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INITIATION OF THE ANNUAL FLOOD PULSE IN TONLE SAP LAKE, CAMBODIA

By

MARY BETH DAY

A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT

OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE

UNIVERSITY OF FLORIDA

2009

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© 2009 Mary Beth Day

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ACKNOWLEDGMENTS

I am indebted to my adviser, Dr. David Hodell for his support and encouragement. I

particularly appreciate his willingness to supervise me from afar for the past year and the

invitation to join him in Cambridge. My committee members Dr. Mark Brenner, Dr. George

Kamenov, and Dr. Ellen Martin provided invaluable feedback that greatly enhanced this thesis,

and Mark willingly served as my surrogate adviser in Dave’s absence. Dr. Mike Binford made

numerous helpful suggestions that guided the early stages of my work. I cannot thank Dr. Jason

Curtis and George Kamenov enough for putting up with me, as I would have no data without

them. Gianna Browne and Jaime Escobar were always willing to help me out in the lab. Dr.

Larry Peterson (University of Miami) generously allowed me the use of his equipment. Dr. Tom

Guilderson (Lawrence Livermore National Laboratory) took care of my radiocarbon analyses.

Dr. Alan Kolata (University of Chicago) was instrumental in getting this project off the ground

and providing funding (from the Marion and Adolph Lichtstern Fund and the Neukom Family

Distinguished Service Professorship). Thanks to the UF Alumni and Grinter Fellowships for

financial assistance. The Department of Geological Sciences office staff were always willing to

cheerfully help, for which I am grateful. Many thanks to my parents for their continued love and

support. Lastly, to my friends near and far, especially my fellow grad students Marie Kurz,

Dylan Miner, Derrick Newkirk and Rich MacKenzie, and my old friends Ryan Lindsay Bartz,

Jeff Kaeli, Jessy Nicastro, Kim Roe, and Katie Stones, thank you for making me laugh, think,

relax, and remain (relatively) sane.

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TABLE OF CONTENTS page

ACKNOWLEDGMENTS.................................................................................................................... 3

LIST OF TABLES................................................................................................................................ 6

LIST OF FIGURES .............................................................................................................................. 7

ABSTRACT .......................................................................................................................................... 8

CHAPTER

1 INTRODUCTION......................................................................................................................... 9

2 BACKGROUND ......................................................................................................................... 11

The Tonle Sap Fishery ................................................................................................................ 11 Review of the Flood Pulse Concept ........................................................................................... 11 Tonle Sap Lake as a Flood Pulse System .................................................................................. 14 Paleolimnologic Studies of Tonle Sap ....................................................................................... 16 Geology of the Tonle Sap Basin ................................................................................................ 17 Radiogenic Isotopes and Sediment Provenance ........................................................................ 18 Controls on C/N Ratios and C and N Stable Isotopes of Lake Sediments .............................. 21

C/N Ratios ............................................................................................................................ 21 Stable Isotope Fractionation and Notation ......................................................................... 22 Stable Carbon Isotopes in Lacustrine Sediments............................................................... 23 Nitrogen Isotopes in Lacustrine Sediments........................................................................ 24

3 OBJECTIVES.............................................................................................................................. 28

4 METHODS .................................................................................................................................. 29

5 RESULTS .................................................................................................................................... 33

Core TS-18-XII-03 ...................................................................................................................... 33 Core CHH-17-XII-03 .................................................................................................................. 35

6 DISCUSSION.............................................................................................................................. 50

Evidence for the Connection ...................................................................................................... 50 Ecologic Implications of the Connection .................................................................................. 51 Timing of the Connection ........................................................................................................... 54 Role of Sediments in the Tonle Sap Ecosystem ........................................................................ 55 Cause of the Connection ............................................................................................................. 55

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What was Tonle Sap Lake like Prior to the Connection? ......................................................... 56 Past and Future Implications of Climate and Human-Induced Changes for Tonle Sap

Lake .......................................................................................................................................... 59

7 CONCLUSIONS ......................................................................................................................... 63

APPENDIX A: ADDITIONAL DATA TABLES .......................................................................... 64

LIST OF REFERENCES ................................................................................................................. 152

BIOGRAPHICAL SKETCH ........................................................................................................... 159

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LIST OF TABLES

Table page 5-1 Radiocarbon dates from core TS-18-XII-03 ......................................................................... 48

5-2 Radiocarbon dates from core CHH-17-XII-03 ..................................................................... 49

A-1 Radiogenic isotope data from core TS-18-XII-03................................................................ 64

A-2 REE concentrations (ppm) from core TS-18-XII-03 ........................................................... 65

A-3 Trace element concentrations (ppm) from core TS-18-XII-03 ........................................... 66

A-4 Stable C and N ratios and weight % C and N for core TS-18-XII-03 ................................ 67

A-5 Stable C and N ratios and weight % C and N for core CHH-17-XII-03 ............................ 68

A-6 Magnetic susceptibility for core TS-18-XII-03 .................................................................... 69

A-7 Magnetic susceptibility for core CHH-17-XII-03 ................................................................ 99

A-8 Scanning XRF data from core TS-18-XII-03. .................................................................... 131

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LIST OF FIGURES

Figure page 1-1 Map of Cambodia ................................................................................................................... 10

2-1 Geologic map of Cambodia ................................................................................................... 27

5-1 87Sr/86Sr, εNd, 207Pb/204Pb, magnetic susceptibility, C/N, δ13C, δ15N, and core photograph for Core TS-18-XII-03. ...................................................................................... 37

5-2 206Pb/204Pb and 208Pb/204Pb ratios for core TS-18-XII-03. ................................................... 38

5-3 Eu anomaly for core TS-18-XII-03. ...................................................................................... 39

5-4 Mn, Mn/Al, Fe, and Fe/Al in core TS-18-XII-03................................................................. 40

5-5 Al, Si and Si/Al in core TS-18-XII-03 .................................................................................. 41

5-6 K, K/Al, Rb, and Rb/Al in core TS-18-XII-03 ..................................................................... 42

5-7 Ca, Ca/Al, Sr, Sr/Al, Ba, and Ba/Al in core TS-18-XII-03 ................................................. 43

5-8 Ti, Ti/Al, Zr, and Zr/Al in core TS-18-XII-03. .................................................................... 44

5-9 Weight %C and weight %N for core TS-18-XII-03. ........................................................... 45

5-10 Sedimentation rates for core TS-18-XII-03 .......................................................................... 46

5-11 Magnetic susceptibility, C/N, δ13C, δ15N, and core photograph for core CHH-17-XII-03. ............................................................................................................................................ 47

6-1 εNd values plotted against 87Sr/86Sr and 207Pb/204Pb ............................................................. 61

6-2 S/Al and Cl/Al from core TS-18-XII-03............................................................................... 62

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Abstract of Dissertation Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy

INITIATION OF THE ANNUAL FLOOD PULSE IN TONLE SAP LAKE, CAMBODIA

By

Mary Beth Day

August 2009 Chair: Michael Perfit Major: Geology

Tonle Sap Lake, Cambodia, possesses one of the most productive inland fisheries in the

world and is a vital natural resource for the country. The lake is connected to the Mekong River

via the Tonle Sap River. Flow in the Tonle Sap River reverses seasonally, with water

discharging from the lake in the dry season and entering the lake during the summer monsoon.

This flood pulse drives the lake’s biological productivity. Sr, Nd, and Pb isotopes and elemental

concentrations in a lake sediment core are used to track changes in the provenance of deposits in

Tonle Sap Lake. The objective of this study was to determine when the lake began to receive

water and sediment input via the Mekong River. The transition from an isolated lake basin to the

Mekong-connected system is marked in the core by shifts to values of ^87Sr/^86Sr,

^207Pb/^204Pb, and epsilon sub Nd that are characteristic of Mekong River sediments, and

increases in magnetic susceptibility and K concentrations. C/N ratios, delta^13C and delta^15N

of bulk organic matter indicate a change in the source of organic matter deposited in the lake.

Radiocarbon dates place the timing of the connection event between 5580 and 2845 ^14C yr BP.

The connection was probably established when the Mekong River changed course as delta

progradation initiated after 6000 yr BP.

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CHAPTER 1 INTRODUCTION

Tonle Sap Lake, the largest freshwater body in Southeast Asia, has played a vital role in

the lives of Cambodians since the emergence of the Khmer Empire in the 9th century AD (Figure

1). The Khmer, who built the city of Angkor, ~20 km north of the lake, depended on Tonle Sap

as a food source and transportation network (Kummu, 2009). Cambodians continue to rely on

the lake today. Fish from Tonle Sap provide the majority of the protein in the Cambodian diet

(Baran, 2005; Hortle et al., 2004).

Tonle Sap is extraordinary for both its role in Cambodian history and its unique hydrology.

The Tonle Sap River links Tonle Sap Lake to the Mekong River. During the dry season

(November-April), water flows from the lake, through the Tonle Sap River, into the Mekong,

and ultimately to the South China Sea. However, during the rainy months of the summer

monsoon (May-October), a buildup of hydraulic head at the confluence of the Mekong and Tonle

Sap Rivers leads to a reversal of flow into the Tonle Sap River, and ultimately into the lake.

Consequently, Tonle Sap Lake undergoes a dramatic seasonal transformation (Figure 1-1).

During the monsoon, mean depth increases from dry season values of 1 – 2 m to >10 m at

maximum flood stage, and the lake area grows five-fold, from 2500 – 3000 km2 to >15,000 km2

(Baran, 2005). Flood pulse systems are known to be highly productive (e.g. Junk et al., 1989;

Junk and Wantzen, 2004; Wantzen et al., 2008), and Tonle Sap is no exception. The Tonle Sap-

Mekong system is one of the largest freshwater fisheries in the world. The floodplain (or

aquatic-terrestrial transition zone (ATTZ)) that surrounds the lake includes wetlands and flooded

forest ecosystems. Nutrients are transferred from the ATTZ to the aquatic environment during

the period of inundation. Furthermore, flooded forests provide food and habitat for many fish

species.

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Figure 1-1. Map of Cambodia. Permanently flooded portion of Tonle Sap Lake is indicated by the darker gray area. Seasonally flooded regions of the lake and Mekong River are indicated by the lighter gray areas. Core TS-18-XII-03 location denoted by a yellow circle. Core CHH-17-XII-03 location denoted by a red circle. The ancient city of Angkor is indicated by a blue square.

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CHAPTER 2 BACKGROUND

The Tonle Sap Fishery

Tonle Sap’s reputation as a highly productive ecosystem stems primarily from knowledge

of its fishery. An estimated 179,000 to 246,000 tons of fish are harvested from the lake each

year, although many researchers consider these figures to be unreliable and far too low (e.g.

Baran, 2005; Hortle et al., 2004). Fish from Cambodian fisheries provide at least 40% to 60%

(Baran, 2005), if not as much as 80% (Hortle et al., 2004) of the protein in the Cambodian diet.

In terms of floodplain fish productivity, Tonle Sap is the highest in the world (Baran, 2005). The

proliferation of fish and other aquatic wildlife has been attributed to the annual flood pulse. The

details of how the flood pulse drives productivity are discussed below. Floodplain vegetation

provides habitat and food for many species of fish. Four hundred and seventy-seven freshwater

fish species are known in Cambodia, and many of these are migratory (Baran, 2005). Much of

the migration is passive, as eggs, fry, and juvenile and adult fish are carried into the lake with

rising floodwaters (Lamberts, 2001). Other species will move into the floodplains to spawn at

the onset of the flooding event (Hortle et al., 2004). Local residents rely on Tonle Sap for far

more than just fish, however. Anything and everything that lives in and around the lake from

vegetation, to shellfish, insects, and reptiles, is used (Lamberts, 2001).

Review of the Flood Pulse Concept

The flood pulse concept (FPC) was first described by Junk et al. (1989) as a means to

describe the relationship between the biotic and abiotic components of a large river-floodplain

system. The prevailing paradigm in river ecology at the time, the river continuum concept

(RCC), was developed for permanent lotic environments and was not appropriate for dynamic

flood pulse systems. According the RCC, a gradient of physical conditions exists between the

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upper reaches of a river and its mouth (Vannote et al., 1980). The biotic communities present at

a given stretch of river depend on the relative longitudinal location along the course of that river.

Biologic production depends on the downstream transport of materials (a process known as

nutrient spiraling) not utilized by communities upstream. In contrast, the FPC emphasizes the

lateral exchange and recycling of nutrients between the floodplain and the main river channel. In

the FPC, the floodplain is defined as,

areas that are periodically inundated by the lateral overflow of rivers or lakes, and/or by direct precipitation or groundwater; the resulting physicochemical environment causes the biota to respond by morphological, anatomical, physiological, phenological, and/or ethological adaptations, and produce characteristic community structures (Junk et al., 1989).

This definition emphasizes the relationship between hydrology and biology in river-floodplain

systems, unlike the classical designation of a floodplain as simply the region inundated by a 100-

year flood. In the FPC literature, the floodplain is often referred to as the aquatic-terrestrial

transition zone (ATTZ) to underscore the dual nature of this component of the river system.

The flood pulse controls river-floodplain systems and their biota, in that the system will

respond to the rate of rise and fall, duration, amplitude, timing, frequency, and predictability of

the flood pulse (Junk et al., 1989). Several processes are known to occur concurrently in the

floodplain as water levels rise (Junk and Wantzen, 2004). These include: mixing of main

channel and floodplain water masses and subsequent elimination of heterogeneities in

temperature and chemistry; input of organic and inorganic material into dissolved and suspended

loads of mainstream water; flooding of the terrestrial environment, decomposition of terrestrial

vegetation, mobilization of material deposited during the terrestrial phase; migration or

adaptation of terrestrial organisms; arrival of aquatic organisms via migration or transport by

floodwaters; incorporation of terrestrial organic matter (OM) into aquatic food webs (Junk and

Wantzen, 2004). Conversely, another suite of simultaneous processes occur in the ATTZ as

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floodwaters recede: water masses and their dissolved and suspended loads that were stored in

the floodplain move into the mainstream; the ATTZ dries out, allowing terrestrial organisms to

return; OM from the overlying water is left behind and assimilated into terrestrial food webs;

aquatic organisms migrate back to permanently flooded areas; floodplain and main channel water

bodies become isolated and develop distinctive physicochemical characteristics and biotic

assemblages (Junk and Wantzen, 2004).

Although certain qualities of main river channels impede primary production (such as

high water depth, large amounts of suspended materials, turbulence, and currents), flood pulse

systems are still highly productive overall because of the tremendous productivity that occurs

within the ATTZ (Junk et al., 1989). Many of the biogeochemical processes that promote

primary production in the floodplain are decoupled from the physicochemical conditions in the

main channel. Productivity in both the aquatic and terrestrial phases of river-floodplain systems

depends on nutrient availability in water and sediments, climatic conditions, and the flood pulse

itself (Junk et al., 1989). Some of the flood pulse-driven processes that affect productivity were

mentioned above. The mechanisms that control nutrient availability are only partially

understood. Although river water is considered the primary source of dissolved inorganic

compounds to the flood plain, many studies have recognized that processes occurring within the

floodplain have a profound impact on water quality (e.g. Junk et al., 1989; Furch and Junk, 1992,

1997). The alternation between aquatic and terrestrial phases expedites OM decomposition in

the ATTZ. During dry periods, OM decays rapidly in the oxidizing conditions. When the area is

resubmerged, these nutrients are transferred to the aquatic system where they can stimulate

productivity. Decomposition of terrestrial vegetation at the beginning of the flood also

contributes to the available nutrient pool in the floodplain (e.g. Furch and Junk, 1992, 1997).

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Groundwater interactions may also affect water chemistry in some river-floodplain systems (e.g.

Junk et al., 1989, Furch and Junk, 1997). The FPC predicts a high production to respiration

ratio, such that in situ production is considerable and minimal OM is introduced from upstream

(Junk et al., 1989). High primary productivity is a prerequisite for significant secondary

production. The “flood pulse advantage” specifically refers to the high fish yields generated by

pulsing systems, in which fish can take advantage of floodplain resources unavailable to fish in

non-pulsing systems (Bayley, 1991).

The FPC applies to lakes as well as rivers, with a few minor adjustments (Wantzen et al.,

2008). As lakes are more depositional in nature than rivers, more OM tends to be stored in the

ATTZ of lakes than in rivers. Alternatively, the erosional tendencies of rivers promote greater

mobilization of floodplain material from the terrestrial to the aquatic environment during

inundation than in lakes. Lake morphology controls the extent of the ATTZ, such that shallow

lakes or lakes with a deep central basin surrounded by a broad, shallow littoral zone will have

extensive floodplains while lakes with steep banks will have a significantly smaller floodplain

region.

Tonle Sap Lake as a Flood Pulse System

Although very little work has been done on flood pulse-related processes within Tonle

Sap, the Mekong River-derived flood pulse is widely recognized as the driving force of

productivity in the lake (e.g. Kummu and Sarkkula, 2008; Lamberts, 2001, 2008; Lamberts and

Koponen, 2008; MRCS/WUP-FIN, 2003; Sarkkula et al., 2004). Hydrologic and productivity

models of the Tonle Sap ecosystem indicate that the following flood pulse-related conditions

maximize fisheries productivity: early arrival of floodwaters and long duration of flooding;

adequate flow from the Tonle Sap River into Tonle Sap Lake to carry larvae and juvenile fish;

high flood level that inundates a large area; maintenance of the plants that live in the inundated

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regions to ensure continued transfer of nutrients; preservation of the influx of sediments and

nutrients carried by the floodwaters into the lake (Sarkkula et al., 2004).

Many aspects of the Tonle Sap flood pulse are vulnerable to anthropogenic modification of

flow patterns (Lamberts, 2008). Of those conditions related to fisheries productivity mentioned

above, all but one will be impacted by damming. If flow through the Mekong becomes highly

regulated, flooding will be minimized. This means the amplitude of the flood pulse will be

diminished, and a smaller area will be inundated. The duration of flooding will also be reduced,

and larvae and young fish may not be transported into the lake.

In addition to fishing, rice cultivation is one of the most important sources of food and

income to residents of the Tonle Sap basin (Keskinen et al., 2005). The success of the rice crop

depends primarily on the flood pulse. Floating rice, one of several varieties cultivated in the

Tonle Sap floodplain, is highly susceptible to changes in the rate of rising waters during the

flood, such that when flood waters rise too quickly, crops will be lost (MRCS/WUP-FIN, 2003;

Keskinen et al., 2005). The plants are unable to grow stems longer than 3.5 m, and they will die

if submerged for too long (MRCS/WUP-FIN, 2003). Another variety, rainfed lowland rice, is

vulnerable to crop loss when floodwaters reach depths greater than 0.5 m or contain high

amounts of suspended sediments (Keskinen et al., 2005). Droughts can also adversely affect rice

production, although the height and rapidity of the flood are the most important factors that

affect rice cultivation (Keskinen et al., 2005).

Although the chemistry of water flowing from the Mekong into Tonle Sap is unlikely to

change considerably if the river is dammed, the biogeochemical processes that occur within the

lake will be altered and this will affect water quality and nutrient dynamics. Furthermore, the

sediment load will likely decrease as dams trap materials upstream. Sediments may be an

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important source of nutrients to floodplain soils as well as lacustrine primary producers

(MRCS/WUP-FIN, 2003; Keskinen et al., 2005).

Paleolimnologic Studies of Tonle Sap

The paleoenvironmental history of Tonle Sap Lake was first investigated in the early 1960s

(Carbonnel, 1963; Carbonnel and Guiscafré, 1965). Nineteen cores were collected from the lake

and analyzed for several physical and chemical properties, including grain size, water content,

iron content, and mineralogy (Carbonnel and Guiscafré, 1965). Two sedimentary facies were

recognized, and named “la vase actuelle” and “la vase ancienne”, or the “present mud” and

“ancient mud”, respectively (Carbonnel, 1963). Carbonnel (1963) attributes the present mud to

deposition under modern conditions, while the ancient mud accreted under significantly different

environmental conditions. A piece of wood found near the bottom of the present mud in one of

the cores was dated to 5720 ± 300 14C yr BP. From this date, the modern Tonle Sap Lake system

was assigned an age of ~5000 years.

Another study, which examined the clay mineralogy of sediments from the Tonle Sap

basin, also proposed that the Mekong River became linked to Tonle Sap around 5500 yrs BP

(Okawara and Tsukawaki, 2002). The same lithologic change observed by Carbonnel (1963)

was noted in the core analyzed by Okawara and Tsukawaki (2002). Below this transition, the

only clay minerals present were kaolinite and smectite. Above the transition, illite and chlorite

were present in addition to kaolinite and smectite. Surface sediments from the Siem Reap River

(a small tributary of the lake) and soils from the alluvial plain near the north shore of the lake

(near Angkor) contained only kaolinite and smectite. Illite, chlorite, kaolinite, and smectite were

all present in suspended sediments from Tonle Sap Lake and surface sediments from the Tonle

Sap River. Since illite and chlorite are not produced locally, they must be the products of

weathering in the Mekong River basin upstream of the Tonle Sap River. They are delivered to

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Tonle Sap Lake by the Tonle Sap River, and appeared in the lake sediment record only after

Tonle Sap Lake and the Mekong River became connected.

Pollen analysis of a sediment core, however, suggested that the lake and the Mekong have

been connected throughout the Holocene (Penny, 2006). The presence of Rhizophora

(mangrove) pollen and Thalassiosira bramaputrae, a diatom that inhabits brackish waters, in the

early Holocene portion of the sediment record indicated higher salinity conditions in and around

the lake at that time. From this, Penny (2006) concluded that more saline conditions must

indicate a connection between Tonle Sap Lake and the South China Sea via the Mekong River,

thus the current hydrologic configuration of the Tonle Sap-Mekong system has been in existence

longer than 5000-5500 years. Penny (2006) does not consider alternate explanations for higher

salinity, such as increased evaporation, or a connection to the South China Sea via the Tonle Sap

and Bassac Rivers rather than the Mekong.

Geology of the Tonle Sap Basin

Although it has been suggested that the Tonle Sap basin may be an 800-ka impact crater

responsible for the Australian Tektite Strewn Field (Hartung and Koeberl, 1994), other

researchers believe the lake was formed by subsidence along a series of northwest to southeast-

trending faults (Hutchison, 1989; Workman, 1997). The lake basin can be divided into four parts

(Douglas, 2005). Quaternary alluvial sediments fill the center of the basin. On the north, the

basin is bounded by the Dong Rek Range, an escarpment of Jurassic sandstone. The southern

edge of the basin is formed by the Cardamom Mountains. Triassic sandstones overlying a

crystalline basement complex create this regional topographic high. Lastly, to the north and east

of the lake, ancient basement rocks outcrop as faulted, low relief structures. The major geologic

units in the Tonle Sap basin are illustrated in Figure 2-1.

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Radiogenic Isotopes and Sediment Provenance

Radiogenic isotope ratios of an element are generally expressed as the ratio of the

radiogenic to non-radiogenic isotope of the same element (e.g. 87Sr/86Sr, 143Nd/144Nd, 206Pb/204Pb,

207Pb/204Pb, 208Pb/204Pb). For ease of reporting, 143Nd/144Nd values are frequently expressed in

terms of εNd:

(2-1)

(CHUR (chondritic uniform reservoir): 143Nd/144Nd = 0.51264).

87Sr is generated by the decay of 87Rb. Variations in Sr isotope composition are the result of

fractionation of parent isotope 87Rb during the differentiation of crust and mantle early in Earth’s

history. Rb has a larger ionic radius than Sr and was preferentially fractionated into the silica-

rich minerals that make up much of the crust. Higher Rb levels in the crust will produce more

87Sr through radioactive decay relative to the mantle. The 87Sr/86Sr ratio of the crust is therefore

higher than the mantle. As a result of this differentiation, it is now possible to distinguish

between rocks formed from partial melting of the mantle and those derived from continental

crust.

Parent isotopes 238U, 235U, and 232Th decay through a complex series of reactions to form

206Pb, 207Pb, and 208Pb, respectively. The U-Th-Pb system functions similarly to the Rb-Sr

system, in that the parent elements (U and Th) are incorporated into the silica-rich minerals that

form the crust. Higher concentrations of U and Th in continental material mean that it will have

more radiogenic Pb than mantle-derived material. Because of their distinct decay constants,

207Pb is a more sensitive tracer of ancient (Precambrian) rocks, while 206Pb is most effective at

distinguishing between younger rocks (Rollinson, 1993). While fractionation in the Rb-Sr and

U-Th-Pb systems preferentially incorporated the parent element (Rb, U or Th) into the crust, in

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the Sm-Nd system, the parent element for 143Nd is 144Sm which is depleted in the crust and

enriched in the mantle. Consequently, 143Nd/144Nd values in the mantle can reach higher

143Nd/144Nd values than those in the crust. A positive εNd value therefore indicates a depleted

mantle source, while a negative εNd value is the result of an enriched continental source.

Sediments derived from continental crust will have higher 87Sr/86Sr and Pb isotope ratios and

more negative εNd than those derived from a mantle source. For any radiogenic isotope, the

abundance in a rock depends on the initial amount of the parent isotope and the length of time

radioactive decay has occurred.

Sr, Nd, and Pb isotopes are commonly used in sediment provenance studies. Although

age of the source rocks is the primary determinant of the radiogenic isotope composition of

sediments, Sr isotope composition is not simply a function of provenance. Weathering

complicates the Sr system. If one material weathers at a faster rate than another does, the

87Sr/86Sr signal of a river will reflect a particular source more than it will reflect the average

87Sr/86Sr of the entire drainage area. Biotite, due to a higher Rb/Sr ratio, will have a more

radiogenic Sr isotopic composition. Plagioclase, on the other hand, has a lower 87Sr/86Sr ratio.

Carbonates are also characterized by low 87Sr/86Sr values, but their Sr concentrations are

typically high because Sr commonly substitutes for Ca. Because they are easily weathered,

carbonates often dominate the riverine 87Sr/86Sr signal. Thus, the 87Sr/86Sr ratio of river water

depends primarily on the relative contribution of carbonate versus silicate weathering in the

drainage basin. The 87Sr/86Sr ratio of river water is known to vary on a seasonal basis in the

Himalayas, as carbonates weather more rapidly during the rainy monsoon season while silicate

dissolution dominates during the dry months (Tipper et al., 2006). Amongst the silicate

minerals, plagioclase is expected to weather more rapidly than biotite (Stille and Shields, 1997).

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However, a study by Blum et al. (1993) of weathering in the Sierra Nevada, California

demonstrated that biotite was the primary source of Sr to river water and was weathering much

more quickly than expected. Rare earth elements (REE), including Nd, are considered largely

immobile in natural waters. During weathering and fluvial sediment transport, fractionation of

Nd isotopes does not occur (Goldstein and Jacobsen, 1987). Thus, unlike Sr, Nd isotopes of

fine-grained sediments are a wholly provenance signal. The utility of Sr in provenance studies is

greatly increased when coupled with other radiogenic isotope systems, particularly Nd. Pb

behaves similarly to Sr, in that early weathering of silicate minerals releases more radiogenic Pb

(e.g. Blum and Erel, 2003).

The Mekong River Basin includes a diverse assemblage of geologic terrains (e.g. Douglas,

2005). Very generally, the uppermost portion of the river (on the eastern Tibetan Plateau) runs

through mostly Mesozoic sedimentary rocks as well as sections of Precambrian metamorphic and

extrusive igneous rocks (Liu et al., 2005). In the middle reach of the river, the bedrock consists

of Paleozoic to Mesozoic sedimentary rocks and intrusive igneous rocks (Liu et al., 2005).

Mesozoic sedimentary rocks and extrusive igneous rocks make up the lower section of the

Mekong basin (Liu et al., 2005). Although both the Mekong and Tonle Sap basins will produce

weathering products with a generally continental-type radiogenic isotope signature (see previous

discussion of the geology of the Tonle Sap Lake basin), the differences between the two terrains

are substantial enough to distinguish them isotopically. For instance, the Mekong basin contains

more sedimentary rocks from the Paleozoic and Precambrian than the Tonle Sap basin, which

should produce higher 87Sr/86Sr and Pb-isotope ratios and more negative εNd values in sediments.

The geochemical character of sediments also depends on the degree of weathering. Weathering

is affected by climate and topography, such that weathering will be more intense in warm and/or

21

wet climates with low relief than cool and/or dry areas with steep terrain. Furthermore,

sediments in Tonle Sap Lake are much closer to their source than most sediment in the lower

Mekong basin, meaning the lake sediments had less opportunity to be altered than the river

sediments.

Controls on C/N Ratios and C and N Stable Isotopes of Lake Sediments

C/N ratios

C/N ratios are used to track changes in the source of OM to sediments (e.g. Meyers, 1997;

Meyers and Ishiwatari, 1993; Meyers and Lallier-Vergès, 1999; and references therein). Plants,

which provide most of the organic matter in lacustrine sediments, can be divided into two types:

vascular and non-vascular. Vascular plants, including terrestrial varieties such as grasses,

shrubs, and trees, as well as aquatic macrophytes, have high C/N ratios because they contain the

carbon-rich and nitrogen-poor compounds cellulose and lignin. Typically, land-derived OM has

C/N ratios greater than 20. Non-vascular plants, such as phytoplankton, have low C/N ratios

because of their high protein and lipid content. Both of these compounds are nitrogen-rich. C/N

ratios for plankton usually fall between 4 and 10, however, in nitrogen-limited conditions, C/N

ratios can be as high as 20 (e.g. Healey and Hendzel, 1980; Hecky et al., 1993; Talbot and

Lærdal, 2000). Most lakes have intermediate C/N values, indicating a mix of terrestrial and

aquatic sources contributes to sedimented OM.

In the majority of laboratory analyses, C/N ratios actually represent Corganic/Ntotal ratios, not

Corganic/Norganic. Inorganic nitrogen concentrations are usually much lower than organic nitrogen

concentrations, so the use of Ntotal does not invalidate the C/N ratio. However, in sediments with

very low OM concentrations (<0.3%), a significant proportion of Ntotal can be Ninorganic, which

would produce erroneously low C/N ratios (Meyers, 1997). Diagenetic effects also have the

potential to alter C/N ratios. Wood deposited in lake sediments often has a C/N ratio noticeably

22

lower than that of modern wood, due to the loss of carbon-rich sugars and lipids (Meyers et al.,

1995). Within the uppermost sediments, degradation of OM can also lead to changes in C/N

ratios. In eutrophic lakes, denitrification of OM by microbes can increase C/N ratios (Sarazin et

al., 1992). In marine sediments, C/N ratios are known to decrease as a result of anaerobic

oxidation of organic matter that produces CO2 and CH4, which escape the sediments and reduce

TOC, while NH4+ produced by ammonification will be retained by the sediments due to

adsorption by clay minerals (Müller, 1977; Lallier-Vergès and Albéric, 1990). The same process

likely occurs in some oligotrophic lakes (Meyers and Lallier-Vergès, 1999). Fortunately, these

alterations rarely modify the C/N ratio enough to eliminate a provenance signal.

Stable isotope fractionation and notation

Stable isotopes of light elements such as C and N behave differently from one another, in

part because of the mass difference between the different isotopes, and also because of

disparities in bond strength. In mass-dependent processes such as evaporation or diffusion, the

lighter isotope will preferentially change phase or diffuse out of a system because it has a greater

velocity than the heavier isotope. Because molecules containing lighter isotopes have lower

dissociation energies and thus more easily broken chemical bonds, lighter isotopes will be

preferentially involved in biological reactions, such as photosynthesis. In all cases, removal of

the lighter isotope means the remaining reservoir will be enriched in the heavier isotope.

Fractionation refers to the process of enrichment and depletion of various reservoirs. Sediments

acquire their isotopic composition from the parent material from which the sediment formed, as

well as fractionation that occurs prior to and after sedimentation.

Isotopic ratios are typically expressed as δ values, which provide a convenient means for

comparing the isotopic ratios of a sample to a standard. δ values are determined using the

following equation:

23

(2-2)

where X = 13C or 15N and R equals the ratio of the heavier isotope to the lighter isotope (e.g.

13C/12C or 15N/14N). A higher (more positive) δ value indicates enrichment in the heavy isotope.

In this study, the V-PDB standard is used to calculate δ13C, and AIR (atmospheric N) to calculate

δ15N.

Stable carbon isotopes in lacustrine sediments

Carbon has two stable isotopes, 12C (98.89%) and 13C (1.11%). One of the most important

fractionation processes in the carbon cycle is photosynthesis, during which primary producers

preferentially incorporate 12C into OM. Three unique photosynthetic pathways exist. They are

distinguished by different rates of CO2 diffusion to the chloroplasts, the use of different enzymes

to drive carboxylation reactions, as well as the degree of C isotope fractionation (Cohen, 2003).

Most plants, especially trees, shrubs, and temperate or cold climate grasses, use the C3 Calvin-

Benson pathway. In C3 plants, a -20‰ shift in δ13C from the inorganic C pool occurs during the

formation of OM. Tropical grasses and sedges use the C4 Hatch-Slack pathway, which produces

a -8 to -12‰ shift. The Crassulacean acid metabolism (CAM) pathway is used by succulents

and generates a -10 to -20‰ shift in δ13C. Accordingly, the OM produced by C3 plants typically

has δ13C values between -25 and -32‰ (mean ~-28‰) while C4 plants generate OM with δ13C

values between -10 and -14‰. Although the C4 pathway is less efficient than the C3 pathway, it

requires less water and is more effective in areas of high evapotranspiration and lower

atmospheric CO2 levels. In paleoclimate records, shifts towards C4 vegetation are believed to

indicate warmer and drier conditions, and/or lower pCO2, while C3 plants are favored during

cooler and wetter periods or at times of higher pCO2.

24

Primary producers in lakes use dissolved CO2 (CO2(aq)) or HCO3- as a source of inorganic

C. Fractionation also occurs during photosynthesis in aquatic environments, such that δ13C

values of phytoplankton OM are usually between -25 and -30‰ when CO2(aq) is the C source.

Since most terrestrially-derived OM is produced by C3 plants, it is rarely possible to distinguish

lake-derived OM from land-derived OM using C isotopes. If aquatic primary producers rely on

HCO3- as a source of inorganic C (this is particularly common in alkaline lakes), they will

generate OM with more positive δ13C values because HCO3- is isotopically heavier than CO2(aq).

In that setting, OM provenance may be determined by C isotopes. Variations in C isotope ratios

also occur between the different compounds that make up OM. For example, in marine

plankton, amino acids have a δ13C value of -17‰ while the lipid fraction δ13C is -28‰ (Degens,

1969).

Cohen (2003) discusses numerous processes that affect the C isotope values in lacustrine

sediment records. These include: changes in the nature of DIC induced by periods of mixing or

stratification or upwelling events, changes in productivity or eutrophication, changes in the

inorganic C source for photosynthesis (CO2(aq) versus HCO3-) brought about by change in

alkalinity, changes in the amount of CO2(aq) resulting from variations in pCO2, shift between C3

and C4 vegetation in the catchment, and diagenetic alterations, which are typically small. In

addition, Brenner et al. (1999) mention other possible factors, such as a shift in the source of OM

(aquatic versus terrestrial), a change in the relative abundance of macrophytes versus

phytoplankton, and a change in the degree of fractionation by phytoplankton during

photosynthesis.

Nitrogen isotopes in lacustrine sediments

Nitrogen also has two stable isotopes, 14N, which comprises 99.634% of N, and 15N.

Nitrogen enters lakes in both organic and inorganic forms that originate in both terrestrial and

25

atmospheric reservoirs, including precipitation (δ15N = ~-5 to 5‰), atmospheric N2 (δ15N = 0‰),

C3 land plants (δ15N = ~1‰), soil OM (δ15N = ~5‰), and dissolved NO3- (δ15N = 7 to 10‰).

Each source of N has a different δ15N value, but N that enters lacustrine systems rarely maintains

this original signal. N often changes states in lakes, which provides a multitude of opportunities

for fractionation to occur. Furthermore, because phytoplankton OM is rich in N (see above

discussion of C/N ratios), N from aquatic sources often dominates the N isotopic signal in

sediments even if terrestrial OM is a greater proportion of the total OM mass. With regard to the

N cycle, phytoplankton can be divided into two types: N2-fixing cyanobacteria, and non-N2-

fixing phytoplankton. Cyanobacteria play a crucial role in aquatic ecosystems, in that they

convert atmospheric N2, which most primary producers are unable to process, into NH3, a

bioavailable form of N. Fractionation is minimal in N-fixation, and cyanobacteria-derived OM

has δ15N values around 0‰. However, other phytoplankton do fractionate N by preferentially

incorporating 14N. This enriches the remaining DIN pool in 15N and yields phytoplankton OM

δ15N values of 2 to 14‰. Provided sufficient N is available, primary production of non-N2-

fixing phytoplankton will control the δ15N of a lake. However, in eutrophic, N-limited systems,

δ15N values will be dominated by N2-fixing cyanobacteria (Gu et al., 1996). Fractionation also

takes place during animal consumption. An increase of 3 to 4‰ occurs in each trophic level.

Cohen (2003) describes several mechanisms that can induce shifts in the δ15N record of

lake sediments, including: changes in productivity or eutrophication (usually associated with an

increase in δ13C), modifications of the volume of the hypolimnion through changes in mixing or

stratification, changes in alkalinity that affect ammonia volatilization, shifts in dominant type of

phytoplankton (N2-fixing cyanobacteria versus non-N-fixing phytoplankton), stratification and

mixing events, changes in the DIN reservoir, denitrification, and diagenetic effects.

26

Anthropogenic activities can have a profound effect on the N cycle of a lake, especially since the

forms of N generated by human actions tend to be highly mobile (Talbot, 2001). In systems

where phytoplankton δ15N values differ from terrestrial vegetation δ15N values (e.g. Pang and

Nriagu, 1977), N isotopes may be used to distinguish sediment OM sources. However, the

frequent fractionation associated with biogeochemical cycling of N means that sediment OM is

unlikely to preserve the precise δ15N signal of its source. This application of N isotopes may not

apply to the majority of lacustrine systems.

27

Figure 2-1. Geologic map of Cambodia. The most prominent units in the Tonle Sap Lake basin

are numbered. 1 – Alluvial fans. 2 – Alluvial plain deposits. 3 – Andesite, andesitic breccia and tuff. 4 – Basalt. 5 – Basaltic plateau deposits. 6 – Black schist, phtanite, sandstone. 7 – Deltaic deposits. 8 – Floodplains. 9 – Formation (sandstone and micro-breccia). 10 – Granite. 11 – Granite or g3-4 coarse grained granite. 12 – Granodiorite. 13 – Lake bed deposits. 14 – No classified rock. 15 – Organic deposits (swamps). 16 – Pediments. 17 – Peneplain laterite deposits. 18 – Rhyolite. 19 – Sandstone. 20 – Sandstone, microbreccia. 21 – Terrace alluvial deposits. 22 – Volcanic deposits.

28

CHAPTER 3 OBJECTIVES

This study will address two questions related to the paleoenvironmental history of Tonle

Sap Lake.

• When did Tonle Sap first begin to receive water and sediment input from the Mekong River?

• How did the lake ecosystem respond to the hydrologic changes associated with the initiation of the annual flood pulse?

To resolve the first question, I measured Sr, Nd, and Pb isotopes and elemental concentrations of

a 14C-dated lake sediment core. As discussed above, the mineralogy and chemistry of weathered

material within the Mekong River drainage basin differ fundamentally from that of the sediments

derived from within the Tonle Sap Lake basin. The second question was addressed by

measuring C/N ratios and stable C and N isotopes of sediment OM.

29

CHAPTER 4 METHODS

In December 2003, two sediment cores were retrieved from Tonle Sap Lake (Figure 1-1).

The first (TS-18-XII-03), 5.85-m in length, was retrieved from a water depth of 4.28 m in the

southeastern part of Tonle Sap Lake. The second core (CHH-17-XII-03), 6.25-m in length, was

taken in 4.0 m of water from Tonle Chmaa, an open area on the northern edge of the main lake

basin. Thirteen cm of material between 5.12 and 5.25 m below lake floor (mblf) was lost on

recovery. Most analyses were completed on core TS-18-XII-03. Given that this core is in the

main lake basin, it was judged to be the better archive of paleoenvironmental change in Tonle

Sap. Magnetic susceptibility of both cores was measured at 0.5-cm intervals using a GEOTEK

MultiSensor Core Logger. The cores were split lengthwise and imaged using a GEOTEK digital

color line-scan camera. Smear slides were used to determine sedimentary component

abundance, including the presence of microfossils. Sediment samples were dried overnight at

60° C in an oven, and ground to a powder.

For determination of elemental concentrations, dried and powdered sediment samples were

ashed at 550°C in an oven for 2.5 hours, then dissolved in a HF-HNO3 mixture in sealed Teflon

vials at ~100°C. Residues were analyzed for trace and rare earth element (REE) concentrations

on an Element2 HR-ICP-MS. Re and Rh were used as internal standards, and several USGS

rock standards (AGV-1, BCR-2, BHVO-1, BIR-1) served as external standards.

Sr, Nd, and Pb were separated for radiogenic isotope analysis using standard

chromatographic methods in a clean laboratory. Radiogenic isotope compositions were

measured on a Nu-Plasma MC-ICP-MS using a protocol for highly precise measurements of

small samples described by Kamenov et al. (2006). According to this methodology, analyte ions

were placed in a small volume and the sample was aspirated in the plasma through a DSN-100

30

desolvation nebulizer. Sr and Nd isotope compositions were measured using the Nu-Plasma

time-resolved analysis (TRA) software with a 0.2-second integration time (300 isotope ratios

acquired per minute). 87Sr/86Sr values were normalized to 86Sr/88Sr = 0.1194 and 87Sr was

corrected for the presence of Rb by subtracting the counts of 87Rb expected given an 87Rb/85Rb

of 0.386. The long-term mean 87Sr/86Sr ratio of the standard NBS 987 is 0.710246 (±0.000030,

2σ). 144Nd, 148Nd, and 150Nd were corrected for mass-bias from Sm using 147Sm/144Sm = 4.88,

147Sm/148Sm = 1.33, and 147Sm/150Sm = 2.03. All measured ratios were normalized to

146Nd/144Nd = 0.7219. The long-term mean 143Nd/144Nd of the standard JNdi-1 was 0.512107

(±0.000021, 2σ). Pb isotope compositions were measured using a Tl normalization technique

(see Kamenov et al., 2004). Pb data are relative to the following values of standard NBS 981:

206Pb/204Pb = 16.937 (±0.004, 2σ), 207Pb/204Pb = 15.490 (±0.003, 2σ), and 208Pb/204Pb = 36.695

(±0.009, 2σ).

To measure weight percent C and N, 3 to 5 mg of bulk sediment were loaded into tin

capsules and placed in an autosampler carousel on a Carlo Erba NA1500 CNS Elemental

Analyzer. First, samples were flash combusted in a quartz column with chromium oxide and

silvered cobaltous/cobaltic oxide and abundant oxygen gas at 1040° C. Next, helium gas

transports the sample gas to a 650° C reduction column of elemental copper to remove oxygen

and a magnesium perchlorate trap to remove water. A 1.5-m gas chromatographic column at 55°

C separates the stream into N2 and CO2 gases, which pass through a thermal conductivity

detector. C/N ratios are expressed as atom ratios.

Stable C and N isotopes were measured by placing 30 to 50 mg of bulk sediment into tin

capsules and loading them in an autosampler carousel on a Costech ECS 4010 Elemental

Combustion System or Carlo Erba NA 1500 CNS Elemental Analyzer. Samples were first flash

31

combusted in a quartz column at 1000° C in the presence of oxygen. A helium carrier stream

then transported the sample gas through a 650° C reduction column of elemental copper to

remove oxygen. To remove water, the effluent stream was passed through a magnesium

perchlorate trap. Next, the sample gas traveled through a ConFlo III or ConFlo II interface

system and into a Finnigan-MAT 252 or a Thermo Finnigan DeltaPlus XL isotope ratio mass

spectrometer running on continuous flow mode. Analytical precision (one standard deviation) is

±0.087‰ for δ13C and ±0.098‰ for δ15N.

Cores were analyzed with an Avaatech XRF (x-ray fluorescence) core scanner at the

University of Miami Rosenstiel School of Marine and Atmospheric Science at 1-cm resolution to

provide high-resolution elemental data. XRF core scanning provides the advantages of being a

non-destructive and relatively rapidly manner of analysis, while providing nearly continuous data

(e.g. Tjallingii et al., 2006). The archive half of a split sediment core was scraped clean to reveal

fresh sediments and create a smooth surface, then covered with Ultralene foil. The foil keeps the

measurement unit from getting contaminated and prevents the sediments from drying out. There

is a tendency for a film of water to condense between the foil and the sediments. The presence

of water can interfere with the measurement of lighter elements like Al and Si (Tjallingii et al.,

2006). Allowing the core to come to room temperature (for approximately one hour) reduces the

likelihood of significant condensation formation.

Radiocarbon dates were obtained on chemically pretreated wood, shell (Corbicula sp.), and

decarbonated bulk sediment samples at the Center for Accelerator Mass Spectrometry at

Lawrence Livermore National Laboratories. Bulk sediment samples were decarbonated using

1N HCl with vortexing to prevent clumping, spun down, decanted and rinsed three times with

Milli-Q water. The sediment was then dried overnight on a heating block and converted to CO2

32

using individual quartz tubes. At depths where wood was dated, bulk sediment from the same

depths was also dated to evaluate the reliability of dates on bulk sediment. The maximum

difference between paired wood and sediment dates was <800 years. Furthermore, there are no

significant carbonate outcrops in the lake catchment that might contribute to hard-water-lake

error. The bulk sediment ages from this core are therefore considered to be reliable.

33

CHAPTER 5 RESULTS

Core TS-18-XII-03

The base of core TS-18-XII-03, ~5.85-4.95 mblf, consists of a highly condensed, orange-

brown mud that underlies a peat layer. From 4.95 to 0.90 mblf, sediments consist of grayish-

brown silty mud. At ~0.90 mblf, there is a transition to reddish-brown silty mud with Corbicula

sp. shells between 0.62 and 0.15 mblf.

All radiogenic isotopes measured in core TS-18-XII-03 changed at ~0.90 mblf (Figure 5-

1). 87Sr/86Sr below this depth range from 0.71508 to 0.71930, while Sr isotope values above 0.90

m fall between 0.71823 and 0.72169. εNd values range from -6.1 to -7.6 below 0.9 mblf, and

between -8.2 and -9.8 above. 207Pb/204Pb values vary between 15.657 and 15.669 below 0.90 m,

and increase to between 15.673 and 15.689 above. 206Pb/204Pb and 208Pb/204Pb ratios of Tonle

Sap sediments were also measured (Figure 5-2). 206Pb/204Pb values become less radiogenic

above ~0.90 mblf, while 208Pb/204Pb values become generally more radiogenic moving upcore.

Below the transition at 0.90 mblf, Tonle Sap sediments display a more negative Eu anomaly than

sediments above 0.90 mblf, which have a REE composition closer to average continental

material than the locally sourced sediments (Figure 5-3). The Eu anomaly (Eu/Eu*) is calculated

with the following equation:

(5-1)

REE concentrations were normalized to PAAS (McLennan, 1989).

Magnetic susceptibility increases above 0.90 mblf by nearly a factor of three (Figure 5-1).

Scanning XRF data reveals that the most abundant elements below 0.90 mblf are (from most to

least abundant elements, with greater than 1000 counts): Fe, Si, Ti, K, Al, Zr, and Ca. Above

34

0.90 mblf, the most abundant elements are (from most to least abundant, with greater than 1000

counts): Fe, Si, K, Ti, Ca, Al, Mn, Zr, and Ba. The 1000 count threshold is an arbitrary

designation. Counts do not translate directly to elemental concentrations. Trends in both relative

elemental abundance and aluminum (Al)-normalized abundances were examined. Normalization

to generally non-reactive elements like Al removes inconsistencies in elemental data resulting

from changes in sedimentation rates, grain size, and OM content, which dilutes the detrital signal

(Horowitz, 1991). Data from ~1.13 and 1.05 mblf were considered unreliable because an uneven

surface that formed when the core was split interfered in XRF measurements. Abundances of Fe

and Mn, both redox sensitive elements, shift in a similar manner (Figure 5-4). Two peaks occur

between 3 and 2 mblf, then abundances increase at 0.90 mblf. Mn/Al and Fe/Al generally

increase above the peaks between 3 and 2 mblf. Al and Si, common in detrital material, have

relatively low abundances in the peat layer (Figure 5-5). Between 5 and 2.5 mblf, abundances

are essentially constant, then they decrease between ~2.5 and 0.90 mblf. Both elements’

abundances increase somewhat at 0.90 mblf. Normalized Si follows the same patterns.

Although both are alkali metals, K and Rb behave somewhat differently (Figure 5-6). The

relative abundance of K increases by an order of magnitude above 0.90 mblf, while Rb gradually

increases from 2.5 to 0 mblf. Both normalized K and Rb increase between 2.5 to 0 mblf.

Alkaline earth metals Ca, Sr, and Ba display similar trends (Figure 5-7). Ca begins to increase at

~2.5 mblf, then reaches its highest abundances above 0.90 mblf. Ca peaks at ~0.60 mblf reflect

the Corbicula layer (Figure 5-4b). Ca/Al behaves in the same manner. Relative abundances of

Sr and Ba are fairly constant below 0.90 mblf, then increase above 0.90 mblf. Normalized

abundances of Sr and Ba show a gradual increase above ~2.5 mblf. Transition metals Ti and Zr

also show similar behavior (Figure 5-8). Relative abundances are low in the peat layer, then

35

increase between ~5 and 2.5 mblf. Ti and Zr decrease from ~2.5 to 0.90 mblf, with the exception

of a peak ~1.5 mblf. Above 0.90 mblf, relative abundances of Ti and Zr are somewhat higher.

Ti/Al and Zr/Al are also low in the peat layer, then relatively stable between ~5 and 2.5 mblf.

Ti/Al and Zr/Al become more variable and slightly lower between 2.5 and 0.90 mblf, then

decrease more above 0.90 mblf. Trace element concentrations measured by ICP-MS (Table A-3)

are generally in agreement with the trends observed in trace elements abundance as measured by

scanning XRF.

C/N (atom) ratios decrease after a peak immediately above the 0.90-mblf transition (Figure

5-1). δ13Cbulk values become more negative, while δ15Nbulk values become more positive (Figure

5-1). Both weight %C and weight %N are highest in the peat layer, increase between 2.5 and

0.90 mblf, and decrease somewhat above 0.90 mblf (Figure 5-9). Sedimentation rate changed

from 2 mm yr-1 below ~0.90 mblf to 0.3 mm yr-1 above (Figure 5-10). These values are

consistent with previously published sedimentation rates for Tonle Sap Lake (modern lake: 0.3

mm yr-1 (Carbonnel, 1963); early-middle Holocene: 2.48 mm yr-1, between 2035 and 610 yrs

BP: 0.06 mm yr-1 (Penny et al., 2005); ~6000 to 5600 yr BP: 1.2 mm yr-1, since ~5600 yr BP:

0.01 mm yr-1 (Core TS96-2) (recalculated from Tsukawaki et al., 1997)). All 14C dates from the

core used in this study are reported in Table 5-1.

Core CHH-17-XII-03

Core CHH-17-XII-03 consists of ~5.75 m of grayish-brown silty mud (6.25 to 0.53 mblf)

overlain by ~0.5 m of reddish-brown silty mud (0.53 to 0 mblf). The grayish-brown mud is

interlayered with peat between 6.25 and 5.40 mblf and contains small pieces of wood between

5.00 and 4.55 mblf. Shells of Corbicula sp. are present between 0.53 and 0.05 mblf. A single

Corbicula shell was found at 5.26 mblf, but it is believed to have fallen downcore during the

coring process. Radiocarbon dates from Corbicula in this core are reported in Table 5-2.

36

In core CHH-17-XII-03, magnetic susceptibility increases by a factor of three at ~0.53

mblf (Figure 5-11). C/N (atom) ratios are variable, but decrease overall upcore. The lowest C/N

values occur above the 0.53 mblf transition. A nearly 5‰ decrease in δ13Cbulk occurs above 0.53

mblf. After a shift to somewhat lower values between 3.0 and 2.5 mblf, δ15Nbulk values become

more positive above 0.53 mblf.

37

Figure 5-1. 87Sr/86Sr, εNd, 207Pb/204Pb, magnetic susceptibility, C/N, δ13C, δ15N, and core photograph for Core TS-18-XII-03. Arrows on the horizontal axes of the 87Sr/86Sr, εNd, and 207Pb/204Pb curves indicate the mean value for the Mekong River, based on published results (see text for citations). Radiocarbon dates are indicated on the far right (green triangle = shell, blue diamond = bulk sediment, red square = wood).

38

A B

Figure 5-2. 206Pb/204Pb (A) and 208Pb/204Pb ratios (B) for core TS-18-XII-03.

39

Figure 5-3. Eu anomaly (Eu/Eu*) for core TS-18-XII-03.

40

Figure 5-4. Mn, Mn/Al, Fe, and Fe/Al in core TS-18-XII-03, as measured by scanning XRF. Mn and Fe abundances are in counts.

41

Figure 5-5. Al, Si and Si/Al in core TS-18-XII-03, as measured by scanning XRF. Al and Si abundances are in counts.

42

Figure 5-6. K, K/Al, Rb, and Rb/Al in core TS-18-XII-03, as measured by scanning XRF. K and Rb abundances are in counts.

43

Figure 5-7. Ca, Ca/Al, Sr, Sr/Al, Ba, and Ba/Al in core TS-18-XII-03, as measured by scanning XRF. Ca, Sr and Ba abundances are

in counts.

44

Figure 5-8. Ti, Ti/Al, Zr, and Zr/Al in core TS-18-XII-03, as measured by scanning XRF. Ti and Zr abundances are in counts..

45

Figure 5-9. Weight %C and weight %N for core TS-18-XII-03.

46

Figure 5-10. Sedimentation rates for core TS-18-XII-03. Shell dates are indicated by green

triangles, wood dates by red squares, and bulk sediment dates by blue diamonds.

47

Figure 5-11. Magnetic susceptibility, C/N, δ13C, δ15N, and core photograph for core CHH-17-XII-03

48

Table 5-1. Radiocarbon dates from core TS-18-XII-03

Sample number Depth (mblf) Material Age

(14C yr BP) ±

CAMS-137174 0.53 Shell 1530 35 CAMS-137172 0.54 Shell 1800 30

CAMS-137173 0.55 Shell 1800 30 CAMS-121346 0.85 - 0.87 Wood 2845 35

CAMS-138882 0.85 - 0.87 Bulk sediment 3605 35 CAMS-140615 1.05 - 1.07 Bulk sediment 5580 40

CAMS-140616 2.22 - 2.24 Bulk sediment 6465 40 CAMS-138883 4.96 - 4.98 Bulk sediment 7545 40 CAMS-121347 4.96 - 4.98 Wood 7570 60

49

Table 5-2. Radiocarbon dates from core CHH-17-XII-03

Sample number Depth (mblf) Material Age

(14C yr BP) ±

CAMS-137168 0.25 Shell 1355 30 CAMS-137169 0.25 Shell 635 30

CAMS-137170 0.27 Shell 1185 30 CAMS-137171 0.48 Shell 705 30

50

CHAPTER 6 DISCUSSION

Evidence for the Connection

The shift in Sr, Nd, and 207Pb/204Pb isotopes at ~0.90 mblf represents a change in the

provenance of sediments deposited in Tonle Sap Lake (Figure 5-1). When compared to isotope

values of Mekong River sediments (Millot et al., 2004; Schimanski et al., 2001; Liu et al., 2007)

and marine sediments from the South China Sea believed to be mostly Mekong derived (Liu et

al., 2005), all values in the Tonle Sap core display a shift towards Mekong River sediment values

beginning at 0.90 mblf, consistent with input of sediments from the Mekong (Figure 6-1). All

Mekong River sediment samples were collected near the mouth of the river, and thus integrate a

radiogenic isotope signature for the entire Mekong basin. Given that the Tonle Sap River joins

the Mekong quite close to the delta region, it is reasonable to assume the isotopic signature for

the entire Mekong basin approximates that of the sediments that enter Tonle Sap Lake via the

Tonle Sap River. Marine sediments from the Vietnamese Shelf contain material from sources

other than the Mekong, but the river does provide most of the material to this region today (Liu

et al., 2005), so the radiogenic isotope values from these marine sediments also serve as a

reliable predictor of the isotopic character of the Mekong-derived sediments that enter Tonle Sap

Lake. According to total suspended solids (TSS) data, 72 % of the modern sediment deposited in

Tonle Sap originates in the Mekong, while only 28% is derived from the lake’s catchment

(Kummu et al., 2008). It was therefore expected that the bulk chemistry of Tonle Sap sediments

would shift toward the Mekong once the connection was established. Accordingly, the

sedimentologic change at ~0.90 mblf is interpreted to represent the transition from an isolated

lake to the modern, river-connected, flood-pulsing Tonle Sap system.

51

Higher K levels in the modern lake sediments (Figure 5-6) are consistent with the results of

Okawara and Tsukawaki (2002), who reported the presence of K-bearing illite in the lake

sediments only above the ~0.90 mblf stratigraphic boundary. Elevated K concentrations may

also be related to the release of nutrients as terrestrial vegetation in the ATTZ decomposes at

times of high water (Furch and Junk, 1997). Greater magnetic susceptibility above 0.90 mblf is

also likely the result of input from the Mekong River (Figure 5-1). Interestingly, although Fe is

the most abundant element through the core, magnetic susceptibility values are quite low. The

Fe-bearing minerals in Tonle Sap sediments must not be strongly magnetic. Clay minerals such

as illite or montmorillonite may explain the presence of Fe without high magnetic susceptibility

(Hunt et al., 1995). The more negative Eu anomaly prior to the connection is likely a product of

the volcanic rocks (basalts and granites) that outcrop within the Tonle Sap Lake basin (Figure 5-

3). This signal becomes undetectable above 0.90 mblf once the Mekong River becomes the

primary source of sediment to the lake. Changes in the relative abundances of several trace

elements (i.e. Zr, Rb, Sr) at 0.90 mblf are also consistent with the introduction of sedimentary

material of a different mineralogic character (Figures 5-6, 5-7, 5-8).

Ecologic Implications of the Connection

Because the ancient Tonle Sap Lake was not a flood pulse system prior to connection with

the Mekong, the ecology of the ancient lake would have been considerably different from the

modern system. Changes in C/N ratios, δ13C and δ15N at 0.90 mblf reflect this transformation

(Figure 5-1). The peak of high C/N immediately after the 0.90 mblf transition may reflect an

initial pulse of terrestrial material at the onset of the flood pulse system. Lower C/N ratios above

0.90 mblf indicate greater relative input of OM from phytoplankton. An increase in the

phytoplankton-derived contribution to sediment OM is likely the result of greater phytoplankton

production within the lake. This result is consistent with predictions made by the FPC. The

52

exchange of nutrients between the permanently flooded lake and the ATTZ promotes greater

autochthonous OM production than would occur in a non-pulsing lake. Increased phytoplankton

production is supported indirectly by the existence of the Tonle Sap fishery. Phytoplankton is

known to be an important food source for adult fish in the Amazon River (Forsberg et al., 1993).

Although piscine food sources have not been extensively studied in Tonle Sap, the fishery could

not exist without the flood pulse advantage of substantial primary production.

The decrease in δ13C above 0.90 mblf also suggests a change in the source of OM

delivered to the lake. Sediments from Tonle Sap contain no carbonate minerals except for the

Corbicula shell layer between 0.15 and 0.62 mblf, thus the δ13Cbulk represents the isotopic

composition of the organic carbon fraction. Diagenetic effects can alter the C isotope ratios of

sediments, in that as the more reactive and 13C-enriched components of OM are lost, the δ13C

will decrease (Meyers and Ishiwatari, 1993). However, this process seems to be significant only

in environments with high OM concentrations, and rarely yields large changes in the C isotopes

of lake sediments. Although enhanced productivity would be consistent with the lower C/N

ratios above 0.90 mblf, the C isotopes do not reflect a productivity signal. However, a change in

the dominant source of OM related to heightened phytoplankton productivity could yield more

negative δ13C values and would be in agreement with lower C/N ratios. Phytoplankton use the

C3 photosynthetic pathway. If a large portion of the vegetation surrounding the lake is C4 plants,

then a greater input of phytoplankton-derived OM would lead to lower δ13C values. At present,

knowledge of the vegetation in the Tonle Sap basin in not sufficient to evaluate the validity of

this hypothesis. Alternatively, if the aquatic vegetation in Tonle Sap changed from macrophyte-

dominated to phytoplankton-dominated, the C isotope record could record this transformation.

In the Amazon (Forsberg et al., 1993) and Orinoco (Hamilton and Lewis, 1992) Rivers, both of

53

which are also tropical flood pulse systems, phytoplankton have significantly more negative δ13C

values than vascular plants. Differences in the C isotope ratios of macrophytes and

phytoplankton could be the result of the aquatic vegetation using HCO3- as a C source while

algae use CO2(aq). In order to verify thes hypotheses, measurements of the C isotopic ratios of

limnetic production as well as vegetation in and around Tonle Sap are needed.

The concurrent increase in δ15N may reflect enhanced productivity, but one would expect

the N isotope signal to be accompanied by an increase in δ13C values. More positive δ15N values

could be the result of a change from predominantly terrestrially-derived OM to phytoplankton-

derived OM (e.g. Pang and Nriagu, 1977), and would be consistent with C/N ratios.

Nonetheless, given the tendency of internal processes to fractionate N within lakes and eliminate

the source signal, this alternative seems improbable. More positive δ15N values could be

attributed to a greater input of OM from higher trophic levels, reflecting the high fish production

that now occurs in Tonle Sap. Although animals rarely contribute to the organic fraction of lake

sediments, N isotopes have been used to track changes in the abundance of Pacific Salmon in

Alaskan lakes (e.g. Kline et al., 1993; Finney et al., 2000). When salmon feed in the ocean, they

acquire an enriched N-isotope signal that is significantly more enriched than that of the terrestrial

N deposited in the lakes (Kline et al., 1993; Finney et al., 2000). Although many of the fish

species in Tonle Sap are also migratory, fish have not been identified as a source of nutrients to

the Tonle Sap ecosystem (e.g. Lamberts, 2001). A more plausible scenario is that the annual

flood pulse transports 15N-enriched soil into the lake. This enriches the DIN pool in the lake, and

contributes to enhanced primary productivity (e.g. Talbot and Lærdal, 2000), both of which can

produce an increase in δ15N.

54

Higher levels of Ba in sediments above 0.90 mblf (Figure 5-7) may be related to increased

productivity. Ba is commonly used as a proxy for paleoproductivity in marine sediment records

(e.g. Klump et al., 2000, and references therein). Although this technique has yet to be applied

to paleolimnologic studies, McGrath et al. (1989) proposed that sinking phytoplankton might

transport Ba to sediments in an English lake, which suggests that Ba may be useful as an

indicator of productivity in lakes as well. Alternatively, some of the Ba may be the result of a

change in sediment provenance.

Timing of the Connection

Radiocarbon dates above and below the stratigraphic boundary at 0.90 mblf indicate that

the modern Tonle Sap Lake system developed between 5580 ± 40 and 3605 ± 35 to 2845 ± 35

14C yr BP. Due to unconsolidated sediments and, in general, the lack of distinct terrestrial

macrofossils, it will be difficult to obtain a more precise determination of the timing of the initial

Tonle Sap-Mekong connection. In all likelihood, uppermost sediment deposited in the ancient

Tonle Sap was resuspended when the lake first received Mekong floodwaters, thus removing part

of the record. That these dates are separated by only 0.2 m also suggests that a portion of the

sediment record was lost. Nonetheless, these 14C dates are in excellent agreement with other

published 14C ages from Tonle Sap. Tsukawaki et al. (1997) obtained an age of 5081 ± 86 14C yr

BP over the sedimentary transition in core TS96-1. For core TS96-2, Tsukawaki et al. (1997)

reported a date of 5620 ± 120 14C yr BP immediately below the transition. Penny et al. (2005)

reported dates of 4990 ± 40 14C yr BP ~25 cm below the stratigraphic change in core S2C1

(marked by both a change in sediment color and an increase in magnetic susceptibility) and 2070

± 40 14C yr BP ~30 cm above it.

Based on magnetic susceptibility, the sedimentologic transition at ~0.53 mblf in core

CHH-17-XII-03 is considered analogous to the 0.90 mblf transition in core TS-18-XII-03,

55

despite a lack 14C dates for the Tonle Chmaa core. Changes in C/N ratios, δ13C and δ15N (Figure

5-11) are of the same nature as those in the Tonle Sap core and reflect the same shift in OM

source. The response to the initiation of the flood pulse was likely consistent throughout the

entire lake basin. This inference is further supported by the increase in magnetic susceptibility

dated between 4090 and 2070 14C yr BP in core S2C1, as reported by Penny et al. (2005).

Role of Sediments in the Tonle Sap Ecosystem

Levels of TSS in Tonle Sap vary with the water level, such that TSS peak at the end of the

dry season (April to June), when water levels are lowest (Campbell et al., 2006; Nagid et al.,

2001; Sarkkula et al., 2004). TSS are consistently higher in the open lake than in the flooded

forest because vegetation traps sediments in the floodplain (Sarkkula et al., 2004). Persistent

resuspension of sediments by wind and wave-induced currents in the modern lake means little

material settles to be deposited permanently. This is reflected in the low sedimentation rate (0.3

mm yr-1) in the modern system. Instead, sediments are removed from the lake via the outflow

and accumulate in the floodplain (MRCS/WUP-FIN, 2003). The turbid nature of the lake,

combined with the dramatic fluctuations in water levels, severely inhibits growth of submerged

aquatic vegetation, despite the near ubiquity of such plants throughout Southeast Asia (Campbell

et al., 2006). Instead, algae and floating mats of herbaceous vegetation are common, as both of

these primary producers out-compete submerged vegetation for light. Sediments brought in with

the floodwaters may also be an important source of nutrients, especially phosphorus, to the lake

(MRCS/WUP-FIN, 2003). Floodplain processes, such as the decomposition of terrestrial

vegetation, are likely a significant source of nutrients as well (Furch and Junk, 1992, 1997).

Cause of the Connection

As the rate of sea level rise decelerated in the early Holocene (8500-6500 yrs BP), modern

delta formation began in many of the world’s rivers (Stanley and Warne, 1994). Sedimentologic

56

studies of the Mekong River confirm that it followed this global trend. Cores from the

Cambodian Mekong River lowlands indicate that delta initiation occurred between 8400 and

6300 yr BP (Tamura et al., 2009). Since ~6000 yr BP, the Mekong River Delta has been

prograding into the South China Sea (Nguyen et al., 2000; Ta et al., 2002, 2004; Tamura et al.,

2009). Delta progradation may have changed the course of the Mekong River, joining it with the

Tonle Sap and Bassac Rivers. At present, the confluence of the Tonle Sap and Mekong Rivers is

tenuous; even a minor shift in the course of the river channel would eliminate the connection

between Tonle Sap Lake and the Mekong. Previously, the lake likely maintained a connection

with the South China Sea through the Tonle Sap and Bassac Rivers. However, there would have

been no means for Mekong floodwaters to be channeled into the lake. Thus, the flood pulse is a

distinctive characteristic of the modern Tonle Sap ecosystem.

What was Tonle Sap Lake like Prior to the Connection?

Based on the pollen and diatom assemblages described by Penny (2006), Tonle Sap

experienced tidal input during the early Holocene when sea level was several meters higher than

present. Thalassiosira bramaputrae, the brackish water diatom was present below 2.3 m (~6400

14C yr BP) and mangrove pollen remained relatively abundant until ~5600 14C yr BP (Penny,

2006). This microfossil record provides a valuable supplement to the geochemical record

presented in this study. Evidence for more saline conditions in Tonle Sap during the early

Holocene does not conflict with any of the data reported in this study in that, a connection to the

South China Sea does not require Tonle Sap to be connected to the Mekong River. The Mekong

has changed course throughout the Quaternary (Rainboth, 1996), and it seems far more likely

that a connection to the South China Sea during the early Holocene would have been via the

Tonle Sap and Bassac Rivers (Campbell et al., 2006). This configuration would still have

57

provided a means for tides to affect the lake and create saline conditions suitable for mangroves

and Thalassiosira bramaputrae.

Prior to being connected to the Mekong, Tonle Sap would have maintained a relatively

stable, shallow depth year-round. Although local monsoon precipitation may have induced a

slight increase in lake water levels each rainy season, without input of floodwaters from the

Mekong, the extreme changes in depth that occur in the lake today would have been impossible.

Higher sedimentation rates (2 mm yr-1) in the ancient Tonle Sap seem to suggest that sediments

settled to the bottom of the lake much more so than today, which have would greatly increased

the clarity of the water column. However, the presence of the diatom Aulacoseira in the early

Holocene portion of Penny’s (2006) Tonle Sap record indicates turbid conditions in the lake.

The shallow depth and large fetch of Tonle Sap, even prior to the connection to the Mekong,

would have promoted resuspension of sediments and created turbid conditions. Although the

C/N and δ13C data could be interpreted to indicate greater production by aquatic macrophytes in

the pre-connection lake, this would not be consistent with turbid conditions. Shallow lakes tend

to exist either as clear water, submerged vegetation-dominated systems, or as turbid systems

dominated by algae or floating plants (Scheffer et al., 1993, 2003).

The paleolimnologic record presented in this study shows two important shifts in the

Holocene history of Tonle Sap Lake. First is the connection event at 0.90 mblf. In addition, a

more subtle change occurs around 2.5 mblf (approximately 6600 14C yr BP), which is illustrated

particularly well by the elemental abundance data (Figures 5-4 to 5-8). Penny (2006) notes the

presence of the saline diatom Thalassiosira bramaputrae in Tonle Sap until ~6400 14C yr BP. If

the disappearance of this diatom indicated the end of tidal influence in the lake, the shift at 2.5

mblf could represent a change to freshwater conditions. However, one might expect a change in

58

the abundance of S or Cl to reflect this transition, given that seawater has significantly higher S

and Cl concentrations than freshwater. Instead, S/Al and Cl/Al increase above 2.5 mblf (Figure

6-2).

More likely, the event at 2.5 mblf represents a modification of the weathering regime

induced by a change in monsoon intensity. The decline of mangrove pollen observed by Penny

(2006) coincided with a change in the floodplain vegetation that occurred around 5600 14C yr

BP. This shift was attributed to greater seasonal variations in lake levels and reduced

precipitation due to weakening of the monsoon (Penny, 2006). A pollen record from a lake in

northeast Cambodia indicated wetter conditions from a strong summer monsoon between 8400

and 5300 14C yr BP, which gave way to a drier climate for much of the remaining mid- to late

Holocene (Maxwell, 2001). This pattern correlates with many records of monsoon intensity

from across Southeast Asia which record a strong monsoon during the early Holocene, followed

by a weakening monsoon in the mid-Holocene, and the onset of significantly drier conditions

around 4 to 3.5 ka (Kale et al., 2003). Although the shift at 2.5 mblf seems to predate the

changes recorded in the pollen records (Maxwell, 2001; Penny, 2006), changes in monsoon

intensity were asynchronous throughout Southeast Asia (Kale et al., 2003) and geochemical

records may respond to climatic forcing at a different rate than biological records. Warmer

and/or wetter conditions promote more intense weathering. Thus, the decrease in relative

abundance of Si, Ti, and Al at ~2.5 mblf (Figures 5-5 and 5-8) likely reflects decreased clay

input, which is consistent with the onset of drier conditions due to a weakening monsoon. As

would be expected, this decrease in detrital input to the lake coincides with an increase in

organic C (Figure 5-9). 87Sr/86Sr also increases somewhat at 2.5 mblf (Figure 5-1), which could

be another indication of a change in the weathering intensity.

59

Past and Future Implications of Climate and Human-Induced Changes for Tonle Sap Lake

The Tonle Sap fishery faces several threats. An increasing human population has led to

overfishing as well as deforestation of the flooded forests as the need for agricultural land and

firewood increased (Hortle et al., 2004). Modifications to the Tonle Sap floodplain will alter the

interaction between the aquatic and terrestrial environments during the flood pulse. Construction

of dams on the Mekong River threatens to alter the hydrology of Tonle Sap. Of greatest concern

is the Lancang Cascade, a series of eight dams currently under construction in southern China.

Although these dams will provide hydroelectric power to local residents, they might also

stabilize water levels in the Lower Mekong Basin. A shorter, smaller flood pulse will lead to

habitat loss and reduced production within Tonle Sap Lake (Hortle et al., 2004). In addition,

dams will prevent migratory fish from traveling upstream to spawn and feed (Hortle et al., 2004).

Most (57%) of the water that enters the lake originates in the Mekong (Kummu et al., 2008).

Consequently, water levels and flow in the river are the primary control on the Tonle Sap flood

pulse.

Natural climate variability and reduced monsoon rainfall in the Mekong catchment would

also diminish the magnitude of the flood pulse. Tree ring data from SE Asia suggest the

abandonment of Angkor Wat in the late 14th and early 15th centuries may have coincided with

weakening of the Asian monsoon (Stone, 2009). This paleolimnologic record provides another

means of evaluating how a drastically different hydrologic regime influences the ecology of

Tonle Sap Lake. If N isotope values prior to the 0.90 mblf transition indicate a lower trophic

status in addition to a different source of organic material, this implies reduced fish production

prior to connection with the Mekong. These findings are consistent with modeling results

(Kummu and Sarkkula, 2008) that suggest alteration of the flood pulse would critically impair

60

the Tonle Sap fishery. This process may have contributed to the ancient abandonment of Angkor

Wat and may detrimentally affect Tonle Sap’s natural resources in the future.

61

A B

Figure 6-1. εNd values plotted against 87Sr/86Sr (A) and 207Pb/204Pb (B). Blue symbols denote lake sediments from below the 0.90-m transition (pre-connection). Green symbols denote lake sediments from above the transition (post-connection). Red triangles (A) are Mekong River values reported by Liu et al. (2005, 2007). Red bar (B) indicates range of εNd values encountered in the literature (Liu et al., 2005, 2007; Schimanski et al., 2001) plotted against the only known 207Pb/204Pb value (Millot et al., 2004).

62

Figure 6-2. S/Al and Cl/Al from core TS-18-XII-03, as measured by scanning XRF.

63

CHAPTER 7 CONCLUSIONS

Sr, Nd, and Pb isotopes were used to identify changes in sediment provenance in a 14C-

dated lake sediment core, and demonstrated that the modern Tonle Sap Lake system is ~3000 -

5000 yr old. At that time, Tonle Sap Lake was transformed from a static, isolated lake basin to a

dynamic, flood-pulse ecosystem. The connection event was likely the result of a change in the

course of the Mekong River related to delta progradation that began after 6000 yr BP. The Tonle

Sap flood pulse created optimal conditions for fish productivity by increasing habitat and food

availability. Reductions in the flood pulse may have occurred in the past from reduced rainfall,

and may occur in the future from damming or climate change. Such changes threaten the fishery

and other aspects of the ecology of Tonle Sap Lake.

64

APPENDIX A ADDITIONAL DATA TABLES

Table A-1. Radiogenic isotope data from core TS-18-XII-03 Depth (mblf)

87Sr/86Sr 143Nd/144Nd 207Pb/204Pb 206Pb/204Pb 208Pb/204Pb

0.03 to 0.05 0.72169 0.51214 15.689 18.747 39.012 0.51 to 0.53 0.72043 0.51216 15.681 18.766 39.020 0.60 to 0.62 0.72056 0.51217 15.683 18.789 39.040 0.72 to 0.74 0.72032 0.51215 15.679 18.783 39.028 0.82 to 0.84 0.71887 0.51217 15.679 18.790 39.028 0.87 to 0.89 0.71823 0.51222 15.673 18.778 39.003 0.95 to 0.97 0.71860 0.51225 15.669 18.798 39.007 1.10 to 1.12 0.71930 0.51229 15.666 18.827 39.018 1.35 to 1.37 0.71909 0.51228 15.667 18.828 39.018 1.60 to 1.62 0.71846 0.51229 15.661 18.811 38.990 2.00 to 2.02 0.71776 0.51229 15.658 18.805 38.982 2.50 to 2.52 0.71581 0.51230 15.657 18.797 38.967 3.00 to 3.02 0.71520 0.51228 15.658 18.790 38.975 3.98 to 4.00 0.71540 0.51228 15.661 18.805 38.989 4.80 to 4.82 0.71556 0.51229 15.663 18.850 39.017 4.98 to 5.00 0.71887 0.51232 15.657 18.939 39.036 5.82 to 5.84 0.71508 0.51230 15.662 18.806 38.994

65

Table A-2. REE concentrations (ppm) from core TS-18-XII-03 Depth (mblf) La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

0.03 to 0.05 43.9 91.8 10.5 38.8 8.06 1.62 7.38 1.14 6.41 1.29 3.69 0.55 3.50 0.53 0.51 to 0.53 46.9 95.1 10.8 39.8 8.01 1.62 7.29 1.11 6.23 1.23 3.55 0.54 3.40 0.52 0.60 to 0.62 32.1 80.9 8.75 33.3 7.09 1.49 6.42 0.98 5.52 1.11 3.17 0.49 3.13 0.47 0.72 to 0.74 39.7 95.6 9.97 37.4 7.80 1.63 7.12 1.07 5.99 1.19 3.41 0.51 3.32 0.51 0.82 to 0.84 43.3 103 11.0 41.8 8.87 1.85 8.20 1.26 7.00 1.40 3.99 0.60 3.79 0.57 0.87 to 0.89 52.5 109 12.3 45.4 9.35 1.87 8.70 1.38 7.86 1.59 4.60 0.70 4.41 0.67 0.95 to 0.97 39.8 83.3 9.61 35.9 7.57 1.50 6.98 1.06 6.09 1.21 3.51 0.54 3.45 0.52 1.10 to 1.12 32.3 72.0 8.30 31.4 6.74 1.28 6.29 0.98 5.70 1.16 3.36 0.52 3.38 0.51 1.35 to 1.37 33.5 71.9 8.34 31.1 6.52 1.24 6.04 0.93 5.48 1.10 3.21 0.51 3.28 0.50 1.60 to 1.62 38.2 77.4 9.10 33.8 7.19 1.30 6.84 1.10 6.54 1.34 3.93 0.60 3.91 0.59 2.00 to 2.02 34.5 69.7 8.20 30.4 6.34 1.15 5.94 0.95 5.65 1.17 3.46 0.55 3.52 0.53 2.50 to 2.52 38.4 78.7 9.18 34.1 7.20 1.30 6.76 1.10 6.53 1.36 4.01 0.63 4.06 0.62 3.00 to 3.02 39.5 85.1 9.50 35.2 7.36 1.35 6.87 1.13 6.87 1.45 4.36 0.68 4.45 0.68 3.98 to 4.00 42.5 88.0 10.1 37.8 7.88 1.47 7.40 1.20 7.23 1.48 4.37 0.68 4.33 0.67 4.80 to 4.82 43.4 95.4 10.6 39.3 8.23 1.55 7.69 1.21 7.06 1.44 4.18 0.66 4.17 0.63 4.98 to 5.00 43.0 92.5 10.5 38.8 8.43 1.26 8.38 1.44 8.90 1.86 5.58 0.88 5.67 0.86 5.82 to 5.84 24.7 50.7 6.06 22.2 4.61 0.81 4.18 0.69 4.25 0.90 2.72 0.44 2.94 0.46

66

Table A-3. Trace element concentrations (ppm) from core TS-18-XII-03 Depth (mblf) Li Sc Ti V Cr Co Ni Cu Zn Ga Rb Sr Y Zr Nb Cs Ba Hf Ta Pb Th U

0.03 to 0.05 73.3 19.5 8539 136 95.3 21.3 56.8 37.6 110 32.1 131 69.0 35.8 136 17.5 14.2 529 3.95 1.43 49.1 20.2 4.29

0.51 to 0.53 69.6 18.4 9235 120 83.2 20.7 49.9 33.0 96.4 26.5 136 76.0 35.7 148 17.8 13.4 460 4.14 1.40 35.2 18.4 4.23

0.60 to 0.62 64.0 18.3 10486 134 90.0 23.6 54.7 35.3 108 25.6 105 92.0 27.6 141 19.6 11.8 485 4.09 1.57 42.9 17.1 4.21

0.72 to 0.74 66.0 19.1 10600 135 92.8 23.0 54.7 35.3 108 26.2 126 92.0 32.6 143 19.5 13.6 464 4.14 1.54 41.7 18.6 4.25

0.82 to 0.84 51.6 16.9 13007 123 88.2 31.8 54.2 37.6 111 20.6 89.4 86.8 38.3 152 23.7 8.88 375 4.41 1.92 46.3 18.9 4.69

0.87 to 0.89 68.0 18.8 14497 126 93.7 25.5 55.2 38.5 87.9 21.0 109 55.1 45.3 195 25.4 11.4 340 5.51 2.06 39.5 22.2 5.41

0.95 to 0.97 67.8 19.6 9783 127 97.3 22.0 56.4 40.9 86.0 26.6 105 58.4 34.9 131 17.7 12.4 295 4.07 1.51 35.6 18.2 4.70

1.10 to 1.12 66.3 19.0 8947 127 98.1 21.1 58.6 39.7 81.0 27.5 91.5 52.2 32.1 133 16.9 11.8 273 4.24 1.47 33.6 17.9 4.92

1.35 to 1.37 62.7 18.4 9440 124 91.8 18.8 52.2 39.0 71.2 25.6 90.1 49.4 30.7 134 18.0 11.5 251 4.21 1.56 33.3 18.4 5.06

1.60 to 1.62 78.2 19.6 9622 123 97.0 17.0 51.3 39.3 59.7 31.3 95.4 27.1 39.6 163 19.0 12.8 253 4.88 1.66 30.9 20.8 5.17

2.00 to 2.02 77.1 19.8 9455 125 96.4 17.6 52.7 37.6 56.4 33.8 93.7 24.2 34.8 153 17.9 12.9 236 4.64 1.56 29.4 20.3 4.91

2.50 to 2.52 65.2 18.1 11674 127 98.4 15.0 43.8 37.0 38.1 20.2 70.2 22.7 39.7 187 21.6 9.76 202 5.55 1.89 28.8 22.0 5.47

3.00 to 3.02 62.0 18.5 13956 139 98.3 12.8 37.8 37.4 27.8 17.2 55.8 24.4 40.9 218 25.4 9.21 188 6.55 2.21 30.8 25.1 6.14

3.98 to 4.00 62.3 18.3 13046 131 91.4 12.5 37.4 37.8 29.0 17.7 64.0 26.7 42.1 198 24.0 9.99 201 5.95 2.06 30.6 25.1 6.01

4.80 to 4.82 49.9 17.1 14206 128 84.2 15.9 40.2 35.6 53.3 18.7 55.0 54.1 40.3 175 26.0 9.11 225 5.54 2.28 32.9 22.3 5.61

4.98 to 5.00 86.2 17.9 9881 105 72.3 11.5 36.1 38.2 60.2 40.5 79.5 25.0 53.4 174 26.8 14.8 233 5.73 2.83 47.0 32.6 9.91

5.82 to 5.84 79.7 18.5 8906 132 102 15.3 45.0 36.0 32.6 36.2 56.4 10.9 27.2 158 16.4 12.8 179 4.80 1.42 25.8 19.0 4.38

67

Table A-4. Stable C and N ratios and weight % C and N for core TS-18-XII-03 Depth (mblf)

δ13C (‰, vs VPDB)

δ15N (‰, vs AIR) Wt. %C Wt. %N

0.03 to 0.05 -28.01 3.14 1.34 0.17 0.38 to 0.40 -26.66 3.70 0.89 0.11 0.51 to 0.53 -25.40 5.27 0.80 0.06 0.60 to 0.62 -26.70 5.28 0.93 0.10 0.75 to 0.77 -26.51 5.64 1.08 0.11 0.87 to 0.89 -23.30 3.97 1.20 0.03 0.95 to 0.97 -21.44 2.54 1.71 0.12 1.10 to 1.12 -22.16 2.72 1.93 0.12 1.35 to 1.37 -22.78 2.49 2.23 0.14 1.44 to 1.46 -23.58 2.93 1.79 0.12 1.60 to 1.62 -23.78 2.27 1.94 0.12 1.84 to 1.86 -25.07 2.95 2.12 0.14 2.00 to 2.02 -24.43 3.41 2.17 0.12 2.30 to 2.32 -24.61 3.28 1.64 0.11 2.50 to 2.52 -20.92 3.79 1.25 0.05 2.84 to 2.86 -24.72 3.56 0.85 0.07 3.00 to 3.02 -24.10 3.48 0.74 0.04 3.34 to 3.36 -24.56 3.07 0.95 0.06 3.84 to 3.86 -24.39 3.16 1.21 0.09 3.98 to 4.00 -22.96 3.10 1.35 0.05 4.34 to 4.36 -23.05 3.09 1.39 0.08 4.80 to 4.82 -25.92 3.27 1.30 0.08 4.98 to 5.00 -28.33 3.05 7.09 0.18 5.75 to 5.77 -25.98 3.14 0.47 0.04 5.82 to 5.84 -22.19 4.06 0.78 0.04

68

Table A-5. Stable C and N ratios and weight % C and N for core CHH-17-XII-03 Depth (mblf)

δ13C (‰, vs VPDB)

δ15N (‰, vs AIR) Wt. %N Wt. %C

0.10 to 0.12 -29.72 3.87 0.44 4.06 0.35 to 0.37 -29.72 4.88 0.21 2.46 0.60 to 0.62 -17.89 1.44 0.17 2.88 0.85 to 0.87 -20.07 1.73 0.16 2.60 1.10 to 1.12 -18.95 1.80 0.17 2.22 1.35 to 1.37 -18.51 1.58 0.17 2.09 1.60 to 1.62 -17.05 1.31 0.16 2.19 1.85 to 1.87 -13.65 1.85 0.11 2.29 2.10 to 2.12 -21.19 2.27 0.20 2.74 2.35 to 2.37 -20.27 2.57 0.13 2.21 2.60 to 2.62 -21.70 2.50 0.13 2.14 2.85 to 2.87 -19.34 3.42 0.09 1.64 3.10 to 3.12 -22.12 3.35 0.05 0.93 3.35 to 3.37 -9.93 3.42 0.04 1.39 3.60 to 3.62 -22.29 3.08 0.03 0.91 3.85 to 3.87 -23.77 3.08 0.06 1.13 4.10 to 4.12 -22.13 2.74 0.06 1.44 4.35 to 4.37 -24.99 3.10 0.05 1.28 4.60 to 4.62 -25.38 2.82 0.08 2.13 4.85 to 4.87 -25.43 2.95 0.06 1.76 5.35 to 5.37 -20.20 3.02 0.07 2.22 5.60 to 5.62 -20.08 3.31 0.07 1.61 5.85 to 5.87 -21.04 3.57 0.06 1.71 6.10 to 6.12 -18.42 3.62 0.07 1.65

69

Table A-6. Magnetic susceptibility for core TS-18-XII-03 Depth (mblf) Magnetic Susceptibility 0.000 0.2 0.005 0.4 0.010 0.6 0.015 0.9 0.020 1.3 0.025 1.9 0.030 2.8 0.035 4.1 0.040 5.7 0.045 7.8 0.050 9.9 0.055 12.1 0.060 14.0 0.065 15.4 0.070 16.7 0.075 17.7 0.080 18.5 0.085 19.4 0.090 20.2 0.095 19.0 0.100 21.8 0.105 22.8 0.110 23.7 0.115 24.6 0.120 25.8 0.125 26.8 0.130 27.8 0.135 28.8 0.140 29.6 0.145 30.3 0.150 30.7 0.155 31.1 0.160 31.3 0.165 31.6 0.170 31.8 0.175 31.9 0.180 32.3 0.185 32.6 0.190 33.0 0.195 33.3

70

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 0.200 33.4 0.205 33.4 0.210 33.4 0.215 33.4 0.220 33.3 0.225 33.3 0.230 33.3 0.235 33.2 0.240 33.2 0.245 33.2 0.250 33.1 0.255 33.2 0.260 33.3 0.265 33.3 0.270 33.2 0.275 33.2 0.280 33.3 0.285 33.2 0.290 33.2 0.295 33.2 0.300 33.1 0.305 32.8 0.310 32.6 0.315 32.2 0.320 31.8 0.325 31.6 0.330 31.5 0.335 31.6 0.340 31.8 0.345 31.9 0.350 32.2 0.355 32.2 0.360 32.4 0.365 32.5 0.370 32.5 0.375 32.5 0.380 32.5 0.385 32.6 0.390 32.6 0.395 32.6

71

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 0.400 32.6 0.405 32.6 0.410 32.5 0.415 32.5 0.420 32.5 0.425 32.5 0.430 32.5 0.435 32.7 0.440 32.8 0.445 32.9 0.450 33.1 0.455 33.2 0.460 33.4 0.465 33.5 0.470 33.6 0.475 33.5 0.480 33.3 0.485 33.1 0.490 32.9 0.495 32.7 0.500 32.5 0.505 32.3 0.510 32.2 0.515 32.1 0.520 32.1 0.525 32.0 0.530 31.8 0.535 31.6 0.540 31.4 0.545 31.1 0.550 30.8 0.555 30.5 0.560 30.1 0.565 29.6 0.570 29.2 0.575 29.0 0.580 29.0 0.585 29.2 0.590 29.6 0.595 30.0

72

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 0.600 30.4 0.605 30.7 0.610 31.2 0.615 31.4 0.620 31.6 0.625 31.8 0.630 31.7 0.635 31.5 0.640 30.9 0.645 30.1 0.650 29.1 0.655 27.9 0.660 27.1 0.665 26.7 0.670 26.8 0.675 27.3 0.680 27.7 0.685 28.0 0.690 28.2 0.695 28.3 0.700 28.2 0.705 27.9 0.710 27.6 0.715 27.1 0.720 26.5 0.725 25.9 0.730 25.2 0.735 24.6 0.740 24.0 0.745 23.3 0.750 22.8 0.755 22.6 0.760 22.3 0.765 22.1 0.770 22.1 0.775 22.1 0.780 22.3 0.785 22.4 0.790 22.6 0.795 22.8

73

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 0.800 23.1 0.805 23.2 0.810 23.4 0.815 23.6 0.820 23.8 0.825 24.0 0.830 24.3 0.835 24.5 0.840 24.7 0.845 25.0 0.850 25.5 0.855 26.0 0.860 26.4 0.865 26.7 0.870 26.8 0.875 26.6 0.880 26.0 0.885 25.3 0.890 24.3 0.895 23.0 0.900 21.7 0.905 20.3 0.910 19.1 0.915 17.9 0.920 17.0 0.925 16.2 0.930 15.5 0.935 14.8 0.940 14.2 0.945 13.3 0.950 12.6 0.955 11.8 0.960 11.0 0.965 10.3 0.970 9.9 0.975 9.4 0.980 9.2 0.985 8.9 0.990 8.6 0.995 8.5

74

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 1.000 8.4 1.005 8.5 1.010 8.5 1.015 8.5 1.020 8.4 1.025 8.0 1.030 7.7 1.035 7.3 1.040 7.1 1.045 6.9 1.050 6.8 1.055 6.7 1.060 6.6 1.065 6.6 1.070 6.6 1.075 6.5 1.080 6.6 1.085 6.6 1.090 6.5 1.095 6.5 1.100 6.5 1.105 6.5 1.110 6.4 1.115 6.5 1.120 6.5 1.125 6.5 1.130 6.5 1.135 6.5 1.140 6.5 1.145 6.4 1.150 6.5 1.155 6.5 1.160 6.5 1.165 6.5 1.170 6.5 1.175 6.6 1.180 6.5 1.185 6.6 1.190 6.6 1.195 6.5

75

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 1.200 6.6 1.205 6.6 1.210 6.6 1.215 6.6 1.220 6.6 1.225 6.6 1.230 6.6 1.235 6.6 1.240 6.5 1.245 6.6 1.250 6.6 1.255 6.6 1.260 6.6 1.265 6.7 1.270 6.7 1.275 6.7 1.280 6.7 1.285 6.6 1.290 6.7 1.295 6.8 1.300 6.8 1.305 6.8 1.310 6.8 1.315 6.9 1.320 6.8 1.325 6.9 1.330 6.9 1.335 6.9 1.340 6.9 1.345 6.9 1.350 6.9 1.355 6.9 1.360 6.9 1.365 6.8 1.370 6.8 1.375 6.8 1.380 6.8 1.385 6.7 1.390 6.8 1.395 6.7

76

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 1.400 6.8 1.405 6.8 1.410 6.8 1.415 6.8 1.420 6.8 1.425 6.9 1.430 6.8 1.435 6.9 1.440 6.9 1.445 6.9 1.450 6.9 1.455 6.9 1.460 7.0 1.465 7.0 1.470 7.0 1.475 7.1 1.480 7.2 1.485 7.1 1.490 7.2 1.495 7.3 1.500 7.4 1.505 7.3 1.510 7.4 1.515 7.4 1.520 7.3 1.525 7.3 1.530 7.2 1.535 7.2 1.540 7.1 1.545 7.1 1.550 7.1 1.555 7.1 1.560 7.0 1.565 7.0 1.570 6.9 1.575 6.9 1.580 6.9 1.585 6.8 1.590 6.8 1.595 6.8

77

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 1.600 6.8 1.605 6.8 1.610 6.0 1.615 6.7 1.620 6.8 1.625 6.8 1.630 6.8 1.635 6.9 1.640 7.0 1.645 7.0 1.650 7.1 1.655 7.1 1.660 7.2 1.665 7.2 1.670 7.3 1.675 7.3 1.680 7.3 1.685 7.4 1.690 7.3 1.695 7.3 1.700 7.4 1.705 7.4 1.710 7.4 1.715 7.4 1.720 7.3 1.725 7.4 1.730 7.3 1.735 7.3 1.740 7.3 1.745 7.3 1.750 7.3 1.755 7.3 1.760 7.3 1.765 7.4 1.770 7.3 1.775 7.4 1.780 7.4 1.785 7.3 1.790 7.3 1.795 7.4

78

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 1.800 7.4 1.805 7.4 1.810 7.4 1.815 7.4 1.820 7.3 1.825 7.3 1.830 7.3 1.835 7.2 1.815 7.5 1.820 7.1 1.825 6.9 1.830 6.8 1.835 6.6 1.840 6.6 1.845 6.7 1.850 6.6 1.855 6.6 1.860 6.7 1.865 6.8 1.870 6.8 1.875 6.9 1.880 6.9 1.885 6.9 1.890 6.9 1.895 6.9 1.900 6.9 1.905 6.6 1.910 6.6 1.915 6.5 1.920 6.5 1.925 6.4 1.930 6.5 1.935 6.5 1.940 6.5 1.945 6.6 1.950 6.6 1.955 6.6 1.960 6.7 1.965 6.7 1.970 6.7

79

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 1.975 6.7 1.980 6.8 1.985 6.7 1.990 6.8 1.995 6.7 2.000 6.7 2.005 6.7 2.010 6.8 2.015 6.7 2.020 6.7 2.025 6.7 2.030 6.7 2.035 6.7 2.040 6.6 2.045 6.7 2.050 6.7 2.055 6.7 2.060 6.7 2.065 6.7 2.070 6.7 2.075 6.8 2.080 6.7 2.085 6.7 2.090 6.8 2.095 6.8 2.100 6.8 2.105 6.8 2.110 6.8 2.115 6.9 2.120 6.8 2.125 6.8 2.130 6.9 2.135 7.0 2.140 7.0 2.145 7.0 2.150 7.1 2.155 7.2 2.160 7.2 2.165 7.3 2.170 7.4

80

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 2.175 7.5 2.180 7.7 2.185 7.8 2.190 8.0 2.195 8.2 2.200 8.4 2.205 8.5 2.210 8.7 2.215 8.9 2.220 9.0 2.225 9.1 2.230 9.2 2.235 9.4 2.240 9.4 2.245 9.3 2.250 9.3 2.255 9.3 2.260 9.2 2.265 9.0 2.270 9.0 2.275 8.8 2.280 8.7 2.285 8.4 2.290 8.3 2.295 8.2 2.300 8.0 2.305 7.9 2.310 7.7 2.315 7.5 2.320 7.5 2.325 7.4 2.330 7.3 2.335 7.3 2.340 7.3 2.345 7.2 2.350 7.3 2.355 7.3 2.360 7.3 2.365 7.3 2.370 7.4

81

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 2.375 7.5 2.380 7.6 2.385 7.6 2.390 7.7 2.395 7.7 2.400 7.7 2.405 7.7 2.410 7.8 2.415 7.7 2.420 7.7 2.425 7.7 2.430 7.7 2.435 7.7 2.440 7.7 2.445 7.7 2.450 7.7 2.455 7.7 2.460 7.8 2.465 7.8 2.470 7.9 2.475 7.9 2.480 7.9 2.485 8.0 2.490 8.0 2.495 8.0 2.500 8.0 2.505 8.1 2.510 8.2 2.515 8.3 2.520 8.5 2.525 8.8 2.530 8.9 2.535 9.2 2.540 9.4 2.545 9.7 2.550 9.9 2.555 10.2 2.560 10.4 2.565 10.6 2.570 10.7

82

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 2.575 10.9 2.580 11.0 2.585 11.0 2.590 11.1 2.595 11.1 2.600 11.2 2.605 11.1 2.610 11.3 2.615 11.3 2.620 11.3 2.625 11.5 2.630 11.6 2.635 11.6 2.640 11.7 2.645 11.7 2.650 11.8 2.655 11.8 2.660 11.7 2.665 11.7 2.670 11.6 2.675 11.4 2.680 11.4 2.685 11.2 2.690 11.1 2.695 11.0 2.700 10.9 2.705 10.8 2.710 10.6 2.715 10.5 2.720 10.4 2.725 10.3 2.730 10.2 2.735 10.0 2.740 9.9 2.745 9.7 2.750 9.9 2.755 9.8 2.760 10.0 2.765 9.9 2.770 10.0

83

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 2.775 9.9 2.780 9.9 2.785 9.9 2.790 9.8 2.795 9.8 2.800 9.9 2.805 10.0 2.810 9.9 2.815 10.0 2.820 10.0 2.825 10.1 2.830 10.1 2.835 10.1 2.840 10.2 2.845 10.3 2.850 10.3 2.855 10.4 2.860 10.4 2.865 10.4 2.870 10.5 2.875 10.4 2.880 10.5 2.885 10.5 2.890 10.4 2.895 10.3 2.900 10.3 2.905 10.3 2.910 10.3 2.915 10.2 2.920 10.2 2.925 10.2 2.930 10.2 2.935 10.2 2.940 10.2 2.945 10.2 2.950 10.3 2.955 10.2 2.960 10.4 2.965 10.4 2.970 10.5

84

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 2.975 10.5 2.980 10.6 2.985 10.6 2.990 10.6 2.995 10.6 3.000 10.7 3.005 10.6 3.010 10.6 3.015 10.6 3.020 10.6 3.025 10.6 3.030 10.6 3.035 10.6 3.040 10.6 3.045 10.6 3.050 10.6 3.055 10.6 3.060 10.6 3.065 10.6 3.070 10.6 3.075 10.6 3.080 10.6 3.085 10.6 3.090 10.6 3.095 10.5 3.100 10.6 3.105 10.6 3.110 10.6 3.115 10.6 3.120 10.6 3.125 10.7 3.130 10.7 3.135 10.6 3.140 10.5 3.145 10.6 3.150 10.4 3.155 10.5 3.160 10.4 3.165 10.5 3.170 10.5

85

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 3.175 10.6 3.180 10.6 3.185 10.6 3.190 10.6 3.195 10.7 3.200 10.6 3.205 10.6 3.210 10.6 3.215 10.6 3.220 10.5 3.225 10.6 3.230 10.6 3.235 10.6 3.240 10.6 3.245 10.5 3.250 10.6 3.255 10.6 3.260 10.6 3.265 10.5 3.270 10.6 3.275 10.6 3.280 10.6 3.285 10.7 3.290 10.6 3.295 10.5 3.300 10.4 3.305 10.3 3.310 10.3 3.315 10.2 3.320 10.2 3.325 10.1 3.330 10.1 3.335 10.1 3.340 10.0 3.345 10.0 3.350 10.0 3.355 10.0 3.360 9.9 3.365 10.0 3.370 10.0

86

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 3.375 10.0 3.380 10.1 3.385 10.1 3.390 10.1 3.395 10.2 3.400 10.1 3.405 10.2 3.410 10.1 3.415 10.1 3.420 10.1 3.425 10.1 3.430 10.0 3.435 10.0 3.440 10.0 3.445 10.0 3.450 10.0 3.455 10.0 3.460 10.0 3.465 10.1 3.470 10.1 3.475 10.1 3.480 10.2 3.485 10.2 3.490 10.2 3.495 10.2 3.500 10.1 3.505 10.2 3.510 10.1 3.515 10.1 3.520 10.1 3.525 10.1 3.530 10.1 3.535 10.1 3.540 10.1 3.545 10.1 3.550 10.1 3.555 10.2 3.560 10.2 3.565 10.3 3.570 10.4

87

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 3.575 10.3 3.580 10.4 3.585 10.5 3.590 10.5 3.595 10.5 3.600 10.5 3.605 10.5 3.610 10.5 3.615 10.5 3.620 10.6 3.625 10.5 3.630 10.5 3.635 10.5 3.640 10.5 3.645 10.5 3.650 10.4 3.655 10.5 3.660 10.5 3.665 10.4 3.670 10.4 3.675 10.3 3.680 10.3 3.685 10.4 3.690 10.3 3.695 10.2 3.700 10.1 3.705 10.1 3.710 9.9 3.715 9.7 3.720 9.4 3.725 9.0 3.730 8.7 3.735 8.4 3.740 8.4 3.745 8.4 3.750 8.6 3.755 8.7 3.760 8.9 3.765 8.9 3.770 8.9

88

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 3.775 8.9 3.780 8.8 3.785 8.8 3.790 8.7 3.795 8.7 3.800 8.7 3.805 8.7 3.810 8.7 3.815 8.7 3.820 8.8 3.825 8.9 3.830 8.9 3.835 8.9 3.840 9.0 3.845 9.0 3.850 9.1 3.855 9.0 3.860 9.0 3.865 9.0 3.870 9.1 3.875 9.0 3.880 9.0 3.885 9.1 3.890 9.0 3.895 9.1 3.900 9.2 3.905 9.2 3.910 9.2 3.915 9.2 3.920 9.2 3.925 9.2 3.930 9.3 3.935 9.2 3.940 9.2 3.945 9.3 3.950 9.2 3.955 9.4 3.960 9.4 3.965 9.4 3.970 9.5

89

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 3.975 9.5 3.980 9.5 3.985 9.6 3.990 9.5 3.995 9.5 4.000 9.5 4.005 9.4 4.010 9.4 4.015 9.4 4.020 9.3 4.025 9.3 4.030 9.3 4.035 9.4 4.040 9.4 4.045 9.3 4.050 9.4 4.055 9.5 4.060 9.5 4.065 9.5 4.070 9.6 4.075 9.5 4.080 9.4 4.085 9.5 4.090 9.4 4.095 9.5 4.100 9.5 4.105 9.5 4.110 9.5 4.115 9.5 4.120 9.5 4.125 9.5 4.130 9.5 4.135 9.5 4.140 9.5 4.145 9.5 4.150 9.5 4.155 9.5 4.160 9.5 4.165 9.5 4.170 9.6

90

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 4.175 9.5 4.180 9.5 4.185 9.5 4.190 9.5 4.195 9.4 4.200 9.3 4.205 9.3 4.210 9.3 4.215 9.2 4.220 9.1 4.225 9.1 4.230 9.0 4.235 8.9 4.240 8.9 4.245 8.9 4.250 8.9 4.255 8.8 4.260 8.9 4.265 8.8 4.270 8.9 4.275 8.8 4.280 8.8 4.285 8.8 4.290 8.8 4.295 8.7 4.300 8.8 4.305 8.7 4.310 8.7 4.315 8.7 4.320 8.7 4.325 8.6 4.330 8.7 4.335 8.7 4.340 8.6 4.345 8.7 4.350 8.6 4.355 8.6 4.360 8.7 4.365 8.7 4.370 8.6

91

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 4.375 8.7 4.380 8.8 4.385 8.7 4.390 8.7 4.395 8.7 4.400 8.7 4.405 8.7 4.410 8.7 4.415 8.6 4.420 8.7 4.425 8.4 4.430 8.6 4.435 8.6 4.440 8.5 4.445 8.6 4.450 8.5 4.455 8.6 4.460 8.6 4.465 8.6 4.470 8.6 4.475 8.7 4.480 8.7 4.485 8.8 4.490 8.8 4.495 8.7 4.500 8.8 4.505 8.9 4.510 8.8 4.515 8.9 4.520 8.9 4.525 8.9 4.530 8.9 4.535 8.9 4.540 8.9 4.545 8.9 4.550 8.9 4.555 8.9 4.560 8.9 4.565 9.0 4.570 9.0

92

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 4.575 8.9 4.580 8.8 4.585 8.9 4.590 8.8 4.595 8.8 4.600 8.8 4.605 8.8 4.610 8.8 4.615 8.7 4.620 8.7 4.625 8.7 4.630 8.7 4.635 8.7 4.640 8.6 4.645 8.7 4.650 8.7 4.655 8.7 4.660 8.7 4.665 8.7 4.670 8.7 4.675 8.6 4.680 8.6 4.685 8.7 4.690 8.6 4.695 8.6 4.700 8.6 4.705 8.4 4.710 8.3 4.715 8.3 4.720 8.2 4.725 8.2 4.730 8.3 4.735 8.4 4.740 8.5 4.745 8.5 4.750 8.7 4.755 8.7 4.760 8.7 4.765 8.7 4.770 8.7

93

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 4.775 8.7 4.780 8.6 4.785 8.6 4.790 8.7 4.795 8.7 4.800 8.7 4.805 8.8 4.810 8.8 4.815 8.8 4.820 8.8 4.825 8.8 4.830 8.8 4.835 8.9 4.840 8.7 4.845 8.7 4.850 8.8 4.855 8.7 4.860 8.6 4.865 8.6 4.870 8.6 4.875 8.5 4.880 8.5 4.885 8.5 4.890 8.3 4.895 8.2 4.900 8.1 4.905 8.0 4.910 7.8 4.915 7.5 4.920 7.2 4.925 6.9 4.930 6.4 4.935 6.0 4.940 5.5 4.945 5.0 4.950 4.6 4.955 4.2 4.960 4.0 4.965 3.8 4.970 3.6

94

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 4.975 3.4 4.980 3.2 4.985 3.1 4.990 2.9 4.995 2.8 5.000 2.7 5.005 2.6 5.010 2.6 5.015 2.6 5.020 2.5 5.025 2.6 5.030 2.5 5.035 2.5 5.040 2.6 5.045 2.6 5.050 2.5 5.055 2.5 5.060 2.6 5.065 2.7 5.070 2.6 5.075 2.6 5.080 2.7 5.085 2.7 5.090 2.7 5.095 2.8 5.100 2.8 5.105 2.8 5.110 2.9 5.115 3.0 5.120 3.1 5.125 3.3 5.130 3.4 5.135 3.4 5.140 3.5 5.145 3.5 5.150 3.6 5.155 3.6 5.160 3.6 5.165 3.5 5.170 3.4

95

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 5.175 3.4 5.180 3.2 5.185 3.1 5.190 3.1 5.195 3.0 5.200 2.9 5.205 2.8 5.210 2.8 5.215 2.8 5.220 2.9 5.225 3.0 5.230 3.0 5.235 3.1 5.240 3.3 5.245 3.4 5.250 3.5 5.255 3.6 5.260 3.7 5.265 3.9 5.270 4.0 5.275 4.1 5.280 4.1 5.285 4.1 5.290 4.2 5.295 4.2 5.300 4.1 5.305 4.2 5.310 4.3 5.315 4.3 5.320 4.4 5.325 4.4 5.330 4.4 5.335 4.5 5.340 4.6 5.345 4.7 5.350 4.8 5.355 4.9 5.360 5.0 5.365 5.1 5.370 5.3

96

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 5.375 5.4 5.380 5.6 5.385 5.7 5.390 5.9 5.395 6.2 5.400 6.3 5.405 6.5 5.410 6.7 5.415 6.8 5.420 6.9 5.425 6.9 5.430 6.9 5.435 6.9 5.440 6.8 5.445 6.7 5.450 6.6 5.455 6.5 5.460 6.4 5.465 6.3 5.470 6.3 5.475 6.2 5.480 6.2 5.485 6.2 5.490 6.2 5.495 6.2 5.500 6.2 5.505 6.3 5.510 6.3 5.515 6.4 5.520 6.6 5.525 6.7 5.530 6.8 5.535 7.0 5.540 7.1 5.545 7.2 5.550 7.3 5.555 7.5 5.560 7.6 5.565 7.7 5.570 7.8

97

Table A-6. Continued Depth (mblf) Magnetic Susceptibility 5.575 7.9 5.580 8.0 5.585 8.2 5.590 8.3 5.595 8.3 5.600 8.5 5.605 8.5 5.610 8.5 5.615 8.4 5.620 8.1 5.625 7.8 5.630 7.2 5.635 6.7 5.640 6.1 5.645 5.5 5.650 4.9 5.655 4.4 5.660 4.0 5.665 3.9 5.670 4.0 5.675 4.3 5.680 4.9 5.685 5.5 5.690 6.3 5.695 7.0 5.700 7.7 5.705 8.3 5.710 8.8 5.715 9.2 5.720 9.6 5.725 9.7 5.730 9.7 5.735 9.7 5.740 9.6 5.745 9.5 5.750 9.5 5.755 9.6 5.760 9.7 5.765 10.0 5.770 10.4

98

Table A-6. Continued 5.775 10.9 5.780 11.5 5.785 12.1 5.790 12.8 5.795 13.5 5.800 14.3 5.805 15.1 5.810 15.8 5.815 16.4

99

Table A-7. Magnetic susceptibility for core CHH-17-XII-03 Depth (mblf) Magnetic Susceptibility 0.000 0.2 0.005 0.3 0.010 0.4 0.015 0.7 0.020 0.8 0.025 1.3 0.030 1.8 0.035 2.6 0.040 3.7 0.045 4.9 0.050 6.4 0.055 7.8 0.060 9.1 0.065 10.2 0.070 11.2 0.075 12.0 0.080 12.7 0.085 13.2 0.090 13.9 0.095 14.4 0.100 14.8 0.105 15.2 0.110 15.5 0.115 15.6 0.120 15.7 0.125 15.7 0.130 15.7 0.135 15.9 0.140 16.0 0.145 16.3 0.150 16.5 0.155 16.8 0.160 16.9 0.165 17.2 0.170 17.4 0.175 17.6 0.180 18.0 0.185 18.4 0.190 18.9

100

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 0.195 19.6 0.200 20.4 0.205 21.4 0.210 22.5 0.215 23.6 0.220 24.6 0.225 25.7 0.230 26.6 0.235 27.2 0.240 27.7 0.245 28.3 0.250 29.0 0.255 29.8 0.260 30.9 0.265 31.9 0.270 33.0 0.275 33.8 0.280 34.4 0.285 34.7 0.290 34.9 0.295 35.1 0.300 35.4 0.305 35.7 0.310 36.1 0.315 36.4 0.320 36.8 0.325 37.0 0.330 37.1 0.335 36.9 0.340 36.6 0.345 36.1 0.350 35.7 0.355 35.2 0.360 34.9 0.365 34.9 0.370 35.2 0.375 35.7 0.380 36.1 0.385 36.0

101

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 0.390 35.3 0.395 34.3 0.400 33.2 0.405 32.4 0.410 31.9 0.415 31.5 0.420 31.2 0.425 31.1 0.430 30.9 0.435 30.8 0.440 30.8 0.445 30.7 0.450 30.5 0.455 30.4 0.460 30.3 0.465 30.2 0.470 30.1 0.475 29.9 0.480 29.9 0.485 29.8 0.490 29.8 0.495 30.0 0.500 30.2 0.505 30.3 0.510 30.5 0.515 30.8 0.520 31.3 0.525 31.9 0.530 32.6 0.535 33.1 0.540 33.3 0.545 32.9 0.550 31.7 0.555 30.2 0.560 28.4 0.565 26.4 0.570 24.3 0.575 22.4 0.580 20.8

102

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 0.585 19.6 0.590 18.6 0.595 17.5 0.600 16.7 0.605 15.8 0.610 15.2 0.615 14.7 0.620 14.4 0.625 14.1 0.630 13.9 0.635 13.7 0.640 13.4 0.645 13.1 0.650 12.7 0.655 12.2 0.660 11.8 0.665 11.4 0.670 11.1 0.675 10.8 0.680 10.5 0.685 10.4 0.690 10.2 0.695 10.1 0.700 9.9 0.705 9.8 0.710 9.7 0.715 9.6 0.720 9.5 0.725 9.6 0.730 9.5 0.735 9.5 0.740 9.5 0.745 9.4 0.750 9.4 0.755 9.3 0.760 9.3 0.765 9.4 0.770 9.4 0.775 9.5

103

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 0.780 9.5 0.785 9.6 0.790 9.6 0.795 9.7 0.800 9.7 0.805 9.8 0.810 9.8 0.815 9.9 0.820 10.0 0.825 10.0 0.830 10.0 0.835 10.1 0.840 10.1 0.845 10.1 0.850 10.1 0.855 10.0 0.860 9.9 0.865 9.8 0.870 9.6 0.875 9.4 0.880 9.3 0.885 9.2 0.890 9.0 0.895 8.8 0.900 8.8 0.905 8.7 0.910 8.6 0.915 8.5 0.920 8.4 0.925 8.4 0.930 8.4 0.935 8.5 0.940 8.5 0.945 8.5 0.950 8.5 0.955 8.5 0.960 8.6 0.965 8.5 0.970 8.6

104

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 0.975 8.6 0.980 8.6 0.985 8.6 0.990 8.6 0.995 8.6 1.000 8.6 1.005 8.6 1.010 8.5 1.015 8.5 1.020 8.4 1.025 8.3 1.030 8.2 1.035 8.1 1.040 8.0 1.045 7.9 1.050 7.9 1.055 7.8 1.060 7.7 1.065 7.7 1.070 7.7 1.075 7.7 1.080 7.6 1.085 7.6 1.090 7.7 1.095 7.7 1.100 7.6 1.105 7.6 1.110 7.6 1.115 7.6 1.120 7.7 1.125 7.7 1.130 7.7 1.135 7.7 1.140 7.7 1.145 7.8 1.150 7.8 1.155 7.9 1.160 7.9 1.165 7.9

105

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 1.170 7.9 1.175 8.0 1.180 8.0 1.185 8.0 1.190 8.1 1.195 8.1 1.200 8.1 1.205 8.2 1.210 8.3 1.215 8.3 1.220 8.4 1.225 8.6 1.230 8.6 1.235 8.8 1.240 8.9 1.245 8.9 1.250 8.9 1.255 8.9 1.260 8.7 1.265 8.5 1.270 8.5 1.275 8.3 1.280 8.3 1.285 8.3 1.290 8.3 1.295 8.4 1.300 8.5 1.305 8.6 1.310 8.6 1.315 8.7 1.320 8.8 1.325 8.9 1.330 8.9 1.335 9.0 1.340 9.0 1.345 9.0 1.350 9.1 1.355 9.0 1.360 9.0

106

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 1.365 9.0 1.370 8.9 1.375 8.9 1.380 8.9 1.385 9.0 1.390 8.9 1.395 9.1 1.400 9.1 1.405 9.1 1.410 9.1 1.415 9.1 1.420 9.0 1.425 9.1 1.430 9.1 1.435 9.0 1.440 9.0 1.445 9.1 1.450 9.1 1.455 9.2 1.460 9.4 1.465 9.6 1.470 9.8 1.475 10.1 1.480 10.4 1.485 10.8 1.490 11.1 1.495 11.4 1.500 11.6 1.505 11.7 1.510 11.9 1.515 11.9 1.520 11.8 1.525 11.8 1.530 11.8 1.535 11.7 1.540 11.6 1.545 11.4 1.550 11.3 1.555 11.1

107

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 1.560 10.9 1.565 10.8 1.570 10.0 1.575 10.6 1.580 10.6 1.585 10.6 1.590 10.5 1.595 10.5 1.600 10.6 1.605 10.7 1.610 10.7 1.615 10.7 1.620 10.8 1.625 11.0 1.630 11.0 1.635 11.1 1.640 11.2 1.645 11.4 1.650 11.6 1.655 12.0 1.660 12.4 1.665 12.7 1.670 12.7 1.675 12.7 1.680 12.5 1.685 12.0 1.690 11.4 1.695 10.9 1.700 10.4 1.705 9.9 1.710 9.7 1.715 9.4 1.720 9.2 1.725 9.0 1.730 8.9 1.735 8.8 1.740 8.8 1.745 8.8 1.750 11.0

108

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 1.755 10.8 1.760 10.2 1.765 9.6 1.770 8.8 1.775 8.3 1.780 7.7 1.785 7.3 1.790 6.9 1.795 6.7 1.800 6.5 1.805 6.5 1.810 6.5 1.815 6.5 1.820 6.6 1.825 6.7 1.830 6.8 1.835 6.9 1.840 7.0 1.845 7.2 1.850 7.2 1.855 7.5 1.860 7.7 1.865 7.9 1.870 8.1 1.875 8.4 1.880 8.8 1.885 9.0 1.890 9.3 1.895 9.6 1.900 9.9 1.905 10.0 1.910 10.1 1.915 10.2 1.920 10.2 1.925 10.1 1.930 10.0 1.935 9.9 1.940 9.8 1.945 9.5

109

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 1.950 9.4 1.955 9.3 1.960 9.2 1.965 9.1 1.970 9.1 1.975 8.9 1.980 8.9 1.985 8.8 1.990 8.7 1.995 8.6 2.000 8.6 2.005 8.4 2.010 8.4 2.015 8.3 2.020 8.3 2.025 8.2 2.030 8.2 2.035 8.0 2.040 7.9 2.045 7.8 2.050 7.8 2.055 7.7 2.060 7.5 2.065 7.4 2.070 7.0 2.075 7.2 2.080 7.0 2.085 6.8 2.090 6.6 2.095 6.4 2.100 6.1 2.105 6.0 2.110 5.9 2.115 5.7 2.120 5.7 2.125 5.8 2.130 5.8 2.135 5.8 2.140 5.8

110

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 2.145 5.9 2.150 5.9 2.155 5.9 2.160 6.0 2.165 6.1 2.170 6.2 2.175 6.3 2.180 6.4 2.185 6.5 2.190 6.7 2.195 6.8 2.200 7.1 2.205 7.1 2.210 7.3 2.215 7.5 2.250 7.7 2.255 7.9 2.260 8.0 2.265 8.1 2.270 8.2 2.275 8.2 2.280 8.1 2.285 8.1 2.290 8.0 2.295 7.9 2.300 7.8 2.305 7.6 2.310 7.5 2.315 7.5 2.320 7.5 2.325 7.7 2.330 7.8 2.335 8.0 2.340 8.1 2.345 8.3 2.350 8.5 2.355 8.7 2.360 8.9 2.365 9.0

111

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 2.370 9.1 2.375 9.1 2.380 9.0 2.385 8.9 2.390 8.7 2.395 8.6 2.400 8.4 2.405 8.2 2.410 8.2 2.415 8.1 2.420 8.1 2.425 8.1 2.430 8.0 2.435 7.9 2.440 7.9 2.445 7.7 2.450 7.7 2.455 7.6 2.460 7.5 2.465 7.5 2.470 7.4 2.475 7.3 2.480 7.5 2.485 7.5 2.490 7.6 2.495 7.7 2.500 7.9 2.505 8.2 2.510 8.4 2.515 8.6 2.520 8.8 2.525 8.8 2.530 8.8 2.535 8.8 2.540 8.6 2.545 8.5 2.550 8.4 2.555 8.3 2.560 8.2

112

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 2.565 8.1 2.570 8.1 2.575 8.0 2.580 8.1 2.585 8.2 2.590 8.3 2.595 8.4 2.600 8.6 2.605 8.8 2.610 9.0 2.615 9.1 2.620 9.2 2.625 9.2 2.630 9.1 2.635 9.0 2.640 8.8 2.645 8.5 2.650 8.3 2.655 8.1 2.660 7.8 2.665 7.6 2.670 7.2 2.675 7.0 2.680 6.8 2.685 6.6 2.690 6.4 2.695 6.3 2.700 6.2 2.705 6.2 2.710 6.1 2.715 6.1 2.720 5.8 2.725 5.8 2.730 5.8 2.735 5.8 2.740 5.9 2.745 5.8 2.750 6.0 2.755 6.0

113

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 2.760 6.1 2.765 6.2 2.770 6.2 2.775 6.3 2.780 6.5 2.785 6.6 2.790 6.7 2.795 6.8 2.800 6.9 2.805 6.9 2.810 7.0 2.815 6.9 2.820 6.9 2.825 6.9 2.830 6.9 2.835 6.9 2.840 7.0 2.845 7.2 2.850 7.3 2.855 7.5 2.860 7.8 2.865 7.9 2.870 8.1 2.875 8.4 2.880 8.5 2.885 8.8 2.890 9.1 2.895 9.5 2.900 9.9 2.905 10.3 2.910 10.9 2.915 11.4 2.920 12.0 2.925 12.6 2.930 13.3 2.935 14.0 2.940 14.6 2.945 15.2 2.950 15.6

114

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 2.955 15.7 2.960 15.6 2.965 15.1 2.970 14.5 2.975 13.6 2.980 12.8 2.985 12.0 2.990 11.2 2.995 10.6 3.000 10.1 3.005 9.7 3.010 9.4 3.015 9.2 3.020 9.2 3.025 9.3 3.030 9.5 3.035 9.6 3.040 9.9 3.045 10.0 3.050 10.0 3.055 9.9 3.060 9.8 3.065 9.6 3.070 9.4 3.075 9.2 3.080 9.0 3.085 8.9 3.090 8.7 3.095 8.8 3.100 8.7 3.105 8.7 3.110 8.7 3.115 8.7 3.120 8.7 3.125 8.6 3.130 8.7 3.135 8.7 3.140 8.8 3.145 8.9

115

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 3.150 9.0 3.155 9.2 3.160 9.6 3.165 10.1 3.170 10.6 3.175 11.3 3.180 12.0 3.185 13.0 3.190 13.8 3.195 14.8 3.200 15.7 3.205 16.4 3.210 16.9 3.215 17.3 3.220 17.5 3.225 17.6 3.230 17.6 3.235 17.6 3.240 17.5 3.245 17.4 3.250 17.3 3.255 17.2 3.260 17.1 3.265 16.8 3.270 16.4 3.275 15.7 3.280 14.9 3.285 13.8 3.290 12.7 3.295 11.5 3.300 10.6 3.305 9.9 3.310 9.5 3.315 9.1 3.320 9.0 3.325 9.0 3.330 9.0 3.335 9.1 3.340 9.3

116

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 3.345 9.6 3.350 9.9 3.355 10.2 3.360 10.5 3.365 10.8 3.370 11.2 3.375 11.7 3.380 12.5 3.385 13.3 3.390 14.2 3.395 14.8 3.400 15.3 3.405 15.6 3.410 15.7 3.415 15.7 3.420 15.4 3.425 15.0 3.430 14.6 3.435 14.1 3.440 13.7 3.445 13.3 3.450 12.9 3.455 12.5 3.460 12.2 3.465 11.9 3.470 11.7 3.475 11.4 3.480 11.2 3.485 11.1 3.490 10.9 3.495 10.8 3.500 10.7 3.505 10.7 3.510 10.7 3.515 10.7 3.520 10.7 3.525 10.6 3.530 10.6 3.535 10.6

117

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 3.540 10.5 3.545 10.4 3.550 10.3 3.555 10.2 3.560 10.1 3.565 10.0 3.570 9.9 3.575 9.9 3.580 9.9 3.585 9.7 3.590 9.8 3.595 9.8 3.600 9.8 3.605 9.9 3.610 9.8 3.615 9.9 3.620 10.0 3.625 10.1 3.630 10.1 3.635 10.3 3.640 10.4 3.645 10.5 3.650 10.5 3.655 10.7 3.660 10.8 3.665 10.9 3.670 10.9 3.675 11.1 3.680 11.2 3.685 11.3 3.690 11.4 3.695 11.5 3.700 11.6 3.705 11.6 3.710 11.7 3.715 11.7 3.720 11.8 3.725 11.9 3.730 12.0

118

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 3.735 12.1 3.740 12.1 3.745 12.1 3.750 12.0 3.755 11.8 3.760 11.7 3.765 11.5 3.770 11.4 3.775 11.3 3.780 11.3 3.785 11.2 3.790 11.1 3.795 11.1 3.800 11.1 3.805 11.1 3.810 11.1 3.815 11.0 3.820 10.9 3.825 10.8 3.830 10.7 3.835 10.6 3.840 10.5 3.845 10.4 3.850 10.3 3.855 10.4 3.860 10.3 3.865 10.3 3.870 10.4 3.875 10.4 3.880 10.4 3.885 10.4 3.890 10.4 3.895 10.5 3.900 10.6 3.905 10.7 3.910 10.9 3.915 11.1 3.920 11.3 3.925 11.7

119

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 3.930 12.0 3.935 12.4 3.940 12.9 3.945 13.3 3.950 13.6 3.955 14.0 3.960 14.2 3.965 14.4 3.970 14.6 3.975 14.9 3.980 15.0 3.985 15.2 3.990 15.4 3.995 15.5 4.000 15.7 4.005 15.9 4.010 16.0 4.015 16.1 4.020 16.2 4.025 16.2 4.030 16.4 4.035 16.8 4.040 17.3 4.045 18.2 4.050 19.2 4.055 20.5 4.060 21.9 4.065 23.5 4.070 24.9 4.075 26.1 4.080 27.0 4.085 27.5 4.090 27.4 4.095 26.7 4.100 25.5 4.105 24.1 4.110 22.4 4.115 20.8 4.120 19.3

120

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 4.125 17.9 4.130 16.7 4.135 15.7 4.140 14.9 4.145 14.2 4.150 13.7 4.155 13.3 4.160 12.9 4.165 12.6 4.170 12.3 4.175 12.0 4.180 11.8 4.185 11.7 4.190 11.6 4.195 11.5 4.200 11.4 4.205 11.4 4.210 11.3 4.215 11.3 4.220 11.2 4.225 11.1 4.230 11.1 4.235 11.0 4.240 10.9 4.250 10.9 4.255 10.8 4.260 10.7 4.265 10.6 4.270 10.5 4.275 10.4 4.280 10.3 4.285 10.3 4.290 10.4 4.295 10.6 4.300 10.8 4.305 10.9 4.310 11.0 4.315 11.1 4.320 11.1

121

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 4.325 11.2 4.330 11.2 4.335 11.3 4.340 11.3 4.345 11.3 4.350 11.4 4.355 11.4 4.360 11.4 4.365 11.5 4.370 11.5 4.375 11.5 4.380 11.6 4.385 11.6 4.390 11.7 4.395 11.7 4.400 11.7 4.405 11.7 4.410 11.7 4.415 11.7 4.420 11.7 4.425 11.6 4.430 11.6 4.435 11.6 4.440 11.6 4.445 11.6 4.450 11.6 4.455 11.6 4.460 11.7 4.465 11.7 4.470 11.8 4.475 11.7 4.480 11.9 4.485 11.9 4.490 12.0 4.495 12.0 4.500 12.2 4.505 12.3 4.510 12.3 4.515 12.4

122

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 4.520 12.4 4.525 12.5 4.530 12.5 4.535 12.6 4.540 12.7 4.545 12.7 4.550 12.7 4.555 12.8 4.560 12.8 4.565 12.8 4.570 12.7 4.575 12.7 4.580 12.6 4.585 12.6 4.590 12.5 4.595 12.4 4.600 12.4 4.605 12.4 4.610 12.3 4.615 12.2 4.620 12.2 4.625 12.1 4.630 12.1 4.635 12.1 4.640 12.1 4.645 12.2 4.650 12.2 4.655 12.3 4.660 12.4 4.665 12.5 4.670 12.5 4.675 12.6 4.680 12.7 4.685 12.9 4.690 13.1 4.695 13.3 4.700 13.5 4.705 13.8 4.710 14.1

123

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 4.715 14.4 4.720 14.6 4.725 14.9 4.730 15.2 4.735 15.4 4.740 15.6 4.745 15.8 4.750 15.9 4.755 16.0 4.760 16.1 4.765 16.1 4.770 16.1 4.775 16.0 4.780 15.9 4.785 15.8 4.790 15.6 4.795 15.4 4.800 15.3 4.805 15.2 4.810 15.0 4.815 14.9 4.820 14.8 4.825 14.6 4.830 14.5 4.835 14.4 4.840 14.2 4.845 14.1 4.850 13.9 4.855 13.8 4.860 13.6 4.865 13.5 4.870 13.4 4.875 13.2 4.880 13.1 4.885 12.9 4.890 12.8 4.895 12.8 4.900 12.7 4.905 12.6

124

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 4.910 12.6 4.915 12.6 4.920 12.5 4.925 12.5 4.930 12.5 4.935 12.6 4.940 12.6 4.945 12.6 4.950 12.6 4.955 12.6 4.960 12.7 4.965 12.6 4.970 12.7 4.975 12.6 4.980 12.7 4.985 12.6 4.990 12.7 4.995 12.7 5.000 12.7 5.005 12.6 5.010 12.5 5.015 12.5 5.020 12.5 5.025 12.4 5.030 12.4 5.035 12.4 5.040 12.4 5.045 12.4 5.050 12.4 5.055 12.4 5.060 12.3 5.065 12.5 5.070 12.5 5.075 12.7 5.080 12.8 5.085 13.1 5.090 13.4 5.095 13.7 5.100 14.1

125

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 5.105 14.4 5.110 14.9 5.250 15.2 5.255 15.5 5.260 15.7 5.265 15.8 5.270 15.8 5.275 15.7 5.280 15.6 5.285 15.4 5.290 15.2 5.295 15.2 5.300 15.3 5.305 15.5 5.310 15.6 5.315 15.8 5.320 15.8 5.325 16.0 5.330 16.0 5.335 16.0 5.340 16.0 5.345 15.9 5.350 15.9 5.355 15.8 5.360 15.8 5.365 15.8 5.370 15.9 5.375 16.0 5.380 16.1 5.385 16.2 5.390 16.4 5.395 16.3 5.400 16.1 5.405 15.9 5.410 15.6 5.415 15.2 5.420 14.8 5.425 14.3 5.430 14.0

126

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 5.435 13.5 5.440 13.3 5.445 13.0 5.450 12.8 5.455 12.5 5.460 12.2 5.465 12.1 5.470 12.1 5.475 12.4 5.480 12.7 5.485 13.3 5.490 13.8 5.495 14.1 5.500 14.5 5.505 14.8 5.510 15.0 5.515 15.1 5.520 15.3 5.525 15.4 5.530 15.5 5.535 15.5 5.540 15.7 5.545 15.8 5.550 15.8 5.555 15.9 5.560 16.0 5.565 16.1 5.570 16.3 5.575 16.6 5.580 16.7 5.585 17.0 5.590 17.2 5.595 17.4 5.600 17.6 5.605 17.7 5.610 17.6 5.615 17.5 5.620 17.5 5.625 17.3

127

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 5.630 17.0 5.635 17.0 5.640 16.9 5.645 16.8 5.650 16.7 5.655 16.8 5.660 16.8 5.665 16.8 5.670 16.9 5.675 17.0 5.680 17.1 5.685 17.3 5.690 17.4 5.695 17.4 5.700 17.5 5.705 17.6 5.710 17.5 5.715 17.4 5.720 17.2 5.725 17.0 5.730 16.7 5.735 16.4 5.740 16.0 5.745 15.7 5.750 15.5 5.755 15.2 5.760 15.1 5.765 15.0 5.770 15.1 5.775 15.1 5.780 15.1 5.785 15.3 5.790 15.6 5.795 15.8 5.800 16.2 5.805 16.6 5.810 17.0 5.815 17.4 5.820 17.6

128

Table A-7. Continued Depth (mblf) Magnetic Susceptibility 5.825 17.8 5.830 17.7 5.835 17.6 5.840 17.4 5.845 17.2 5.850 17.0 5.855 16.9 5.860 16.7 5.865 16.6 5.870 16.4 5.875 16.3 5.880 16.2 5.885 16.0 5.890 15.9 5.895 15.7 5.900 15.4 5.905 15.1 5.910 14.7 5.915 14.4 5.920 14.1 5.925 13.8 5.930 13.6 5.935 13.5 5.940 13.2 5.945 13.0 5.950 12.9 5.955 12.9 5.960 13.0 5.965 13.3 5.970 13.8 5.975 14.4 5.980 15.0 5.985 15.6 5.990 16.1 5.995 16.6 6.000 17.0 6.005 17.1 6.010 17.2 6.015 17.2

129

Table A-8. Continued Depth (mblf) Magnetic Susceptibility 6.020 17.2 6.025 17.3 6.030 17.4 6.035 17.5 6.040 17.8 6.045 18.2 6.050 18.7 6.055 19.1 6.060 19.5 6.065 19.6 6.070 19.5 6.075 19.1 6.080 18.4 6.085 17.5 6.090 16.7 6.095 16.2 6.100 15.8 6.105 15.5 6.110 15.5 6.115 15.4 6.120 15.4 6.125 15.5 6.130 15.6 6.135 15.9 6.140 16.2 6.145 16.7 6.150 17.2 6.155 17.6 6.160 17.8 6.165 17.8 6.170 17.6 6.175 17.2 6.180 16.8 6.185 16.1 6.190 15.5 6.195 14.8 6.200 14.0 6.205 13.3 6.210 12.8

130

Table A-7. Continued 6.215 12.5 6.220 12.4 6.225 12.6 6.230 13.0 6.235 13.6 6.240 14.1 6.245 14.5

131

Table A-8. Scanning XRF data from core TS-18-XII-03. The unit for all elemental abundances is counts. Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

0.01 1093 8582 430 944 7413 1603 4752 1325 54848 690 552 1069 1238 0.02 1154 9118 322 1041 7063 1686 4875 1812 53592 792 536 1266 1149 0.03 1520 12366 413 874 8783 2043 5163 1852 56075 893 516 1194 1110 0.04 1510 12138 368 928 8737 1968 5235 1949 57152 799 571 1183 1251 0.05 1732 13083 366 764 9088 2077 5179 1994 58242 771 478 1176 1266 0.06 1773 13557 392 740 9780 2338 5834 2126 60190 950 607 1243 1170 0.07 1795 13828 295 752 10015 2409 5370 1986 61080 887 610 1272 1306 0.08 1816 14462 364 1031 10229 2433 6076 2870 63445 932 629 1422 1461 0.09 2058 16147 386 1192 10858 2568 6281 2585 64196 951 657 1387 1475 0.10 2180 17716 392 1046 11331 2850 6444 1926 65632 910 605 1359 1437 0.11 2146 17876 298 727 11364 2917 6555 2121 65933 1065 765 1458 1707 0.12 1941 15927 465 855 11045 2843 6104 2439 62546 948 686 1343 1555 0.13 1970 15553 342 914 11295 2541 5976 2188 62765 973 666 1391 1380 0.14 2576 18838 356 650 13452 2429 5962 876 63768 1050 651 1284 1555 0.15 2119 16065 380 743 11830 2592 5697 713 60126 1057 757 1406 1448 0.16 2624 19184 477 575 13057 2847 6365 585 64775 997 792 1257 1380 0.17 2488 18169 338 819 13495 2726 6296 790 64100 1033 684 1398 1664 0.18 2098 15729 395 658 11557 2960 6233 1311 64476 993 737 1309 1556 0.19 1703 13746 385 759 10154 3008 5585 4641 59615 913 634 1353 1586 0.20 2302 15864 384 515 11533 2916 6209 678 62846 932 766 1284 1272 0.21 2261 16010 495 840 11636 2755 6125 973 64194 1015 689 1358 1712 0.22 1941 14799 391 641 10986 2746 6020 1535 64445 964 652 1268 1530 0.23 2031 14389 551 677 11213 2879 5818 1148 66740 946 656 1183 1737 0.24 2091 14291 400 570 11180 3087 6009 969 63967 989 596 1346 1645 0.25 2382 16184 375 733 11571 3287 6279 786 64450 967 662 1403 1498 0.26 1868 14033 286 889 10888 3047 5982 1893 63270 901 632 1335 1990 0.27 1829 14241 398 682 9878 3395 5745 5505 62650 865 674 1223 1642

132

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

0.28 1989 16295 411 861 10941 3545 6372 1470 66905 962 654 1382 1524 0.29 1969 15048 310 814 11147 3587 6381 1201 67436 937 658 1271 1566 0.30 1837 14474 386 861 10936 3587 6576 3123 67370 1008 579 1436 1452 0.31 1327 10397 318 638 7992 2819 5535 1203 57181 842 474 1366 1496 0.32 1683 12259 449 1055 8367 2758 5558 1563 59215 753 505 1167 1227 0.33 2214 17456 452 724 10828 3419 7034 913 67139 887 659 1461 1453 0.34 2389 17770 381 882 11847 3683 6641 2012 67099 915 691 1444 1647 0.35 2388 18247 414 652 11813 3499 6388 1686 66348 895 683 1383 1258 0.36 2340 16472 357 810 11441 3189 6511 2656 65951 942 577 1351 1675 0.37 1852 14141 482 1007 10038 2943 6229 1689 66812 1001 681 1308 1350 0.38 1572 13022 391 512 9809 2705 6538 941 67578 995 644 1266 1431 0.39 2358 17292 391 506 11519 3094 6830 1015 67204 1061 737 1610 1310 0.40 2003 15325 479 537 10925 2903 6679 778 66662 972 810 1349 1338 0.41 1862 14851 500 699 10517 3080 6947 1371 65362 812 617 1353 1616 0.42 2179 16301 307 607 11068 2946 6696 1192 65684 917 661 1497 1335 0.43 2371 17782 341 898 11324 3177 7164 886 65708 920 716 1426 1495 0.44 1865 14867 436 1088 9938 2819 6938 764 65335 947 700 1413 1217 0.45 2027 15298 482 595 10071 3112 6520 1074 66395 891 655 1556 1232 0.46 2307 17456 341 726 10725 3451 6692 617 66399 844 648 1497 1386 0.47 2194 15771 462 828 9707 3090 5996 770 59954 895 584 1256 1354 0.48 2378 18070 498 875 11147 3480 6753 716 66979 860 635 1444 1241 0.49 2087 15685 414 785 10067 3538 6192 1092 64178 880 675 1375 1282 0.50 2309 17800 411 1013 10633 5042 6799 1184 66216 885 602 1356 1615 0.51 2204 17214 404 869 10483 3361 6682 1150 64363 946 740 1431 1515 0.52 2413 18648 321 658 10930 3728 6730 1251 67366 906 620 1492 1382 0.53 1792 13428 389 970 7735 7896 5372 1219 54351 703 674 991 1152 0.54 2716 19680 268 747 11432 5846 7034 1339 71003 832 661 1470 1318 0.55 1578 12896 411 784 7941 6259 5310 1341 55248 693 673 1138 1351

133

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

0.56 1640 13198 478 899 8144 12735 5886 1293 58658 764 866 1157 939 0.57 2494 18344 306 1195 9960 22028 6643 1280 66341 827 769 1298 1185 0.58 2602 19977 452 869 11668 4972 7641 1549 71964 988 705 1496 1426 0.59 2401 18186 408 933 11035 4039 7414 2031 67899 1122 752 1432 1682 0.60 2430 18375 359 838 10850 4126 7326 1544 69921 893 705 1439 1244 0.61 2216 18102 297 962 10220 3845 7339 1453 67709 911 615 1498 819 0.63 2734 19698 361 959 11058 3328 7353 1517 70931 974 571 1506 1318 0.64 2419 19429 504 559 10994 3267 7609 1731 69627 801 628 1519 1359 0.65 2411 19384 501 672 10872 3077 7221 1806 67831 818 606 1379 1378 0.66 2593 20048 392 722 11377 3279 7636 1613 68630 869 561 1485 1360 0.67 2459 19407 619 781 10955 2882 6885 1471 65948 879 702 1668 1472 0.68 2638 20318 533 937 10971 3050 7374 1624 69356 901 651 1378 1207 0.69 2506 19170 409 744 10987 3102 7526 1553 71131 914 613 1566 1279 0.70 2565 19551 365 572 10870 3256 7347 1624 70560 804 638 1462 1257 0.71 2530 18763 438 474 10651 3147 7522 1683 70515 859 596 1508 1163 0.72 2434 18672 407 901 10201 3271 7095 1667 69493 819 603 1497 961 0.73 2355 18577 440 804 9651 3070 7783 1789 70088 796 619 1386 1135 0.74 2587 19813 433 730 10055 3431 8202 2185 72988 815 617 1572 1034 0.75 2145 16728 478 382 8894 2937 7167 1853 68155 779 538 1379 1410 0.76 2033 16320 446 925 8737 3141 7372 1944 70420 690 601 1620 1311 0.77 2192 17963 544 630 9177 3195 7744 2131 71471 847 586 1558 1184 0.78 1988 16449 506 633 8677 2868 7465 1915 70835 751 546 1461 1107 0.79 2157 19448 411 959 9213 2942 8353 1914 70501 755 620 1709 1406 0.80 2178 18822 369 539 8850 2799 8287 1886 68929 740 596 1665 1141 0.81 2156 17580 343 663 9129 3160 7525 1851 69369 795 568 1682 1242 0.82 2184 20073 442 823 8514 3013 9102 2318 79003 544 521 1687 1332 0.83 1966 18675 493 566 7920 2755 8976 2100 69261 670 637 1763 1310 0.84 1886 18556 498 972 7591 2735 9523 1904 70649 683 568 2025 1098

134

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

0.85 1892 18525 524 697 7354 2792 9640 1705 66549 742 532 1984 1195 0.86 2036 16003 461 785 8148 2961 7527 1491 63256 737 636 1444 1038 0.87 2152 17834 568 591 6934 2849 8441 1293 63640 634 509 1590 962 0.88 2447 18163 530 709 6888 2870 7990 1196 62404 726 394 1735 888 0.89 1780 13559 587 786 5874 2686 7756 1097 60098 577 436 1701 841 0.90 1658 11013 577 493 3935 2493 6186 1114 55050 718 404 1635 891 0.91 1591 12346 577 311 4395 2552 7198 966 54549 591 353 1722 904 0.92 2059 12423 685 686 4222 2647 5446 854 54874 720 444 1750 883 0.93 1922 13128 668 565 4635 2682 5995 895 55309 589 385 1615 842 0.94 1744 11491 677 866 4234 2701 5636 1017 53501 619 369 1517 948 0.95 1550 11101 756 529 3713 2457 5223 857 51258 602 332 1622 851 0.96 1385 9405 532 603 3528 2384 5033 673 51471 663 373 1631 826 0.97 1362 10074 634 597 4472 2375 5989 952 51732 688 451 1769 771 0.98 1728 11274 670 645 3797 2398 5082 816 50923 641 351 1647 769 0.99 1702 11340 659 672 3669 2426 5250 741 49835 642 312 1624 805 1.00 1804 11532 794 764 4117 2514 5253 765 49264 551 280 1811 655 1.01 1628 10412 755 676 3533 2470 4957 521 48496 702 402 1561 639 1.02 1623 11145 683 619 3978 2556 5107 693 50201 763 306 1829 747 1.03 1347 8867 748 586 2915 2074 4083 585 40072 669 363 1608 815 1.04 1454 9773 719 462 3888 2476 5007 659 47076 668 364 1772 846 1.05 852 6039 700 687 2924 2062 4322 695 39040 634 337 1495 742 1.06 875 6415 686 286 2455 1887 3878 627 36072 590 317 1460 742 1.07 1045 7312 725 560 3004 1988 4416 465 41071 507 319 1350 713 1.08 1847 11665 716 822 4044 2324 5126 661 44200 580 314 1597 889 1.09 743 5474 688 650 2974 2057 4565 668 41397 582 281 1532 676 1.10 489 4164 718 358 2179 1525 3746 400 31480 517 275 1318 588 1.11 437 3146 626 111 1512 1323 2854 450 23718 387 215 1091 554 1.12 746 5372 662 437 2201 1759 3724 562 31578 436 259 1233 675

135

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

1.13 1087 8203 784 376 3050 1987 4261 763 37240 563 300 1407 593 1.14 1071 7157 722 282 2753 2014 4179 682 35775 541 198 1303 631 1.15 987 6866 777 448 2817 1920 4229 649 36137 595 275 1476 669 1.16 1386 9294 877 472 3624 2257 4890 925 42467 669 278 1474 694 1.17 1804 11262 942 507 4303 2622 5583 620 47633 724 378 1518 938 1.18 1710 11220 842 331 4192 2501 5570 802 46974 663 371 1619 1081 1.19 1363 9521 968 590 3994 2282 4942 614 46816 655 319 1578 822 1.20 1279 8652 976 586 3816 2321 5317 653 44931 693 321 1717 801 1.21 1387 9295 1085 761 3953 2243 5298 619 43289 767 374 1746 783 1.22 1653 11043 978 896 4147 2038 5515 801 44293 775 398 1816 835 1.23 1433 10239 1047 556 4079 2246 5350 702 44606 691 334 1692 891 1.24 1481 9974 1012 976 3980 2101 5263 578 44499 659 331 1714 794 1.25 1471 10363 1087 666 3922 2234 5457 713 45830 647 402 1767 798 1.26 1311 9641 1180 396 3606 2184 5201 601 45627 634 364 1732 778 1.27 1567 10705 1098 599 3862 2029 5421 601 47152 630 406 1776 806 1.28 1544 10705 1150 892 3999 2142 5524 442 47012 688 327 1843 858 1.29 1516 10604 1156 581 3829 2205 5374 615 46143 575 303 1712 895 1.30 1665 11305 1193 826 3828 2292 5617 757 46232 624 314 1866 692 1.31 1347 9503 834 764 3355 2098 4984 468 42332 622 314 1685 925 1.32 1772 11882 1178 936 4110 2303 5599 499 46837 642 378 1876 773 1.33 1563 10712 1035 753 3658 2287 5424 671 44199 594 266 2057 709 1.34 1583 10902 1152 754 3635 2121 5510 637 47500 595 362 1798 843 1.35 1741 12036 1048 572 4014 2342 5819 569 45529 636 400 1961 888 1.36 1670 11458 1072 755 3908 2292 5984 419 45149 563 406 2024 612 1.37 1812 12556 1120 703 4247 2182 6256 785 45779 645 366 2043 707 1.38 1728 12792 845 854 3993 2287 6169 570 45732 582 429 2075 949 1.39 1816 12087 1012 846 3852 2213 5927 528 45096 656 417 2036 813 1.40 1690 11774 863 682 3743 2275 5842 640 43309 586 277 1868 801

136

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

1.41 1893 13024 962 859 4094 2324 6321 564 46296 574 369 2073 828 1.42 1982 12937 813 735 4046 2224 6193 600 46002 604 376 1897 981 1.43 2052 14121 820 719 3804 2331 6122 648 46440 647 376 2304 922 1.44 2064 14426 847 572 3837 2432 6748 673 46560 639 503 2280 701 1.45 2077 15108 737 494 3631 2196 7186 759 44349 637 367 2272 779 1.46 2119 16139 878 679 3659 2550 7382 535 45368 598 492 2527 1017 1.47 2178 16262 763 694 3639 2436 7831 586 46641 579 383 2539 892 1.48 2111 15557 760 844 3802 2340 7409 694 45977 621 450 2480 772 1.49 2381 17140 782 570 3980 2536 7338 647 46447 573 380 2486 730 1.50 2101 15151 764 770 3954 2386 7308 548 45264 661 375 2422 697 1.51 2018 14244 689 907 3739 2333 7211 468 45031 617 335 2141 1108 1.52 2120 14905 686 797 3837 2328 6863 624 45109 471 271 2261 866 1.53 2095 14301 718 913 3806 2540 6742 623 45996 676 386 2030 878 1.54 2065 14017 699 859 3780 2445 6478 582 44380 660 403 2127 649 1.55 2139 14995 751 861 3927 2510 6782 601 44838 538 408 1923 870 1.56 2113 14552 671 807 4067 2469 6806 482 45859 563 340 2167 735 1.57 2021 13927 615 518 3758 2433 6843 501 44186 616 305 1966 751 1.58 1790 13736 789 795 3689 2408 6689 500 43700 582 347 2212 962 1.59 1715 13552 722 360 3814 2407 6506 634 43206 491 290 2051 843 1.60 1715 12633 841 523 3761 2369 6328 561 44354 629 303 2044 1019 1.61 1966 13437 866 767 3911 2470 6569 573 45434 600 369 1935 817 1.62 2016 13148 888 714 3744 2425 6238 672 47119 612 361 1795 651 1.63 1652 11133 673 668 3592 2480 5872 764 48099 622 366 1830 725 1.64 1915 12894 689 765 3894 2488 5831 704 47328 669 299 1940 935 1.65 2034 13168 734 785 4078 2421 6078 522 47974 656 363 1810 839 1.66 2056 13661 778 644 4083 2467 5894 478 49322 669 305 1727 894 1.67 1796 12415 701 707 3864 2448 6021 553 49610 720 409 1649 766

137

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

1.68 1285 8792 772 642 3496 2165 5384 501 47962 711 397 1563 667 1.69 1399 9991 709 509 3540 2091 5572 676 48416 717 434 1545 721 1.70 2030 13057 869 815 4409 2368 5748 527 49429 678 344 1688 590 1.71 1877 12598 791 574 4217 2376 5912 563 48698 719 308 1618 845 1.72 1814 12070 806 629 4063 2372 5802 470 48370 612 312 1705 771 1.73 1673 11974 756 762 4042 2329 5781 612 50344 762 339 1630 748 1.74 2012 13334 827 872 4127 2339 5829 438 49709 658 369 1579 735 1.75 2137 13984 810 789 4223 2324 5810 445 49767 695 374 1756 890 1.76 1859 12831 835 552 3732 2195 5866 513 52671 668 367 1713 799 1.77 1992 13177 761 719 3885 2203 6018 517 54011 608 289 1594 727 1.78 1792 11564 717 782 3693 2298 5885 555 52248 608 326 1615 819 1.79 2326 15082 659 460 4088 2487 6590 474 52196 595 345 1856 762 1.80 2453 16119 781 681 4154 2482 6337 578 51396 707 397 1821 858 1.81 2544 16205 712 716 4150 2606 6550 481 52434 618 329 1726 792 1.82 2520 16016 579 611 3927 2874 6493 508 53548 694 314 1834 871 1.83 2135 14045 700 729 3755 2770 6467 443 54897 671 498 2123 819 1.73 1987 12926 756 648 5215 2569 5168 876 48722 741 494 1706 1103 1.76 2192 15043 774 694 5273 2785 6331 777 52588 648 429 1667 928 1.77 2270 14569 639 617 4769 2656 6196 807 50347 587 303 1742 600 1.78 2232 14158 722 528 4425 2598 6230 772 50386 647 457 1592 823 1.79 1884 11974 684 797 4176 2332 6168 718 51217 691 298 1723 726 1.80 1933 12984 861 634 3813 2231 5882 530 51110 660 314 1645 753 1.81 1995 12625 866 659 3837 2227 6043 641 48552 565 241 1507 843 1.82 2280 14787 648 773 4054 2216 6271 610 50555 621 389 1667 661 1.84 1814 11942 702 499 3259 1883 5242 549 45796 519 333 1634 789 1.85 2196 13909 704 675 3814 2356 6125 370 52939 679 399 1814 716 1.86 2098 13729 792 653 3895 2403 6355 453 52537 611 265 1789 765

138

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

1.87 2162 14239 673 808 3864 2514 6562 478 52690 604 406 1769 793 1.88 1810 11813 657 591 3678 2333 6097 400 51789 747 340 1817 778 1.89 1851 13002 666 314 3634 2099 6196 306 49413 675 458 1865 836 1.90 2108 14177 809 835 3851 2384 6748 545 52017 621 360 1814 919 1.91 1931 13183 726 526 3745 2340 6614 476 52769 692 355 1842 805 1.92 2071 13487 684 598 3901 2213 6380 383 52473 638 319 1829 583 1.93 1774 12772 725 601 3584 2216 6525 597 52211 661 322 1943 734 1.94 1854 12518 734 472 3351 2176 6122 487 52020 557 283 1813 807 1.95 2115 14252 756 714 3703 2334 6344 483 54439 546 328 1960 962 1.96 2409 15081 753 777 3709 2280 6727 552 56073 651 452 1810 886 1.97 2315 14994 575 533 3714 2325 6581 413 55321 630 349 1795 676 1.98 2178 13960 676 435 3682 2127 6732 347 55378 491 319 1868 626 1.99 2269 14992 686 613 3854 2349 6903 537 55526 582 350 1765 769 2.00 2164 13982 766 717 3678 2324 6550 636 54557 620 322 2011 924 2.01 2108 13786 635 233 3351 2210 6278 644 51711 616 287 1636 640 2.02 1669 11401 618 423 3081 2095 6104 535 53637 582 329 1750 737 2.03 1953 12465 694 447 3461 2121 6388 516 54678 544 321 1836 967 2.04 1705 11414 646 416 3327 2240 6081 628 54013 596 360 1743 795 2.05 1636 10765 760 433 2900 2177 6153 712 52645 578 313 1854 648 2.06 1611 10915 636 473 2976 2167 6325 618 53320 607 305 1752 808 2.07 1304 9125 734 645 2667 2050 6259 454 51619 486 320 1795 664 2.08 1515 10477 710 645 2805 1914 6383 443 52921 552 383 1825 793 2.09 1697 11495 696 723 2985 2210 6704 639 53129 505 258 1976 683 2.10 2038 14073 500 444 3009 2198 7392 560 51896 533 281 2211 823 2.11 1983 13863 534 722 3147 2222 7390 672 53737 517 443 2024 817 2.12 2125 14719 645 875 3309 2274 7150 567 55232 549 319 2002 834 2.13 2081 14292 521 314 3049 2134 6929 711 54509 453 318 1861 636 2.14 2169 14426 631 682 3297 2267 7147 907 58674 566 307 1782 667

139

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

2.15 2065 14130 667 543 3144 2142 6691 726 57240 499 329 1865 898 2.16 2173 14183 700 593 3356 2404 7159 912 60037 529 259 1734 648 2.17 2198 14906 558 415 3305 2191 7357 1043 62805 444 332 1890 753 2.18 2096 13898 655 570 3198 2177 7089 1314 63869 450 296 1776 617 2.19 2112 14267 681 534 3249 2444 7167 1302 68091 417 322 1695 647 2.20 2071 14186 535 211 2999 2254 6943 1114 68157 382 275 1710 695 2.21 2039 14022 664 631 3021 2135 7172 1311 69897 533 319 1687 662 2.22 2470 15641 714 729 3355 2522 7465 1524 70060 431 245 1856 672 2.23 2485 16388 637 771 3285 2504 7610 1189 70257 430 338 1720 700 2.24 2267 14118 547 622 3069 2193 7580 1075 66348 466 302 1907 755 2.25 2468 16333 439 403 3127 2230 7672 1053 65612 412 348 1787 769 2.26 2310 15421 578 701 3211 2365 7439 848 61010 452 288 1828 750 2.27 2084 15382 621 733 2999 2181 7547 719 59682 530 297 1970 705 2.28 2215 15221 558 509 3064 2275 7659 579 57957 436 364 1875 845 2.29 2046 13511 606 734 2924 2258 7198 512 58368 510 357 1926 699 2.30 1796 12657 605 465 2952 2286 7174 721 57097 414 318 1753 734 2.31 1961 13319 489 718 2848 2227 7235 646 57680 448 279 1774 641 2.32 1884 13163 479 461 2989 2099 7492 564 58629 596 336 1955 744 2.33 2049 13449 540 466 2847 2146 7151 544 60377 507 355 1869 643 2.34 2484 16505 579 703 3304 2315 7681 674 59876 524 381 1881 677 2.35 2621 17319 464 739 3307 2377 8209 469 59600 591 435 2076 915 2.36 2602 17808 497 555 3521 2206 7967 626 62076 483 337 1943 787 2.37 2675 17909 619 777 3438 2283 7977 634 62193 445 356 2049 706 2.38 2695 18301 601 648 3430 2193 8327 614 61733 500 303 2064 891 2.39 1953 15606 672 772 3157 2124 8215 469 62570 562 338 2120 604 2.40 2279 16489 613 761 3454 2096 7946 517 57280 477 329 2186 599 2.41 2202 15801 638 612 3454 2001 8115 410 55730 505 262 1991 832 2.42 2719 19444 460 778 3674 2154 8596 481 57084 516 394 2393 677

140

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

2.43 2911 19866 548 815 3793 2221 8607 600 57162 538 292 2156 1070 2.44 2999 20593 523 589 3892 2399 9106 527 55541 574 355 2143 725 2.45 3134 21854 588 963 3855 2258 9376 532 57202 684 391 2374 789 2.46 2969 20854 430 529 3807 2044 9061 410 56015 578 355 2370 625 2.47 2429 18575 524 695 3524 2144 9023 523 51979 446 323 2164 867 2.48 2857 21376 478 489 3842 2113 9495 667 55501 578 366 2173 764 2.49 3059 21897 535 667 3715 2250 9799 849 54077 490 283 2462 620 2.50 3019 21353 535 460 3605 2147 9538 786 55744 517 312 2369 647 2.51 2874 21550 497 443 3537 2202 10070 786 57348 480 296 2469 605 2.52 2550 19498 486 568 3442 2259 9423 880 64942 417 411 2292 725 2.53 2756 20341 480 402 3580 2309 9226 1085 66647 493 332 2133 769 2.54 2841 20142 423 346 3348 2315 9155 1226 68626 403 342 2051 765 2.55 2767 19965 534 597 3463 2326 8730 1081 68992 474 383 2140 983 2.56 2892 20947 432 525 3550 2225 9855 1057 63871 420 307 2291 818 2.57 2356 18318 560 601 3391 2186 9184 1311 71293 564 501 2091 635 2.58 2764 21324 484 446 3585 2226 9994 1216 67919 424 247 2436 774 2.59 2673 23663 406 602 3596 2317 11138 1312 66015 419 395 2807 901 2.60 2792 22387 504 656 3295 2242 10508 1312 65801 470 358 2450 653 2.61 2604 22591 518 694 3336 2147 10548 1255 66116 344 332 2659 719 2.62 2777 24398 434 642 3539 2142 11583 1302 64509 443 338 2699 682 2.63 2160 18574 566 630 3083 1962 10530 1258 63165 372 319 2546 781 2.64 2843 23944 489 717 3453 1956 10922 928 60802 502 335 2693 696 2.65 2587 23416 607 295 3307 1993 11520 816 57923 365 374 2950 900 2.66 2810 24976 455 440 3363 2106 11556 985 57156 473 411 3132 781 2.67 2674 24336 403 539 3273 2035 11341 884 57405 469 315 2933 870 2.68 2645 23987 493 391 3219 2034 11143 729 56341 430 370 3312 856 2.69 2745 23173 476 321 3279 2076 10912 701 58345 440 326 2821 630 2.70 2085 19551 529 432 3058 1828 11220 704 52438 414 403 3182 764

141

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

2.76 2800 22701 423 495 3428 2124 9353 1022 61528 541 403 2344 774 2.77 2182 20681 408 953 3183 2141 11226 1042 69352 455 357 2840 728 2.78 2138 20143 493 584 2960 1832 10063 1036 58249 415 340 2946 724 2.79 2751 24458 440 734 3304 2000 10438 657 52249 405 350 2875 907 2.80 2573 24942 544 712 3178 1794 10981 693 51951 457 349 3350 903 2.81 2800 26969 560 640 3489 2097 11813 753 52334 435 439 3229 1005 2.82 2743 28672 481 756 3321 1986 12461 578 50588 425 440 3406 855 2.83 2685 27031 511 541 3123 1831 12523 637 51131 304 394 3211 840 2.84 2659 27240 495 413 3175 1839 12238 523 49670 436 431 3393 844 2.85 2530 26290 548 879 3158 1865 12515 635 50073 394 357 3237 794 2.86 2513 26016 391 577 3050 1774 12398 583 50320 447 302 3383 754 2.87 2533 27121 470 514 3234 1796 12291 601 49633 482 385 3609 781 2.88 2708 26562 461 725 3258 1782 12179 582 51979 395 344 3226 853 2.89 3020 25772 435 730 3404 1882 11785 484 55994 465 418 2968 980 2.90 2966 25480 410 597 3539 1886 11631 539 57927 384 420 2946 692 2.91 2994 24037 518 561 3539 1787 10647 670 60071 447 382 2648 807 2.92 2984 25236 465 935 3497 1863 10990 585 60848 466 369 2644 755 2.93 2869 23641 450 399 3313 1841 11026 560 59709 478 375 2868 620 2.94 2784 23629 483 447 3526 1897 10690 513 59661 462 312 2530 732 2.95 3005 24776 423 461 3682 1889 10989 500 59303 378 322 2792 705 2.96 3114 25454 520 435 3707 2086 11196 587 59757 479 350 2880 637 2.97 3073 25058 496 392 3558 1824 11082 428 57700 388 326 2769 753 2.98 2712 23053 606 579 3354 1853 11049 625 53033 472 320 2655 766 2.99 2666 24063 553 324 3417 1687 11289 509 52723 450 382 2971 742 3.00 2845 23589 529 531 3518 1710 11076 509 53188 440 355 2743 744 3.01 2852 23772 591 502 3530 1764 10954 389 55777 533 394 2566 673 3.02 2598 23208 539 491 3360 1653 11170 507 52517 432 395 2782 823 3.03 2716 24934 609 728 3308 1739 11765 528 52582 356 384 2839 716

142

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

3.04 2717 23935 501 413 3323 1832 11784 557 54905 489 300 2994 678 3.05 2474 22111 495 597 3330 1754 11138 365 54248 479 366 2654 667 3.06 2580 24296 662 629 3513 1701 12104 517 54641 473 350 2772 755 3.07 2892 25512 496 749 3467 1836 12086 501 54734 557 405 2832 771 3.08 2922 25725 603 583 3519 1765 12301 603 54650 396 324 2883 793 3.09 3101 26522 541 872 3605 1870 12104 512 55299 480 386 2843 955 3.10 2846 24637 436 506 3218 1646 12024 522 53249 468 446 2919 692 3.11 2543 24701 594 488 3204 1693 11852 505 51113 447 308 3004 906 3.12 2757 26047 415 346 3304 1675 12344 577 52786 463 310 2800 725 3.13 2678 24663 565 493 3308 1779 11933 410 52720 501 382 2888 818 3.14 2773 26305 513 487 3095 1679 11848 487 50633 402 344 3038 950 3.15 2761 26335 476 597 3430 1654 12532 394 52695 414 344 2918 656 3.16 2852 27311 434 533 3302 1748 12214 472 53159 497 364 2965 630 3.17 2348 21376 437 357 2897 1437 10993 456 49753 376 301 2539 769 3.18 2479 22225 586 281 2819 1516 11378 620 49680 396 321 2675 741 3.19 2339 22986 499 427 2968 1342 11550 606 48627 449 392 2916 758 3.20 2644 23377 449 480 3060 1641 11871 710 49966 361 420 2808 718 3.21 2739 23441 469 351 3091 1611 11509 477 52071 492 292 2643 797 3.22 2881 25366 526 476 3344 1653 11887 350 51265 427 384 2976 896 3.23 2689 24012 314 311 3113 1574 12282 523 52344 460 273 2815 915 3.24 2609 22252 406 410 3087 1593 11327 564 51862 370 334 2826 594 3.25 2565 23316 617 718 3077 1511 11599 480 53202 466 349 2780 616 3.26 2529 22872 414 313 3067 1563 11726 411 53580 391 377 2864 651 3.27 2866 25775 505 701 3404 1658 12121 424 54804 440 371 2747 717 3.28 2400 23743 578 519 3274 1572 11878 344 49111 489 383 3089 829 3.29 2638 24283 486 539 3334 1753 11967 332 51284 455 449 3154 768 3.30 2169 19813 574 590 2705 1377 10630 396 46922 447 374 2731 601 3.31 2487 23017 489 490 3251 1601 11582 408 54791 464 349 2887 825

143

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

3.32 2654 23143 488 555 3196 1659 11790 496 55299 565 477 2779 834 3.33 2692 23450 396 439 3350 1764 11574 513 56171 488 440 2600 696 3.34 3047 26053 507 867 3543 1912 12032 426 54242 440 350 2942 642 3.35 2723 23975 504 549 3417 1652 11958 460 54201 460 372 2835 714 3.36 2620 23100 546 262 3315 1724 11446 591 52450 430 418 2905 653 3.37 2680 23591 455 606 3339 1535 11471 487 52761 523 437 2822 738 3.38 2793 24660 477 553 3275 1832 11563 563 54010 395 336 2701 783 3.39 2774 24558 546 677 3530 1844 11496 571 54362 486 394 2795 721 3.40 2618 23510 438 867 3381 1611 11322 378 55670 496 401 2804 615 3.41 2881 25381 492 669 3530 1795 11761 360 57520 519 430 2522 633 3.42 3010 26567 509 675 3507 1732 12423 451 56320 464 411 2859 719 3.43 2680 25779 426 901 3329 1801 11877 334 55500 538 431 2955 900 3.44 2932 25760 440 818 3518 1907 12145 369 57493 475 378 2712 845 3.45 2870 26203 369 827 3348 1772 12141 425 59984 465 350 2577 704 3.46 2724 24589 451 821 3214 1685 11690 224 54652 485 395 2772 1046 3.47 2965 25208 512 625 3394 1693 12180 361 56620 463 347 2646 991 3.48 3072 26444 420 604 3446 1716 12210 565 59826 456 368 2769 762 3.49 2917 26431 430 891 3512 1788 12855 306 56034 500 413 2796 771 3.50 2783 26339 453 571 3501 1768 12220 416 55675 485 355 2750 739 3.51 2755 25318 342 754 3410 1717 12221 462 56329 441 364 2717 729 3.52 2658 25279 453 700 3396 1696 11973 403 57146 475 380 2656 577 3.53 2815 25534 440 634 3245 1631 12141 564 57623 528 436 2650 799 3.54 2788 26058 323 475 3154 1671 11760 490 59227 400 411 2797 715 3.55 2851 26168 435 516 3265 1694 11330 256 58261 391 348 2705 590 3.56 2933 26856 407 561 3209 1794 12089 496 57780 435 365 2562 770 3.57 2949 25842 516 581 3514 1654 11996 304 58537 460 372 2648 744 3.58 2951 27436 481 640 3318 1660 12473 428 57433 430 403 2812 734 3.59 3099 29462 444 641 3510 1626 12593 437 57342 448 322 2882 795

144

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

3.60 2912 27297 426 802 3310 1606 12047 332 58284 443 389 2801 665 3.61 2840 27226 550 585 3269 1773 12275 501 58373 424 444 2711 652 3.62 2837 26123 388 512 3262 1479 11751 397 57973 492 398 2639 746 3.63 2857 25101 439 325 3132 1561 11362 373 55929 471 389 2513 692 3.64 2843 27307 356 465 3424 1561 11665 411 56146 404 415 2642 567 3.65 2680 25137 424 195 3183 1540 10977 314 51257 390 306 2566 633 3.66 2811 26437 565 675 3110 1460 11360 304 55740 455 373 2521 801 3.67 2681 25621 411 551 3237 1510 10972 441 53878 428 295 2557 875 3.68 2778 26237 561 583 3138 1596 11550 564 54066 480 357 2663 789 3.69 2399 23421 481 520 2861 1453 10641 415 53176 432 412 2694 809 3.70 2776 24765 386 766 3248 1633 11266 517 52460 450 362 2610 765 3.71 2549 25118 474 721 2965 1499 11197 553 54236 486 438 2707 815 3.73 2679 23069 504 667 3332 1632 10577 474 52559 512 396 2527 704 3.74 2899 23775 499 663 3544 1671 10391 692 56331 479 370 2503 752 3.75 2761 23003 485 540 3402 1726 10224 452 57541 524 417 2431 802 3.76 2601 22657 586 587 3556 1644 10787 420 56671 498 379 2491 881 3.77 2691 25002 540 688 3455 1591 11906 444 53582 514 425 2650 852 3.78 3236 24513 409 343 3790 1673 10564 318 53403 482 352 2213 679 3.79 3247 27219 496 377 3643 1568 10642 521 49514 460 371 2439 680 3.80 3016 25054 515 901 3674 1541 10766 469 57349 417 368 2326 841 3.81 3037 25830 554 750 3808 1640 10985 524 57763 424 348 2456 855 3.82 2895 26109 533 655 3468 1614 11290 593 56593 409 464 2529 823 3.83 2888 24951 474 521 3572 1526 10872 497 59389 523 390 2323 583 3.84 2887 25233 511 415 3437 1720 11205 537 58525 400 324 2484 778 3.85 2772 25780 439 691 3488 1581 10742 871 62369 557 442 2360 708 3.86 2609 24033 463 474 3361 1566 10655 621 60964 383 346 2362 764 3.87 2712 23842 524 560 3463 1577 10668 473 60816 497 402 2390 823 3.88 2973 26125 486 433 3357 1615 11191 614 57987 491 395 2434 734

145

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

3.89 2981 26400 471 547 3688 1602 11339 602 56700 387 338 2635 736 3.90 2604 24824 562 546 3378 1647 11001 515 61465 480 318 2249 666 3.91 2561 23348 493 498 3434 1495 10742 424 61752 453 312 2318 637 3.92 2585 23590 451 365 3298 1470 10563 641 61500 419 407 2270 720 3.93 2465 22647 470 786 3183 1662 10432 530 65871 455 344 2171 741 3.94 2478 22881 547 494 3290 1536 10872 645 60401 509 385 2537 890 3.95 2247 23034 517 670 3330 1443 10694 718 58845 449 337 2402 807 3.96 2498 22453 525 666 3494 1614 10841 730 60432 523 546 2520 834 3.97 2552 23721 446 609 3402 1609 10750 871 59133 528 394 2433 834 3.98 2434 22717 513 476 3439 1543 10636 907 62028 450 289 2401 861 3.99 2527 22712 486 524 3364 1505 10466 721 60010 447 356 2438 934 4.00 2481 22966 485 570 3244 1666 10685 814 57978 455 424 2346 787 4.01 2207 20803 488 573 2909 1537 10425 844 60340 409 384 2199 708 4.02 2327 22118 461 511 3213 1511 10411 828 59943 371 351 2313 829 4.03 2447 21795 502 928 3208 1572 10492 1041 61738 369 325 2303 595 4.04 2193 21223 494 592 3135 1601 10323 1141 61190 415 365 2224 746 4.05 2394 22585 611 406 3422 1575 10532 997 59856 473 373 2380 784 4.06 2711 25720 435 680 3625 1614 10698 1098 60932 460 352 2298 910 4.07 2494 23833 467 490 3390 1519 10832 999 61543 526 394 2251 719 4.08 2680 23837 515 519 3407 1710 10567 1220 64341 495 325 2314 836 4.09 2547 23382 463 420 3624 1562 10328 1164 63831 506 409 2164 824 4.10 2705 24430 454 571 3682 1795 10621 1139 61642 460 396 2215 748 4.11 2696 23833 492 704 3638 1692 10252 1015 63527 511 497 2058 793 4.12 2549 24209 493 537 3606 1760 10456 969 65288 492 342 1999 637 4.13 2706 24969 529 443 3738 1610 10271 1324 62299 449 254 2221 867 4.14 2699 24356 512 482 3724 1663 10438 1128 60842 526 385 2221 958 4.15 2606 21905 530 574 3584 1732 9949 991 63027 544 335 2084 860 4.16 2580 22759 455 563 3867 1784 10112 985 61952 516 410 2102 800

146

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

4.17 2510 23005 413 546 3530 1703 10351 1159 64427 427 341 2289 953 4.18 2377 22352 462 438 3442 1518 10210 1128 65757 442 392 2120 865 4.19 2498 23533 607 583 3623 1454 10415 915 62565 430 317 2199 761 4.20 2479 22651 508 579 3622 1574 10234 1037 63683 375 359 2157 990 4.21 2518 23465 436 339 3830 1529 10419 1064 57906 421 421 2134 608 4.22 2653 25176 508 720 3726 1545 10838 935 57696 454 318 2319 641 4.23 2621 24405 477 479 3709 1609 10719 1044 57567 460 313 2198 847 4.24 2664 24858 442 641 3900 1723 10443 916 60159 475 369 2234 682 4.25 2408 24754 534 600 3613 1518 10600 1126 61003 444 394 2182 769 4.26 2535 23599 510 824 3632 1494 10719 888 57707 524 385 2355 628 4.27 2574 24421 534 710 4021 1700 11014 940 61273 509 445 2296 746 4.28 2835 26419 405 585 3777 1659 11224 1009 58953 523 448 2303 958 4.29 2541 23653 541 865 3878 1541 10537 859 65215 472 354 2069 762 4.30 2811 25068 385 775 3988 1650 10761 892 64230 506 363 2091 766 4.31 2597 25005 378 596 4039 1626 10808 866 64904 492 420 2240 803 4.32 2728 25782 492 779 3925 1600 10801 868 62452 515 379 2212 791 4.33 2641 26156 499 717 3930 1495 10979 824 58548 513 427 2427 668 4.34 2538 24160 399 928 3875 1552 10533 1055 63015 520 363 2204 802 4.35 2514 24203 462 434 3863 1528 10352 850 61031 541 375 2244 683 4.36 2513 23201 488 740 3755 1529 10601 811 59201 521 440 2207 827 4.37 2511 22932 469 494 3630 1332 10517 731 60387 536 422 2298 755 4.38 2493 23612 479 527 3921 1406 10479 777 65022 493 325 2116 805 4.39 2353 23434 504 515 3606 1346 10588 785 64444 475 363 2411 744 4.40 2445 22620 501 685 3717 1421 10243 754 62585 514 422 2344 771 4.41 2604 24927 514 702 3852 1458 10903 675 62288 509 363 2364 670 4.42 2544 23816 405 386 3860 1505 10337 821 62612 420 459 2400 838 4.43 2307 22321 465 787 3679 1438 10367 735 60613 475 385 2406 817 4.44 2597 25051 569 540 3876 1423 11063 816 62762 477 441 2429 845

147

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

4.45 2707 24908 456 613 3996 1501 10954 882 62715 510 347 2477 737 4.46 2943 25425 534 757 4065 1542 11066 733 61456 507 386 2421 822 4.47 2972 25046 351 628 3952 1592 10852 584 65804 479 342 2359 746 4.48 3106 26621 462 664 4135 1556 11043 799 64357 482 337 2319 552 4.49 3057 27030 484 692 4159 1442 11561 936 61230 530 414 2534 774 4.50 2896 24780 487 699 3919 1383 10665 808 61875 433 410 2264 855 4.51 3026 26390 415 418 4050 1415 11089 704 61362 469 448 2333 883 4.52 3097 26966 386 546 3969 1412 11129 670 62168 517 363 2402 712 4.53 3053 26752 452 684 3938 1380 11045 638 62547 460 404 2380 635 4.54 3098 26777 449 472 3910 1389 11083 738 59563 477 428 2359 763 4.55 2912 26836 429 657 4115 1449 11284 650 57732 500 420 2373 722 4.56 2172 22056 476 597 3773 1280 10863 630 58415 479 440 2527 721 4.57 2546 23595 557 415 3630 1268 10220 823 57314 450 375 2361 823 4.58 2801 26767 538 630 4078 1595 11356 638 60664 446 394 2611 768 4.59 2927 26889 489 595 4019 1376 11033 540 58221 511 519 2514 772 4.60 2683 25523 452 617 3967 1418 10844 507 59234 528 385 2462 777 4.61 2814 25936 466 595 3956 1397 11231 562 58976 490 448 2554 762 4.62 2900 29853 498 568 4002 1153 11540 668 55677 498 470 2597 886 4.63 2949 27003 481 365 4095 1356 11242 526 57656 563 358 2508 963 4.64 2906 29630 406 534 3746 1275 11495 560 54186 523 406 2534 744 4.65 2890 26906 350 409 3910 1465 11224 478 57603 462 374 2562 714 4.66 3006 27832 552 722 4020 1411 11419 493 57228 479 399 2686 813 4.67 2901 26896 416 463 4068 1405 11453 461 56005 528 448 2566 920 4.68 2912 27365 470 664 3954 1454 11452 477 56200 571 484 2588 754 4.69 3109 26715 477 419 3846 1327 11569 685 58496 541 437 2507 971 4.70 3018 26758 488 827 3927 1446 11454 477 54216 607 469 2473 940 4.72 3020 27871 495 636 4088 1381 11009 679 53328 675 451 2750 792 4.73 2933 26697 579 666 3789 1399 10848 598 51535 512 343 2641 840

148

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

4.74 2919 27429 368 754 3933 1460 10916 545 50873 494 364 2650 886 4.75 3153 30042 512 737 4084 1492 11308 735 51920 518 453 2802 633 4.76 2378 22165 533 735 3242 1153 9480 501 43743 488 391 2398 741 4.77 3132 27820 437 638 4005 1496 11383 599 53075 479 407 2582 857 4.78 2980 27178 440 673 4034 1370 10869 568 53825 403 308 2364 663 4.79 2990 27143 572 702 4090 1232 10282 552 48106 435 358 2333 519 4.80 2979 26164 492 457 3828 1314 10348 551 48019 444 368 2261 778 4.81 2859 27973 436 635 3869 1356 11029 580 47919 488 468 2655 612 4.82 3012 28005 476 518 3944 1396 11184 578 48430 460 425 2525 668 4.83 2891 26815 515 921 3741 1249 10666 467 45482 418 368 2573 828 4.84 2870 24741 515 553 3702 1363 10050 412 49849 501 332 2393 689 4.85 2864 25962 453 578 4038 1219 10328 332 48858 566 352 2578 650 4.86 3050 26930 568 698 3834 1406 11027 574 45514 562 346 2890 825 4.87 2947 25302 480 789 3850 1385 10525 504 49564 594 438 2658 796 4.88 2958 25630 414 778 3781 1541 10542 418 49921 530 409 2846 757 4.89 2903 25732 619 681 3918 1417 10649 305 48736 567 368 2997 861 4.90 2840 23850 500 704 3792 1437 10318 347 49301 560 427 2591 896 4.91 2920 24727 604 753 3863 1420 10728 255 48143 585 459 2765 846 4.92 2911 24169 556 688 3756 1595 10913 505 46945 627 398 2845 749 4.93 2453 22563 578 602 3526 1667 10367 441 45784 525 389 2703 985 4.94 1422 11183 780 730 1997 1938 5425 453 39556 532 412 2022 708 4.95 2790 22462 576 632 3720 1456 9380 716 44265 609 363 2591 664 4.96 1581 12189 573 323 2102 2236 6019 438 42021 509 328 2008 684 4.97 2079 14220 591 648 3026 1700 6620 301 47129 651 505 1906 737 4.98 2552 15890 474 541 3541 1854 6118 239 44196 664 353 1794 724 4.99 2311 14865 512 459 3202 2018 5514 300 48112 746 454 1590 895 5.00 2480 16571 611 676 3497 1891 6371 249 47968 776 426 1676 695 5.01 2673 17197 624 588 3760 2213 6692 289 46537 886 458 1706 844

149

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

5.02 2293 14879 586 657 3498 2129 6414 217 48180 767 375 1597 904 5.03 2826 17710 576 722 3920 2158 6800 294 52632 800 395 1831 845 5.04 2126 13712 547 717 3089 1731 5670 204 43124 747 436 1674 902 5.05 2902 19368 655 654 4099 1491 7313 242 44300 710 280 1725 886 5.06 3205 21931 631 579 4423 1622 7705 380 40084 786 301 1913 778 5.07 2269 16211 654 428 3258 1752 6385 352 41341 691 353 1810 772 5.08 2672 18294 611 279 3861 1367 7462 261 39772 846 410 1992 740 5.09 1990 13475 751 340 2732 1589 5528 317 35895 765 365 1778 736 5.10 2844 20492 645 551 4170 1490 7270 302 38366 819 333 1862 892 5.11 2980 20450 654 550 4198 1654 7362 380 40693 786 338 1900 919 5.12 3197 22425 561 743 4810 1573 8387 327 41463 945 382 2104 755 5.13 3353 22791 416 610 4682 1610 8026 132 41837 877 424 2034 791 5.14 3152 22689 599 542 4368 1582 8141 342 41101 1010 377 2082 709 5.15 3413 24427 455 341 4605 1557 8378 241 37646 909 299 2331 959 5.16 3145 23355 489 593 4640 1388 8378 362 37630 915 365 2107 1041 5.17 2945 21049 505 722 4230 1450 7927 386 34997 918 337 2258 667 5.18 2787 20019 545 676 3882 1256 7635 215 32973 793 326 2137 728 5.19 2742 19053 521 584 4008 1311 8064 307 36611 727 286 1987 669 5.20 2092 15786 601 644 3267 1389 6956 248 35914 761 407 1818 797 5.21 2473 20365 722 413 3995 1419 8146 339 36628 773 344 2233 929 5.22 2661 22314 485 651 3854 1108 8284 380 35494 747 374 2389 751 5.23 2595 21185 520 652 3798 1118 7842 418 38598 887 360 2345 984 5.24 1751 13294 862 716 2654 1813 5847 301 50753 606 303 1865 963 5.25 2251 18991 665 809 3162 1179 7183 359 30882 674 373 2836 711 5.26 2940 28033 591 580 4134 1125 8677 464 29116 695 368 3261 931 5.27 2744 25118 596 969 3876 1241 7881 393 30523 705 396 2923 848 5.28 2967 26916 562 853 4314 1256 8403 466 31595 699 280 2892 922 5.29 3295 30156 475 501 4382 1277 9021 425 33533 718 402 3323 1127

150

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

5.30 3257 28290 609 467 4255 1089 8480 493 32691 779 337 3054 742 5.31 2922 25199 542 496 3919 1091 7876 314 31300 711 348 3059 858 5.32 2522 22250 568 945 3841 1104 8020 202 33813 714 357 2859 880 5.33 3560 31931 589 699 4610 1344 8609 444 30283 662 268 3391 899 5.34 2949 26018 543 607 4086 980 7727 356 31533 669 290 2963 932 5.35 3457 29123 575 666 4659 1246 8820 385 33745 736 318 3252 943 5.36 2734 24044 598 559 3778 991 7447 474 28525 605 370 2674 973 5.37 3652 33112 543 954 4858 1335 8402 611 30084 697 322 3272 974 5.38 3859 33967 489 734 4973 1230 8355 551 29321 735 294 3553 1096 5.39 3789 32006 489 541 4785 1204 8482 448 31411 722 349 3540 978 5.40 3986 33968 465 849 4973 1225 8869 410 32190 743 293 3659 1004 5.41 4173 35301 551 939 5054 1255 8557 459 31762 762 346 3870 1069 5.42 4116 36090 401 943 5044 1179 8731 431 32351 686 324 3710 967 5.43 4322 36731 497 815 5331 1465 9333 529 34954 762 386 3724 942 5.44 4328 36541 404 637 5143 1391 8972 535 32611 774 325 3438 1044 5.45 4178 35981 432 551 5088 1198 8796 424 30889 780 346 3705 1019 5.46 4160 35325 435 560 5073 1317 8624 487 30523 760 309 3648 1026 5.47 3822 33065 506 620 4751 1058 8802 357 31146 694 278 3415 736 5.48 4137 35834 411 292 4876 1218 8862 594 30094 789 297 3394 1121 5.49 3911 33663 509 508 5095 1242 8870 382 31992 772 322 3358 953 5.50 3656 32599 497 807 4870 1201 9049 404 34469 717 368 3263 989 5.51 3894 34190 457 869 4844 1150 8690 444 30882 740 390 3449 1105 5.52 4065 35350 553 574 5226 1145 8849 409 30265 778 380 3762 1147 5.53 3991 34677 599 705 4949 1092 8770 479 32452 760 383 3651 973 5.54 4003 34204 529 801 5031 1274 8823 398 33016 806 241 3686 919 5.55 4119 33283 359 985 4789 1113 8252 451 30962 685 411 4396 1144 5.56 4130 31758 420 776 3810 1419 9228 400 36060 489 335 3659 1061 5.57 4368 29189 371 769 3464 1337 9189 290 41351 455 399 3305 944

151

Table A-8. Continued Depth (mblf)

Al

Si S Cl K Ca Ti Mn Fe Rb Sr Zr Ba

5.58 4433 27151 480 742 3455 1492 8982 368 45625 510 356 2971 902 5.59 4066 26325 519 822 3262 1336 8597 190 48853 575 349 2809 914 5.60 4351 26854 368 443 3356 1357 8584 425 48295 559 341 2994 885 5.61 3295 21374 390 406 2412 1007 6849 273 35208 427 228 2320 585 5.68 4757 40557 351 494 5599 1284 9185 488 30866 770 338 4213 1224 5.69 4715 38429 590 503 5299 1214 8628 312 32211 672 321 4094 1020 5.70 4408 31009 401 458 3563 1343 9062 440 40081 644 368 3308 854 5.71 4087 27786 409 99 3156 1274 8596 360 42438 527 293 3046 756 5.72 4180 28363 401 301 3197 1220 8614 222 39999 457 293 3167 958 5.73 3703 26669 410 98 2958 1379 8403 326 38572 526 275 3224 979 5.74 3944 29912 508 194 3431 1196 8691 274 36278 573 355 3434 794 5.75 4249 30842 450 243 3868 1160 8533 563 38252 556 321 3533 849 5.76 4458 25662 483 316 3002 1158 8890 317 51902 477 319 2900 751 5.77 4911 29370 501 298 2952 1148 9715 327 49898 471 311 2887 793 5.78 4907 28005 477 328 2855 1241 9648 411 52106 472 333 2619 745 5.79 4111 21897 440 268 2597 1350 8716 355 69641 508 261 2202 885 5.80 4152 20753 421 225 2555 1298 8212 357 67079 469 323 2010 937 5.81 4699 24661 367 319 2845 1300 8937 416 79510 448 295 2256 879 5.82 4405 24425 425 44 2369 1305 9137 596 88344 302 225 2014 717 5.83 4605 24510 441 155 2435 1074 9259 425 75052 390 263 2183 706 5.84 4767 24904 370 217 2555 1127 9400 401 65721 415 280 2279 879

152

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154

BIOGRAPHICAL SKETCH

Mary Beth Day grew up in Seneca Falls, NY. In 2007, she graduated summa cum laude

from Hamilton College (Clinton, NY) with a BA in geoarchaeology. Her undergraduate thesis,

supervised by Dr. Eugene Domack, examined a new technique for improving the accuracy of

radiocarbon dates of Antarctic marine sediments. While an undergraduate, she was awarded a

Goldwater Scholarship and named to the USATODAY All-USA Academic Team. She will

enroll at the University of Cambridge in the fall to earn a Ph.D. in Earth Sciences as a Gates-

Cambridge Scholar. In her free time, Mary Beth enjoys hunting and gathering.