 5.8537 5.42 5.3972 5.3843 8.05 4.56 0.2474

27 63 5.0819 5.8024 5.3658 5.3416 5.3295 8.52 4.26 0.2476

25 101 4.5773 5.5527 4.9672 4.935 4.9169 8.26 4.64 0.3396

23 3 4.7703 5.475 5.0643 5.0416 5.0268 7.72 5.03 0.2565

21 64 5.1824 5.9832 5.5249 5.4996 5.4816 7.39 5.26 0.2992

19 49 4.6619 5.4479 5.0009 4.9751 4.958 7.61 5.04 0.2961

17 74 6.1403 6.8935 6.4679 6.4442 6.426 7.23 5.56 0.2857

15 82 5.7373 6.6584 6.1379 6.1089 6.0867 7.24 5.54 0.3494

13 73 4.4685 5.2565 4.8306 4.8053 4.7832 6.99 6.10 0.3147

11 58 5.3437 6.3403 5.8017 5.7683 5.7404 7.29 6.09 0.3967

9 56 5.2537 5.9849 5.5869 5.5623 5.5416 7.38 6.21 0.2879

7 89 4.6566 5.4182 4.9946 4.97 4.9492 7.28 6.15 0.2926

5 91 4.4912 5.5234 4.9384 4.9038 4.8778 7.74 5.81 0.3866

3 98 5.0299 5.8899 5.3773 5.348 5.33 8.43 5.18 0.3001

1 77 4.8334 6.0274 5.2841 5.2426 5.2223 9.21 4.50 0.3889

Appendix C

Magnetic Susceptibility

Depth in Lake & Core core section Value (SI) Section (cm) Thompson 0 0.2 1B-3T 0.5 1.8 1 6.2 1.5 7.3 2 5.6 2.5 8.7 3 5.8 3.5 6.1 4 6.8 4.5 7.1 5 7.6 5.5 7.4 6 5.6 6.5 6.1 7 10.5 7.5 12.4 8 15.3 8.5 26.6 9 16.7 9.5 6.1 10 6.3 10.5 7 11 8 11.5 7.5 12 11.2 12.5 28.4 13 32 13.5 24.6 14 24.1 14.5 14.9 15 12.1 15.5 13.9 16 11.8 16.5 5.9 17 0.9 17.5 0.8 18 3.1

18.5 1.7 19 1 19.5 0.4 20 0.9 20.5 0.7 21 1.2 21.5 0.9 22 0.6 22.5 0.4 23 0.6 23.5 2.3 24 8.1 24.5 28 25 17 25.5 18.5 26 18.2 26.5 13.7 27 15.4 27.5 24.5 28 21.3 28.5 8.4 29 6.7 29.5 3 30 1.3 30.5 1.2 31 -0.1 31.5 0.2 32 1.6 32.5 8.8 33 6.2 33.5 3.7 34 11.5 34.5 18 35 16.4 35.5 11.9 36 13.3 36.5 22.3 37 13.1 37.5 10.8 38 13.1 96

38.5 20.4 39 15.3 39.5 1.5 40 0.6 40.5 0.2 41 -0.7 41.5 -0.1 42 -0.9 42.5 -0.2 43 -0.6 43.5 -0.6 44 -1.1 44.5 -0.4 45 -0.8 45.5 -1.2 46 -1.2 46.5 -0.3 47 0.2 47.5 -0.2 48 2.5 48.5 19.5 49 12.9 49.5 5 50 6 50.5 14.3 51 11.7 51.5 4.3 52 6.7 52.5 9 53 12.5 53.5 44.2 54 56.1 54.5 42.2 55 34.4 55.5 36.6 56 -495.7 56.5 38.6 57 38.8 57.5 38.8 58 38.6 97

58.5 35.8 59 33.4 59.5 22.7 60 1.9 60.5 1.4 61 1 61.5 0.6 62 3.1 62.5 1.6 63 0.3 63.5 -0.2 64 0.7 64.5 1 65 1.3 65.5 1.6 66 0.4 66.5 0.4 67 -0.2 67.5 0.4 68 -0.2 68.5 0.5 69 0.4 69.5 0.2 70 1 70.5 1.6 71 2 71.5 2.2 72 3.1 72.5 11.8 73 42.8 73.5 121.8 74 111.3 74.5 63 75 66.5 75.5 64.1 76 55.4 76.5 38.2 77 45.3 77.5 45.3 78 73.5 98

78.5 61.8 79 53.5 79.5 65.1 80 53.9 80.5 55.3 81 37.6 81.5 35.5 82 39.5 82.5 36.9 83 35.9 83.5 26.9 84 30.3 84.5 28.5 85 27.5 85.5 31.7 86 34.5 86.5 41.1 87 46.1 87.5 52 88 63.1 88.5 31.8 89 27.2 89.5 24.3 90 28 90.5 36.7 91 31.1 91.5 33.1 92 31.6 92.5 32.8 93 34 93.5 28.6 94 24 94.5 16.1 95 9.7 95.5 6.2

Stone 0 0.8 1A-3T 0.5 5.2 1 27.5 1.5 35.2 99

2 40.5 2.5 49.3 3 74.8 3.5 109 4 85.4 4.5 80 5 80.6 5.5 70 6 69 6.5 83.1 7 89.1 7.5 91.4 8 74 8.5 74.1 9 71.5 9.5 65.5 10 52.8 10.5 46.7 11 58.3 11.5 60.6 12 60.8 12.5 35.9 13 35.3 13.5 33.3 14 39.2 14.5 40.9 15 31.5 15.5 22.8 16 18.4 16.5 16.9 17 16.7 17.5 18.9 18 24.5 18.5 48.9 19 50.3 19.5 59.2 20 90.8 20.5 78.4 21 91.2 21.5 61.1 100

22 92 22.5 93.5 23 81.5 23.5 72.6 24 75.5 24.5 74.2 25 94.7 25.5 80.7 26 80.4 26.5 79.1 27 80.7 27.5 65 28 59.2 28.5 68.4 29 53.6 29.5 44.8 30 46.3 30.5 36 31 38.2 31.5 38.2 32 41.9 32.5 28.7 33 25 33.5 22.5 34 40 34.5 28.5 35 24.7 35.5 35.5 36 39.7 36.5 17 37 8.1 37.5 5.4 38 6.3 38.5 8.1 39 12.7 39.5 23.4 40 13.7 40.5 23.4 41 48.3 41.5 44.3 101

42 44.3 42.5 40.9 43 53.4 43.5 34.2 44 27.9 44.5 27.6 45 28.8 45.5 23.9 46 19.8 46.5 22.4 47 27.4 47.5 20.6 48 13 48.5 18.8 49 22.2 49.5 19 50 5 50.5 4.6 51 2.9 51.5 6.6 52 16.1 52.5 12.8 53 15.2

Fish 0 0.3 1A-2T 0.5 0 1 0.5 1.5 1.6 2 2.5 2.5 5.9 3 11.6 3.5 19.4 4 28.6 4.5 40.9 5 36.2 5.5 27 6 24 6.5 21.3 7 20.1 7.5 18.4 102

8 19 8.5 25.5 9 18 9.5 17.7 10 19.1 10.5 18.8 11 21.8 11.5 22.4 12 20.7 12.5 20 13 20.1 13.5 20.3 14 19.7 14.5 20.7 15 21.2 15.5 21.8 16 20.8 16.5 21 17 20.4 17.5 19.8 18 17.8 18.5 17.8 19 18.1 19.5 19.9 20 19.6 20.5 21.2 21 18.1 21.5 18 22 18.5 22.5 18.5 23 18.8 23.5 19.1 24 18.3 24.5 18.7 25 19.5 25.5 19.1 26 18.7 26.5 19.2 27 18.4 27.5 16.2 103

28 16.8 28.5 16.7 29 15.1 29.5 15 30 15.7 30.5 17.6 31 18.6 31.5 18.4 32 18.5 32.5 18.7 33 20.8 33.5 21.9 34 20.7 34.5 20.9 35 19.6 35.5 19.5 36 19.3 36.5 18.9 37 18.2 37.5 18.6 38 20.3 38.5 21.8 39 21.9 39.5 22.4 40 22.2 40.5 20.8 41 20.7 41.5 19 42 19.8 42.5 21.8 43 20.5 43.5 20.1 44 18.8 44.5 17.3 45 17.3 45.5 19.3 46 20.6 46.5 19.3 47 20.8 47.5 20.8 104

48 22.5 48.5 22.4 49 22.8 49.5 24 50 22.7 50.5 23.4 51 21.6 51.5 20.4 52 24 52.5 26 53 26.3 53.5 28.2 54 38.6 54.5 32.9 55 35.5 55.5 31.6 56 42.4 56.5 49.1 57 42.2 57.5 29.9 58 21.1 58.5 22.1 59 22.3 59.5 21.2 60 20.8 60.5 20.5 61 13.4 61.5 8.6 62 11.1 62.5 15.5 63 26.1 63.5 28.6 64 38.2 64.5 36.4 65 39.2 65.5 49.5 66 95.2 66.5 169 67 53.9 67.5 53.1 105

68 112.4 68.5 77 69 64.6 69.5 134.6 70 130.7 70.5 71.6 71 44.3 71.5 33.7 72 58.7 72.5 39.9 73 68.7 73.5 101.6 74 39.4 74.5 40.2 75 62.2 75.5 54.7 76 50.8 76.5 60.7 77 63.6 77.5 84.2 78 64.9 78.5 67.5 79 76 79.5 78.2 80 44.2 80.5 28.7 81 21.7 81.5 23.4 82 38.6 82.5 41.3 83 27.2 83.5 22.4 84 11.5 84.5 8.4 85 7.2 85.5 6.8 86 6.8 86.5 7.1 87 7.8 87.5 7.4 106

88 7.1 88.5 8.1 89 9.3 89.5 9.5 90 8.6 90.5 8.4 91 9.8 91.5 10.3 92 11.6 92.5 9.6 93 11.7 93.5 14.3 94 14.7 94.5 20

Bullhead 0 0.1 1B-1T 0.5 0.1 1 -0.5 1.5 -0.6 2 -0.3 2.5 -0.2 3 -0.2 3.5 -0.3 4 -0.4 4.5 -0.6 5 -0.5 5.5 -0.5 6 -0.3 6.5 -0.6 7 -0.9 7.5 -1 8 -0.1 8.5 -0.4 9 -0.6 9.5 0 10 -0.5 10.5 -0.1 11 -0.9 11.5 -1.1 12 -1.9 107

12.5 -1.9 13 -1.5 13.5 -1.4 14 -1.6 14.5 -2 15 -1.8 15.5 -0.9 16 -0.5 16.5 -1.6 17 -1.4 17.5 -0.4 18 -0.6 18.5 -0.6 19 -0.7 19.5 -0.3 20 -0.2 20.5 -0.3 21 -1.5 21.5 -0.9 22 -0.8 22.5 -1.1 23 -1.1 23.5 -1.3 24 -0.6 24.5 -0.6 25 -0.8 25.5 -1 26 -1.5 26.5 -1.3 27 -0.7 27.5 -0.3 28 -0.2 28.5 -0.5 29 -0.2 29.5 0.6 30 1.1 30.5 1 31 0.5 31.5 0.7 32 1.7 108

32.5 0.9 33 1.7 33.5 1.7 34 1.7 34.5 1.3 35 1.4 35.5 1.3 36 1.3 36.5 1 37 1.5 37.5 1.7 38 0.8 38.5 1.7 39 1.4 39.5 1.1 40 1.6 40.5 2.3 41 2.7 41.5 2.2 42 3.1 42.5 1.6 43 1.7 43.5 3.4 44 4.9 44.5 4.7 45 4.1 45.5 4 46 3.5 46.5 3.9 47 5 47.5 4.3 48 5.5 48.5 3.9 49 3.4 49.5 4.5 50 4.1 50.5 4.7 51 3.9 51.5 3.5 52 3.8 109

52.5 3.5 53 3.4 53.5 3.6 54 4 54.5 4.8 55 5.4 55.5 3.7 56 3.9 56.5 3.3 57 2.7 57.5 3.2 58 2.6 58.5 3.6 59 4.6 59.5 3.5 60 2.5 60.5 2.5 61 2.5 61.5 1 62 1.2 62.5 1.9 63 1.9 63.5 1.4 64 2.5 64.5 1.9 65 2.3 65.5 4.2 66 2.6 66.5 2.3 67 2.7 67.5 2.4 68 0.5 68.5 0.3 69 1.8 69.5 1.6 70 3.4 70.5 2.1 71 3.1 71.5 2.4 72 1.4 110

72.5 1.4 73 1.9 73.5 5 74 5 74.5 4.4 75 3 75.5 1 76 1.6 76.5 1.3 77 1.2 77.5 0.7 78 0.3 78.5 0.3 79 0.3 79.5 1.4 80 2.3 80.5 2.8 81 1.8 81.5 2.8 82 3.3 82.5 3.7

Hunter 0 4.5 1A-3T 0.5 16.8 1 21.1 1.5 23.3 2 21.9 2.5 21.2 3 24.6 3.5 27.6 4 23.9 4.5 22.4 5 23.2 5.5 22 6 23.8 6.5 22.9 7 22.1 7.5 22.8 8 21.5 8.5 21.7 111

9 21.1 9.5 21.8 10 22.6 10.5 22.3 11 18.9 11.5 20.1 12 19.3 12.5 19.9 13 18.7 13.5 20.2 14 18.6 14.5 17 15 15.9 15.5 16 16 15.1 16.5 14.6 17 15.5 17.5 16.2 18 15.3 18.5 14.5 19 13.7 19.5 14.6 20 14 20.5 14.1 21 13.1 21.5 11.5 22 11.1 22.5 11.1 23 11 23.5 10.5 24 10.7 24.5 10.2 25 9.2 25.5 9.4 26 10.3 26.5 10.3 27 11.5 27.5 11.7 28 13.6 28.5 12.9 112

29 13.9 29.5 13.5 30 13.5 30.5 13.4 31 20.7 31.5 20.8 32 13.6 32.5 15 33 15.2 33.5 15.3 34 15.3 34.5 15.5 35 11.8 35.5 10.7 36 10.3 36.5 11 37 11.6 37.5 13.2 38 16.7 38.5 25 39 19.4 39.5 12.8 40 8.9 40.5 11.8 41 18.5 41.5 15.9 42 19.6 42.5 28.4 43 28.7 43.5 23.3 44 34.2 44.5 44.4 45 52.8 45.5 78.4 46 38.3 46.5 34.6 47 41.4 47.5 31.5 48 32.5 48.5 27.4 113

49 24.5 49.5 16.8 50 14.7 50.5 20.5 51 25.2 51.5 14.2 52 12.3 52.5 24.4 53 51.7 53.5 59.1 54 48.2 54.5 49.3 55 78.1 55.5 65.6 56 52.2 56.5 45.3 57 29.6 57.5 34.3 58 51.5 58.5 28.5 59 27.4 59.5 45.1 60 51.4 60.5 56.7 61 46.1 61.5 79.3 62 134.6 62.5 165.7 63 151.8 63.5 132.8 64 89.9 64.5 98.1 65 100 65.5 129.3 66 136.4 66.5 106.7 67 97.7 67.5 155 68 116.3 68.5 103.7 114

69 60.7 69.5 61.1

115

Appendix D

Particle Size

116

Lake & Core Depth in core Section section (cm) % Sand % Silt % Clay Thompson 87 98.66547 1.334533 0 1B-3T 81 95.38574 3.598493 1.01577 74 98.09179 1.908214 0 70 33.66413 61.31108 5.024787 62 29.55168 65.46267 4.985638 57 95.87427 3.98166 0.144071 52 35.87176 57.62826 6.499978 43 42.62621 52.89137 4.482415 31 31.4936 61.95303 6.553376 20 20.19638 68.00696 11.79666

Stone 56 81.01881 13.6638 5.317388 1A-3T 52 98.95351 1.04649 0 48 89.29245 9.049138 1.658413 44 79.92444 16.24127 3.834293 40 28.79721 57.6266 13.5762 36 34.34757 52.66824 12.9842 31 16.25822 64.5295 19.21228 27 36.73354 53.79937 9.467089 22 19.31894 60.26432 20.41674 17 9.633295 69.9703 20.3964 12 15.6618 62.58151 21.75668 7 1.659569 72.46607 25.87436 2 12.30338 59.86664 27.82997

Fish 89 86.90499 11.53607 1.558935 1A-2T 87 75.91701 20.43687 3.646111 82 16.95787 72.68973 10.35241 78 26.1851 64.88836 8.926541 77 38.72572 52.86081 8.413473 73 96.04912 3.950883 0 71 92.80757 6.965611 0.226819 66 91.55343 8.402784 0.043789 63 34.33068 61.14204 4.527277 60 32.49739 62.61754 4.885074 58 14.7556 79.35535 5.889056

Bullhead 81 61.44644 31.55893 6.994633

117

1B-3T 79 76.72661 19.16537 4.108021 77 91.54674 6.415374 2.037889 75 87.78383 9.548807 2.66895 73 30.79607 54.30069 14.90324 71 52.99172 37.14205 9.866224 69 99.57432 0.425678 0 67 41.40225 46.20406 12.39369 65 81.36641 14.68586 3.947727 63 77.5158 16.99697 5.487234 61 67.80133 24.51415 7.684524 59 45.98231 37.16613 16.85157 55 54.85064 34.51566 10.63371 51 43.04207 37.50748 19.45045 47 11.16446 61.19706 27.63888 43 27.56998 56.27673 16.15328 39 10.47275 63.77201 25.75524 35 10.82813 65.98958 23.18229 31 8.544045 63.3781 28.07786

Hunter 69 68.67071 25.66028 5.669008 1A-3T 66 94.69485 3.916135 1.389017 63 95.81745 3.215812 0.966738 60 98.31793 1.587888 0.09418 57 96.82095 2.550718 0.628336 54 96.33524 3.228664 0.436091 51 93.08608 4.858611 2.055308 48 85.9541 9.816644 4.229263 45 62.77664 26.05375 11.16961 42 32.80513 48.39941 18.79546 39 11.57214 60.8238 27.60406 36 7.805859 67.11664 25.07749 30 2.713597 67.69282 29.59358 25 1.314731 64.8611 33.82418 20 1.807908 72.03164 26.16046 15 1.905757 65.86884 32.2254 10 8.068959 68.75083 23.18021 5 7.320705 66.23777 26.44153

118

Appendix E

Carbon/Nitrogen

119

Lake & Core Depth in core Section section (cm) %N %C C/N Thompson 82 0.01 1.35 135 1B-3T 72 0.01 10.35 1035 70 0.01 13.32 1332 68 0.01 13.29 1329 66 0.01 13.47 1347 64 0.01 13.28 1328 62 0.02 13.14 657 60 0.02 11.99 600 53 0.01 10.49 1049 51 0.01 10.44 1044 49 0.02 11.39 570 47 0.01 13.09 1309 45 0.02 13.19 660 43 0.03 13.36 445 41 0.01 13.13 1313 39 0.01 12.16 1216 36 0.01 9.93 993 34 0 10.52 n/a 32 0.01 9.45 945 30 0.01 10.68 1068 27 0.01 8.48 848 25 0.01 8.75 875 23 0.01 12.05 1205 21 0.01 12.01 1201 10 0.02 13.12 656

Stone 55 0 4.61 n/a 1A-3T 53 0 5.02 n/a 51 0.01 2.39 239 49 0 2.92 n/a 47 0.01 2.78 278 45 0 7.42 n/a 43 0.01 5.09 509 41 0.01 5.96 596 39 0.02 10.19 509.5 37 0.01 6.42 642 35 0.01 7.81 781 33 0.01 7.7 770

120

31 0.01 7.79 779 29 0.01 6.89 689 27 0 4.32 n/a 25 0.01 6.57 657 23 0.01 4.61 461 21 0.01 5.76 576 19 0.01 5.92 592 17 0.02 8.54 427 15 0.01 7.69 769 13 0.01 7.16 716 11 0.01 6.51 651 9 0.01 4.42 442 7 0.01 5.34 534

Fish 82 0.02 8.39 420 1A-2T 80 0.01 9.98 998 78 0.03 8.23 274 76 0.01 3.23 323 74 0.01 1.34 134 62 0 4.23 n/a 61 0 3.25 n/a 60 0.01 3.31 331 59 0 3.66 n/a 58 0 3.87 n/a 57 0.01 3.57 357 56 0.01 3.78 378 55 0.01 3.87 387 54 0.01 3.92 392 53 0.01 4.38 438 52 0.2 6.03 30.15 51 0.22 5 22.73 50 0.44 7.19 16.34 49 0.65 9.49 14.60 48 0.61 9.18 15.05 47 0.64 9.06 14.16 46 0.62 8.52 13.74 45 0.63 8.88 14.10 44 0.66 9.39 14.23 43 0.75 10.54 14.05

121

Bullhead 82 0.03 0.89 29.67 1B-1T 80 0.01 0.57 57.00 78 0.01 0.26 26.00 76 0 0.27 27.00 74 0.01 0.69 69.00 71 0.02 1.08 54.00 68 0.02 0.57 28.50 66 0.03 0.93 31.00 64 0.02 0.54 27.00 62 0.02 0.93 46.50 60 0.02 1.16 58.00 58 0.03 1.3 43.33 56 0.02 1.06 53.00 54 0.02 1.05 52.50 52 0.04 1.3 32.50 50 0.02 1.12 56.00 48 0.18 2.81 15.61 46 0.17 2.52 14.82 44 0.34 7.18 21.12 42 0.35 5.18 14.80 40 0.64 13.1 20.47 38 0.69 10.12 14.67 36 0.55 8.51 15.47 34 0.63 9.16 14.54 32 0.62 9.34 15.06

Hunter 49 0.01 0.89 89 1A-3T 48 0.01 0.97 97 47 0.01 1.71 171 46 0.01 1.37 137 45 0.02 1.82 91 44 0.03 3.11 103.6667 43 0.02 2.39 119.5 42 0.03 2.95 98.33333 41 0.13 4.04 31.07692 40 0.1 3.28 32.8 39 0.1 3.57 35.7 38 0.12 4.37 36.41667 37 0.24 6.02 25.08333 36 0.27 6.41 23.74074 122

35 0.25 5.44 21.76 34 0.21 5.35 25.47619 33 0.19 4.51 23.73684 32 0.16 3.95 24.6875 32 0.18 4.21 23.38889 31 0.18 3.99 22.16667 30 0.17 4.07 23.94118 29 0.16 4.18 26.125 28 0.18 4.01 22.27778 27 0.16 3.92 24.5 26 0.16 3.91 24.4375

123

Appendix F

Supplementary Data for Optically Stimulated Luminescence Dating

124

Table A. Calculated dose rates and modeled dose rates components

Proportional Modeled Formation Fractional Modeled Thinkness Fractional Dose Rate Dose Rate Total Dose Stratigraphic Location (cm) Contribution (J/kg/ka) (J/kg/ka) Rate (J/kg/ka) UT1605 - Hunter Lake - Fine Sand (150-250 μm) 0.931 ± 0.084 Sand sample layer - gamma 43 of 60 1.000 0.308 0.308 Sand sample layer - beta 1.000 0.603 0.603 Cosmic 1.000 0.020 0.020 UT1605 - Hunter Lake - Medium Sand (250-355 μm) 0.897 ± 0.080 Sand sample layer - gamma 43 of 60 1.000 0.308 0.308 Sand sample layer - beta 1.000 0.569 0.569 Cosmic 1.000 0.020 0.020 UT1606 - Stone Lake - Fine Sand (150-250 μm) 0.753 ± 0.063 Sand sample layer - gamma 41 of 60 1.000 0.240 0.240 Sand sample layer - beta 1.000 0.492 0.492 Cosmic 1.000 0.021 0.021 UT1606 - Stone Lake - Medium Sand (250-355 μm) 0.725 ± 0.060 Sand sample layer - gamma 41 of 60 1.000 0.240 0.240 Sand sample layer - beta 1.000 0.464 0.464 Cosmic 1.000 0.021 0.021 UT 1607 - Thompson Lake - Fine Sand (150-250 μm) 0.769 ± 0.089 Silt above - gamma 23 of 60 0.450 0.175 0.079 Silt above - beta 0.000 0.204 0.000 Sand sample layer - gamma 6 of 60 0.100 0.302 0.030 Sand sample layer - beta 1.000 0.562 0.562 Sandy silt below - gamma 27 of 60 0.450 0.188 0.085 Sandy silt below - beta 0.000 0.230 0.000 Cosmic 1.0000 0.013 0.013 UT 1607 - Thompson Lake - Medium Sand (250-355 μm) 0.737 ± 0.085 Silt above - gamma 23 of 60 0.450 0.175 0.079 Silt above - beta 0.000 0.193 0.000 Sand sample layer - gamma 6 of 60 0.100 0.302 0.030 Sand sample layer - beta 1.000 0.530 0.530 Sandy silt below - gamma 27 of 60 0.450 0.188 0.085 Sandy silt below - beta 0.000 0.217 0.000 Cosmic 1.0000 0.013 0.013 UT1608A - Fish Lake - Fine Sand (150-250 μm) 1.091 ± 0.209 Organic layer above (u0) - gamma 27 of 60 0.450 0.593 0.267 Organic layer above (u0) - beta 0.000 0.989 0.000 Sand sample layer (u1) - gamma 6 of 60 0.100 0.299 0.030 Sand sample layer (u1) - beta 1.000 0.628 0.628 Course sand below (u2) - gamma 16 of 60 0.267 0.284 0.076 Course sand below (u2) - beta 0.000 0.547 0.000 Silty sand below (u3) - gamma 4 of 60 0.067 0.327 0.022 Silty sand below (u3) - beta 0.000 0.556 0.000 Sandy silt below (u4) - gamma 7 of 60 0.116 0.364 0.042 125

Sandy silt below (u4) - beta 0.000 0.591 0.000 Cosmic 1.0000 0.026 0.026 UT1609 - Bullhead Lake - Fine Sand (150-250 μm) 1.335 ± 0.243 Sand and clays above - gamma 28 of 60 0.466 0.557 0.260 Sand and clays above - beta 0.000 0.943 0.000 Sand sample layer - gamma 4 of 47 0.067 0.379 0.025 Sand sample layer - beta 1.000 0.701 0.701 Sand below - gamma 15 of 60 0.250 0.636 0.159 Sand below - beta 0.000 1.035 0.000 2nd sand below - gamma 13 of 60 0.217 0.687 0.149 2nd sand below - beta 0.000 1.116 0.000 Cosmic 1.0000 0.041 0.041

Depths adjusted for sediment compaction during coring; H2O content of 33 ± 3%; BAF of

0.89 used for fine sand samples and 0.84 for medium sand samples.

Table B. Concentration of dosimetrically relevant elements from instrumental neutron activation analysis (INAA). The primary sample layers are indicated in bold. Water depth Sediment K concentration Rb concentration Th concentration U concentration Sample ID (m) depth (m) (ppm) (ppm) (ppm) (ppm) UT1605a 17515 ± 1485 74.53 ± 8.51 8.530 ± 0.776 3.489 ± 0.256 UT1605 8.84 5.87 10094 ± 1017 32.18 ± 5.03 2.193 ± 0.204 0.658 ± 0.058 UT1606a 9667 ± 1033 35.48 ± 4.95 2.290 ± 0.215 1.356 ± 0.106 UT1606 7.99 5.95 8107 ± 732 28.96 ± 2.58 1.033 ± 0.096 0.743 ± 0.062 UT1607a 420 ± 43 0.73 ± 0.51 0.152 ± 0.015 1.981 ± 0.135 UT1607 8.81 9.49 8825 ± 914 29.95 ± 3.79 2.000 ± 0.185 0.936 ± 0.074 UT1607b 899 ± 118 4.45 ± 0.69 0.317 ± 0.030 1.965 ± 0.134 UT1608u0 14228 ± 1233 61.24 ± 6.78 5.007 ± 0.457 2.045 ± 0.162 UT1608Au1 10.27 3.08 10804 ± 988 30.39 ± 3.78 1.488 ± 0.141 0.686 ± 0.061 UT1608u2 9130 ± 952 24.94 ± 2.67 2.086 ± 0.190 0.609 ± 0.049 UT1608Bu3 8516 ± 895 23.15 ± 2.91 3.071 ± 0.281 0.855 ± 0.074 UT1608u4 8011 ± 847 29.60 ± 4.82 2.717 ± 0.251 1.563 ± 0.116 UT1608u5 9600 ± 974 41.50 ± 5.62 4.550 ± 0.415 7.625 ± 0.525 UT1609Aa 13918 ± 1258 52.38 ± 5.27 4.777 ± 0.436 1.780 ± 0.147 UT1609A 2.74 3.14 11178 ± 1180 38.66 ± 4.05 2.800 ± 0.258 1.012 ± 0.093 UT1609Ba 14695 ± 1410 58.73 ± 5.45 5.705 ± 0.519 2.173 ± 0.171 UT1609B 15835 ± 1448 65.28 ± 5.75 6.241 ± 0.565 2.327 ± 0.174 Irradiations for INAA were performed at the Ohio State University Research reactor. INAA data reduction was carried out by Scientific Consulting Services, Dublin, OH.

126

Appendix G

Supplementary Data for Pollen Analysis

127

Table C. Pollen concentrations.

Dziekan/ TPLK- TPLK-2 TPLK-3 WLK-1 WLK-2 HLK-1 HLK-2 HLK-3 Fisher 1

Depth(m) 9.01 8.28 8.13 9.60 9.74 4.82 5.02 5.06 in core

Notes sparse too sparse to analyze

Cupressac 1 3 eae

Pinus 125 1 16 3 4.5 3 4

Picea 74 106 67.5 92 121

Abies 1 1

Populus 1 3

Betula 4 1 2 2 2 1

Ostrya 9 3 9 7 5 2

Corylus 4 2 1 1

Carya 4 9 1 1 3

Tilia

Ulmus 14 2 7 1 1

Alnus 1 3 1 6 1

Juglans 2 2

Quercus 26 13 60 15 5 5 8

Acer 4 17 3 1 1 1

Salix 1 8 3 3 4 1 1

Fraxinus 6 4 7 4 5 5

128

Fagus 1 1 2

Castanea

Nyssa 3

Platanus 1

Rumex

Ambrosia 1 2 6 1 1 3 1

Artemisia 8 2 2 5 11 5

Chenopod 1 2 1 2

Gramineae 1 4 3 2 1 1 2

Cyperacea 17 3 13 12 1 5 e

Typha 2 3 1 other herb 2 2 unknown/ 2 5 3 1 1 3 indetermin ate other 1 2 1 2 aquatics

Composita 4 4 3 4 3 e

Ericaceae

Osmunda 1 other 3 1 1 9 1 trilete spore

Dryopteris 2 1 -type

Isoetes

TOTAL 212 158 159 176 126 150 166

129

TOTAL 199 114 141 152 89 128 152 ARBOREAL

NAP 13 44 18 24 37 22 14 spike 27 120 24 59 100 45 30

AP:NAP 16.30 3.5909 8.8333 7.33333 3.4054 6.818 11.857 77 09 33 333 054 18 14

%NAP 6.132 27.848 11.320 13.6363 29.365 14.66 8.4337 08 1 75 636 079 67 35 concentrat 3454 5793.3 29150 13125.4 5544 1466 24346. ion 8.1 33 237 6.7 67

Dziekan/ TPLK- TPLK-2 TPLK-3 WLK-1 WLK-2 HLK-1 HLK-2 HLK-3 Fisher 1

Cupress 0 0 0 0.56818 0 0 1.8072 182 29

Pinus 58.96 0.6329 10.062 1.70454 3.5714 2 2.4096 23 11 89 545 286 39

Picea 0 46.835 0 60.2272 53.571 61.33 72.891 44 727 429 33 57

Abies 0 0 0 0 0 0.666 0.6024 67 1

Populus 0 0 0 0.56818 0 0 1.8072 182 29

Betula 0 2.5316 0.6289 1.13636 1.5873 1.333 0.6024 46 31 364 016 33 1

Ostrya 4.245 1.8987 5.6603 3.97727 0 3.333 1.2048 28 34 77 273 33 19

Corylus 1.886 0 1.2578 0 0.7936 0.666 0 79 62 508 67

Carya 1.886 0 5.6603 0.56818 0.7936 2 0 79 77 182 508

Tilia 0 0 0 0 0 0 0

130

Ulmus 6.603 1.2658 4.4025 0 0.7936 0 0.6024 77 23 16 508 1

Alnus 0.471 0 0 1.70454 0.7936 4 0.6024 7 545 508 1

Juglans 0.943 0 1.2578 0 0 0 0 4 62

Quercus 12.26 8.2278 37.735 8.52272 3.9682 3.333 4.8192 42 48 85 727 54 33 77

Acer 1.886 0 10.691 1.70454 0.7936 0.666 0.6024 79 82 545 508 67 1

Salix 0.471 5.0632 1.8867 1.70454 3.1746 0.666 0.6024 7 91 92 545 032 67 1

Fraxinus 2.830 2.5316 4.4025 2.27272 0 3.333 3.0120 19 46 16 727 33 48

Fagus 0.471 0 0.6289 1.13636 0 0 0 7 31 364

Castanea 0 0 0 0 0 0 0

Nyssa 0 0 1.8867 0 0 0 0 92

Rumex 0 0 0 0 0 0 0

Ambrosia 0.471 1.2658 3.7735 0.56818 0.7936 2 0.6024 7 23 85 182 508 1

Artemisia 0 5.0632 1.2578 1.13636 3.9682 7.333 3.0120 91 62 364 54 33 48

Chenopod 0.471 0 1.2578 0.56818 1.5873 0 0 7 62 182 016

Gramineae 0.471 2.5316 1.8867 1.13636 0.7936 0.666 1.2048 7 46 92 364 508 67 19

Cyperacea 0 10.759 1.8867 7.38636 9.5238 0.666 3.0120 e 49 92 364 095 67 48

Typha 0.943 1.8987 0 0 0 0 0.6024 4 34 1

131

0 1.2658 0 0 0 1.333 0 23 33

0.943 3.1645 1.8867 0.56818 0.7936 2 0 4 57 92 182 508 other 0.471 1.2658 0 0.56818 1.5873 0 0 aquatics 7 23 182 016

Composita 1.886 2.5316 0 1.70454 3.1746 2 0 e 79 46 545 032 trilete 0 0 0 0 0 0 0 spore

Dryopteris 1.415 0 0.6289 0.56818 7.1428 0.666 0 -type 09 31 182 571 67

Isoetes 0 0 0 0 0 0 0 total 1.415 3.1645 0 0.56818 1.5873 0 0.6024 aquatics 09 57 182 016 1 thermohilo 5.188 0 20.125 3.40909 1.5873 2.666 0.6024 us 68 79 091 016 67 1 boreal 0.943 7.5949 2.5157 4.54545 5.5555 6 1.8072 hardwood 4 37 23 455 556 29 s

pine 58.96 0.6329 10.062 1.70454 3.5714 2 2.4096 23 11 89 545 286 39 spruce 0 46.835 0 60.2272 53.571 61.33 72.891 44 727 429 33 57 oak, elm, 25.94 12.025 46.540 8.52272 3.9682 3.333 4.8192 ash… 34 32 88 727 54 33 77 thermophil 5.188 0 20.125 3.40909 1.5873 2.666 0.6024 ous 68 79 091 016 67 1 hardwood s boreal 0.943 7.5949 2.5157 4.54545 5.5555 6 1.8072 hardwood 4 37 23 455 556 29 s

132

NAP 6.132 27.848 11.320 13.6363 29.365 14.66 8.4337 08 1 75 636 079 67 35

133