Western Michigan University ScholarWorks at WMU
Master's Theses Graduate College
6-2003
Stratigraphy of Lake Michigan Lobe Deposits in Van Buren County, Michigan
Steven P. Beukema
Follow this and additional works at: https://scholarworks.wmich.edu/masters_theses
Part of the Geology Commons
Recommended Citation Beukema, Steven P., "Stratigraphy of Lake Michigan Lobe Deposits in Van Buren County, Michigan" (2003). Master's Theses. 4445. https://scholarworks.wmich.edu/masters_theses/4445
This Masters Thesis-Open Access is brought to you for free and open access by the Graduate College at ScholarWorks at WMU. It has been accepted for inclusion in Master's Theses by an authorized administrator of ScholarWorks at WMU. For more information, please contact [email protected]. f
STRATIGRAPHY OF LAKE MICiflGANLOBE DEPOSITS IN VAN BUREN COUNTY, MICiflGAN
by Steven P. Beukema
A Thesis Submitted to the Facultyof The Graduate College in partial fulfillmentof the requirements forthe Degree of Master of Science Departmentof Geosciences
WesternMichigan University Kalamazoo, Michigan June 2003 Copyright by Steven P. Beukema 2003 ACKNOWLEDGMENTS
There are several people who deserve recognition for their generous support. I would first like to thank Bill Bush forsuggesting the idea of doing graduate work in geology at WMU. Two of my cohorts in the department, Andrew Kozlowski and Brian Bird, deserve special recognition for endless hours of ruminating with me about many things, in particular about the last 20,000 years in southwest Michigan. I wish also to thank Andrew forstepping out of his pessimistic outlook to offerme continual encouragement to pursue science and academia. Brian was always willing to spend time making figures and answering my constant questions about GIS, Canvas, and a host of other programs. I would also like to thank Brian for motivating me and for helping me stay close to my desired schedule when it came time to start writing. I would like to thank the USGS STATEMAP program for two years of funding while working on this project. My committee members, Dr. David Barnes and Dr. William Sauck, deserve recognition for their helpful comments and advice. My main advisor, Dr. Alan Kehew, deserves my gratitude and recognition for his guidance, insight, advice, and for being a great guy to work with. Finally, I would like to thank my family for being supportive of me during these endless years as a professional student.
Steven P. Beukema
ii STRATIGRAPHY OF LAKE MICID GAN LOBE DEPOSITS INVAN BUREN COUNTY, MICIDGAN
Steven P. Beukema, M.S.
WesternMichigan University, 2003
The surficial glacial deposits and landforms of Van Buren County were recently mapped at a 1:24,000 scale as part of a STATEMAP project. Several borings were drilled to supplement the surface data. Six of these borings were characterized in detail by means of gamma ray logging, textural analysis, and X-ray diffractionof the clay-sized fractionof the diamicton units. Results from this study reveal two diamicton units at stratigraphicallydistinct positions that can be correlated across the county and that are separated by a thick sequence of lacustrine sediments. Correlation of diamicton and lacustrine units was accomplished by analyzing several factors, including topography, stratigraphic position, texture, and clay mineralogy. The diamicton units in this study correlate to an upper and lower diamicton at the bluffs of Lake Michigan as well as to inland surface diamictons that Monaghan et al. (1986) characterize and informally name the Saugatuck and Ganges tills. This stratigraphy also correlates with other regional studies (Wong, 2002; Bird, in preparation) and suggests an advance of the Lake Michigan Lobe at least as far as the Kalamazoo Moraine, a subsequent retreat of the lobe with a significantperiod of a lacustrinedeposition, followedby a readvance. TABLE OF CONTENTS
ACKNOWLEDGMENTS ...... n
LIST OF TABLES ...... vi
LIST OF FIGURES...... Vil
LIST OF EQUATIONS ...... X
LIST OF PLATES...... XI CHAPTER I. INTRODUCTION...... 1 Scope of Research andObjectives ...... 1 Location andRegional Glacial Geologic Setting ...... 3 Bedrock Geology...... 6 Glacial Geology...... 8 Regional Glacial Geology...... 8 Glacial Geology of the Study Area ...... 11 Glacial History / PreviousWork...... 14 II. METHODS ...... 25 Field Methods...... 25 Laboratory Analysis...... 25 Textural Analysis Procedure...... 25 X-ray Diffractionof Clay Minerals...... 28 Computer Analysis...... 32 Processing of Gamma Ray Logs...... 32 iii Table of Contents-continued
Processing of Sieve Data ...... 33
Processing of XRDData...... 34
Postprocessing of Data...... 35
III. RESULTS...... :...... 36 Individual Core Descriptions...... 36
VB-99-03 ...... 36 VB-0 l-07...... 43
VB-01-09 ...... 46 VB-02-01...... 57
VB-02-02 ...... 61 VB-02-03 ...... 69
IV. DISCUSSION...... 78
Correlation of Diamicton Units...... 78
Stratigraphic Position...... 78 TopographicConsiderations ...... 80
Textural Comparisons...... 85
Insights from Clay Mineralogy ...... 89
VB-02-03...... 93 Correlation of Lacustrine Units...... 97 Stratigraphic Position...... 98
Topographic Considerations ...... 98
Textural Comparisons...... 100
iv Table of Contents-continued
Insights from Clay Mineralogy ...... 102 Correlation with Other Data...... 103
Grain Size Statistical Parameters...... 104
V. CONCLUSIONS...... 108 APPENDICES A. Textural Analysis Results...... 112 B. X-ray DiffiactionResults...... 127
C. Stokes's Law...... 130 D. Student's t-test ...... 133 BIBLIOGRAPHY...... 136
V LIST OFTABLES
1. X-ray diffractionproperties of select clay minerals...... 29
2. X-ray Diffractometer settings································'.·················"·················· 33
3. Average texture by unit for VB-99-03 ...... 39
4. Average texture by unit forVB-01-07 ...... 45 5. Average texture by unit for VB-01-09 ...... 51
6. Average texture by unit forVB-02-01 ...... 59 7. Average texture by unit forVB-02-02...... 65
8. Average texture by unit forVB-02-03 ...... 71 9. t-test results forthe comparison of diamicton units...... 90 10. t-test results forthe comparison of diamicton units fromVB-02-03 to VB-01-09...... 95
vi LIST OF FIGURES
1. Map of Michigan showingVan Buren County...... 3
2. Map ofVan Buren County showing boring locations...... 4 3. Moraines mapped by Leverett and Taylor (1915) ...... 5 4. Bedrock map of Michigan...... 7
5. Bedrock topography of Van Buren County...... 9 6. Regional map outlining the areas affectedby lobes of the Laurentide Ice Sheet...... 10
7. Global temperature curve fromCambrian to present...... 15 8. Diachronic and chronostratigraphic correlation of Pleistocene Units in the Midwest...... 17
9. Generalized stratigraphyof southwest Michigan...... 23
10. Example of an X-ray diffractogram...... 31
11. Composite log forVB-99-03 ...... 3 7
12. Matrix texture forsamples ofVB-99-03 upper diamicton...... 40 13. Matrix texture for samples ofVB-99-03 lower diamicton...... 41
14. Histogram of 7 All 0A ratios forVB-99-03 lower diamicton ...... 42
15. Composite log forVB-0 1-07 ...... 44
16. Histogram of 7A/10A ratios forVB-01-07 lacustrine Unit 4...... 47
17. Histogramof 7A/10A ·ratios forVB-01-07 lacustrine Unit 6 ...... ;...... 48 18. Composite log forVB-01-09 ...... 50
19. Matrix texture for samples ofVB-01-09 upper diamicton...... 52
20. Histogram of 7All0A ratios forVB-01-09 upper diamicton ...... 53
Vll List ofFigures-contin ued
21. Histogramof 7 A/1 0A ratios forVB-01-09 lacustrine unit...... 54
22. Matrix texture for samples of VB-01-09 lower diamcton ...... 55
23. Histogramof7A/10A ratios for VB-01-09 lower diamicton ...... 56
24. Composite log forVB-02-01 ...... :...... 58 25. Matrix texture forsamples ofVB-02-01 upper diamicton...... 60 26. Matrix texture forsamples ofVB-02-01 lower diamicton...... 61
27. Histogram of7Al10A ratios forVB-02-01 lower diamicton ...... 62
28. Composite log for VB-02-02 ...... 64
29. Matrix texture forsamples of VB-02-02 upper diamicton...... 66 30. Matrix texture forsamples ofVB-02-02 lower diamicton...... 67 31. Histogram of7 All 0A ratios for VB-02-02 lower diamicton ...... 68
32. Composite log forVB-02-03 ...... 70
33. Matrix texture for samples ofVB-02-03 upper diamicton...... 72
34. Histogram of 7AIIOA ratios forVB-02-03 upper diamicton ...... 73
35. 7All0A ratios with depth forVB-02-03 ...... 74 36. 7All0A and gamma ray log with depth forVB-02-03...... 75
37. Matrix texture forsamples of VB-02-03 lower diamicton...... 76
38. Histogram of7 All 0A ratios for VB-02-03 lower diamicton ...... 77 39. Topographic profile A-A' over a DEM basemap...... 81 40. Topographic profileB-B' over a DEM basemap ...... 82
41. Topographicprofile C-C' overa DEM basemap ...... 83
42. Topographic profileD-D' over a DEM basemap...... 84
viii List of Figures-continued
43. Matrix textures fromall of the diamicton samples ...... 86
44. Saugatuck till matrix textures...... 87
45. Ganges till matrix textures...... 88
46. 7All0A vs. 14All0A ratios for diamicton samples heated to 315°C...... 94 47. Lacustrine elevations and thicknesses ...... 99 48. Mean grain size versus sorting for316 samples ...... 105
49. Mean grainsize versus skewness for316 samples ...... 106
50. Generalized cross section of Van Buren County, Michigan ...... 109
ix LISTOF EQUATIONS
1. The BraggEquation ...... 30
2. Mean (1st moment)...... 34
3. Standard deviation (2nd moment)...... 34
4. Skewness (3rd moment)...... 34 5. Kurtosis (4th moment)...... 34
6. Stokes's Law...... 131
7. t calculation...... 134
8. Degreesof freedom...... 134
X LIST OF PLATES
1. Glacial terrain map of Van Buren County...... 141
xi 1
CHAPTER I
INTRODUCTION
Scope of Research and Objectives
The surficial glacial deposits and landforms of Van Buren County, Michigan were recently mapped at a 1:24,000 scale as part of a STATEMAP project that was partially funded by the U. S. Geological Survey under a subcontract with the
Michigan Department of Environmental Quality (Kehew et al., 2002). Fieldwork for the 7.5 minute quadrangles involved examining exposures in road cuts, along riverbanks, in sandpits, and in gravel pits. Additional fieldinformation was obtained through hand auguring to a depth of approximately 1.5 meters. Complementary information ':"as procured by studying topographic maps, digital orthophoto quadrangles, previously published maps of the area (Terwilliger, 1952; Leverett and
Taylor, 1915), and soil surveys.
Several boreholes were drilled each year of the four-year project for the
purpose of collecting subsurface data. These cores have been obtained by means of
Rotasonic drilling technology, which allows for the collection of continuous cores of
4" diameter with minimal loss. This project is an analysis of six of these cores,
drilled during the field seasons of 1999, 2001, and 2002. Five of these cores were
drilled on upland areas while one core, VB-01-07, was drilled on a lowland. The 2 boreholes were gamma ray logged immediately after drilling, and the cores were described in the field as they were drilled. Each core was transported to a lab for textural analysis. Samples from each core were analyzed texturally by sieves and by settling velocities to determine the percentage of gravel, sand, silt, and clay, as well as to obtain detailed information regarding grainsize distribution. Diamicton units were further characterized by X-ray diffraction (XRD) of the clay-sized particles.
Researchers have been able to characterize and correlate diamicton units across
Michigan based on the 7AllOA ratio with questionable success (Monaghan and
Larson, 1986; Rieck et al., 1979; Gardner, 1997; Flint, 1999; Wong, 2002). Clay mineralogy was also studied on a few additional samples in material other than diamicton.
The cores were divided into several units and, together with the accompanying gamma ray logs, were compared with each other and to other gamma ray logs in the county in order to attempt to determine stratigraphic units as well as to correlate the units across the county. In addition to the correlation, these cores provide invaluable information regarding the stratigraphy of the landforms on which they were drilled.
Upland features from which cores were derived include a drumlin, a terminal moraine, and features of unknown but probable subglacial or ice marginal origin.
The goals of this study are to describe and characterize units from the six
Rotasonic cores. These characterizations will be compared to previous studies with the intention of being able to correlate units across southwest Michiganand to further establish characteristics of the till units to lead to the development of recognized 3 glacial stratigraphic units for the region. Further goals include evaluating the usefulness of the clay mineralogy studies. In addition to this, statistical parameters, including mean grain size, sorting, skewness, and kurtosis, were utilized to detennine if any they can be applied meaningfullyto glacial sediments.
Location and Regional Glacial Geologic Setting
The location of the study area is Van Buren County, Michigan (Figure 1).
Van Buren County lies between Kalamazoo County and Lake Michigan in
Figure 1. Map of Michigan showing Van Buren County 4 southwestern Michigan, approximately 40 km north of the Indiana border. The cores
for this study were drilled at key locations across Van Buren County, Michigan
(Figure 2). Major glacial landfonnsof the area, as originally mapped by Leverett and
Taylor (1915), are shown in Figure 3. These include a portion of the Kalamazoo
VB-99-03• •VB-02-02
Legend VB-01-07• Meters VB-02-01 ♦ 177- 200 - 301 -325 • 201- 225 - 326- 350 - 226-250 - 351-375 - 251-275 - 376-400 - 276-300 - 401-425
• Rota9onk:Borings 0 5 10 '----'----'------'----' Kilometers
Figure 2. Map of Van Buren County showing boring locations (USGS DEM)
morame in the southeast comer of the county, where the highest elevations are
reached. The Kendall moraine, considered by Leverett and Taylor (1915) to be part 5 of the Kalamazoo moraine, occupies the northern part of the county. The VB-99-03 core was drilled on this feature. A relatively wide uplandarea originally mapped by
..Ji�/\
N
A \/{}'
0 2.5 5 10 Miles Moraines Mapped by Leverett and Taylor I I I I II I � Kalamzoo J 2.5 5 1 O Kilometers � Kendall CJLake Border h
Figure 3. Moraines mapped by Leverett and Taylor (1915)
Leverett and Taylor (1915) as the Valparaiso moraine makes up the middle portion of
the county. The VB-01-09 core was drilled on a drumlin in the Valparaiso moraine 6 complex. Dissecting these upland features is the Paw Paw River Valley, which extends from a lowland west of the Kalamazoo moraine to its outlet into Lake
Michigan, to the west. VB-01-07 was drilled in this valley. Another upland ridge oriented parallel to the Kendall and Valparaiso moraines is the Lake Border moraine, a narrow ridge near the shore of Lake Michigan. VB-02-03 was drilled on the crest of this ridge, and VB-02-01 and VB-02-02 were drilled on isolated upland features near the ridge.
Bedrock Geology
The bedrock geology of the Lower Peninsula of Michigan consists of sedimentary rocks including shale, sandstone, limestone, and dolomite, as well as evaporites including gypsum and halite (Dorr and Eschman, 1970). These rock units form a structural basin known as the Michigan Basin, with the oldest rocks of
Cambrian age subcropping in a ring-like pattern at the edge of the basin in parts of
Michigan's Upper Peninsula, Wisconsin, Illinois, Indiana, and Ontario, Canada. The
subcropping rocks become progressively younger with age toward the center of the
structural basin, which roughly coincides with the center of the Lower Peninsula.
The rocks at the center of the basin are red beds of Jurassic age. Michigan's bedrock
geology is shown in Figure 4, with the study area of Van Buren County outlined. The
only rock unit to subcrop in Van Buren County is the Coldwater Shale of
Mississippian age. The Coldwater Formation was described by Dorr and Eschman
(1970) as having a maximum thickness of 400 meters and consisting of blue to gray 7
i i
Pffln,vlvarn'.an Pgr Grand River Ps Saginaw Mi.1iui71Pian Mb Bayport Mm Michigan Mnm Napoleon-Marshall Mc Coldwoler Mbb Berea-Bedford Me Ellsworlh•Antrim Miui.al1ppi411 Dno"ia" M·Do An1rim lM1.·1uiicn Dt Traverse Ore Rogers City Dd Dundee Ddr Detroit River Dbb Bois Blanc Deucmia.n Siluri4n D·Sm Mackinac breccio Siluria11 Sbi Boss Island Ssi St. Ignace Sp Point Aux Chenes Se Engadine Sm Manistique Sbb Burnt Bluff Sme Mayville Ordovida• Dr Richmond Oc Collingwood Ot Trenton Obr Block River Oh Hermonsville Ca.fflbria.n Cm Munising Cj Jacobs ville 50 MILES C Cambrian undivided
Figure 4. Bedrock map of Michigan (Dorr and Eschman, 1970) 8 shale interbedded with carbonate concretions.
Recent studies (Rieck, 1976; Bird, in preparation; Nicks, unpublished data) have suggested that bedrock topography may influencethe glacial topography. There is a bedrock high that coincides with the western part of the Kalamazoo moraine
(Figure 5). A similar bedrock high is located under a portion of the Valparaiso moraine. The Lake Border moraine, however, displays the opposite relationship with bedrock topography. A deep trench that could be a bedrock valley directly underlies the Lake Border moraine. Bedrock elevations in this trench are as low as 30 meters above sea level. The drift thickness of the Lake Border moraine approaches 200 meters, much of which could be pre-Wisconsinan drift(Leverett and Taylor, 1915).
Glacial Geology
Regional Glacial Geology
The surficial glacial deposits of SouthwesternMichigan were deposited by the
Saginaw and Lake Michigan lobes of the Laurentide Ice Sheet (Leverett and Taylor,
1915; Zumberge, 1960; Monaghan and Larson, 1986) (Figure 6). The city of
Kalamazoo roughly coincides with the interlobate region, with Saginaw lobe deposits primarily to the east and Lake Michigan lobe deposits primarily to the west. To the east of Kalamazoo lie the Tekonsha moraine and the Saginaw arm of the
Kalamazoomoraine, both trending NW-SE. These landforms, and others to the north and east with similar orientations, were probably deposited by the Saginaw lobe. 9
N A 0 2.5 5 10 Miles Bedrock Topography I I I II I I I I I Elevation in Meters O 2.5 5 1 O Kilometers D 180-210 - 00-120 D 150-180 - oo-9o 1111120 - 150 1111so - 60
Figure 5. Bedrock topography of Van Buren County (modified fromBird, in preparation) 10
86°0'0'W 84°0'0'W 82'0'0'W BO'O'O'W
46°0'0''N 46°0'0"N +
·o·o·'N 44°0'0"N +
Saginaw . ./" � Lobe
<� \ °0'0''N 42 42°0'0"N
- , , ' / ___ , .;/.' , jl_ , , - - - .,- -... '- ... 14:S ka BP -
O'O'O"N 4o•o·o"N + /"'-�+ f 1 .. .. :, ..J,,� L'' 20-21... ka BP .....
Indiana
86°0'0'W 84'0'0'W s2°o·o·w
Figure 6. Regional map outlining the areas affectedby lobes of the Laurenti de Ice Sheet (modifiedfrom Fullerton, 1986) 11 Landfonns to the west have orientations that can be explained by deposition by the Lake Michigan lobe, including ridges with NE-SW orientations and drumlins with NW-SE orientations. Although these surface features are in the realm that has been traditionally mapped as Lake Michigan lobe deposits (Leverett and Taylor,
1915), the Saginaw lobe may have played a role in sh�ping the landscape west of
Kalamazoo. Outwash deposits from Saginaw lobe meltwater are likely to have traveled to the west. Kozlowski (in preparation) argues that Lake Michigan lobe deposits have been trenched by a catastrophic outburst flood of Saginaw lobe meltwater that is responsible for carying the Kalamazoo River Valley in Kalamazoo
County. In addition to this, there may be palimpsest features, such as tunnel valleys, that may be the result of the Saginaw lobe, in areas that were later overridden by the
Lake Michigan lobe (Kehew et al., 1999). Thus, landfonns in Van Buren County are primarily the result of the Lake Michigan lobe, but the extent of influence of the
Saginaw lobe remains unknown.
Glacial Geologyof the Study Area
The surficial glacial geology of Van Buren County was recently mapped and is shown in Plate 1 (Kehew et al., 2002). The county consists of lowlands with adjacent upland ridges that trend NE-SW. Partof the Kalamazoo moraine lies in the southeastern comer of the county. This upland area extends up to 300 meters above sea level, making it the highest topographic feature in southern Michigan. The moraine consists of surficial sand and gravel deposits, with areas of abundant 12 boulders near the surface. Diamicton and bedded sands and silt also occur. Thrust ridges oriented transverse to the flow of the Lake Michigan lobe are also present in one part of the moraine. The western edge of the moraine is a steep scarp that could have been fonned or modified by wave or fluvial action. Directly west of the
Kalamazoo moraine are a few upland features mapped as ice-marginal deposits.
These are capped with diamicton at the surface and are oriented with their long axes
NE-SW. Wave-modified scarps occur on some of these features.
In the northeastern portion of the county is an upland that has been mapped as the Kendall moraine (Leverett and Taylor, 1915). This is a narrow ridge, with a width of less than 4 km, and a north-south length of approximately 15 km. It consists largely of sand and gravel at the surface, with a diamicton unit present at depth.
Leverett and Taylor originally grouped this moraine tentatively with the Kalamazoo moraine complex, qualifying that it could also be associated with the Valparaiso moraine immediately to the west {Leverett and Taylor, 1915).
In the central portion of the county is a broad upland area originally mapped by Leverett and Taylor as the Valparaiso moraine (1915). This upland area is largely dissected by postglacial fluvial activity, and it is comprised largely of defonned
lacustrine sediments that are discontinuously capped with diamicton. There is also a
small drumlin field, containing less than a dozen drumlins, with their long axes
oriented NW-SE, which is coincident with the Lake Michigan lobe flowdirection.
In the southwestern part of the county is a large upland area that has been
mapped as an uncollapsed, exposed fan deposit (Kehew et al., 2002). There are fan 13 head deposits located at the westernedge of the fan, indicating the source of the sand and gravel was to the west. Adjacent to the fan head deposits is a hummocky to rolling surface of moderate to high relief with a diamicton unit at the surface. A small portion of this is marked by a scarp of possible fluvial origin, as the Paw Paw
River flowsthrough the valley at the west end of the upland.
Several circular to irregular hills occur west of the Valparaiso upland region.
These uplands are of possible ice-marginal or subglacial origin and are comprised of sand to silt deposits discontinuously capped by a thin diamicton layer (Kehew et al.,
2002).
Another major feature is a narrow ridge that parallels Lake Michigan, with an orientation N-S/NE-SW. This ridge was mapped by Leverett and Taylor (1915) as the Lake Border moraine system of the Lake Michigan lobe. The ridge is comprised almost entirely of diamicton in Van Buren County.
The lowland areas of Van Buren County consist of sediments consistent with glaciolacustrine and glaciofluvial deposits. The modem Paw Paw River flows through this lacustrine plain and dissects some of the upland features,as it heads from its origins in the uplands of the Kalamazoo moraine to its outlet to the west in Lake
Michigan.
At the far western edge of Van Buren County is an area of eolian sand near the shore of Lake Michigan. This sand formsthe beach and also comprises dunes that reach up to 210 meters above sea level. The Holocene dunes occupy a band of
approximately 3 km fromthe edge of the lake. Sand dunes are located throughout the 14 county, especially between the present band of modem dunes and the Lake Border moraine, and also in the lowlands between the Lake Border and Valparaiso moraines.
Glacial History/Previous Work
According to oxygen isotopes measured on bentbic organisms in deep ocean sediments, the earth has been cooling since the mid-Cenozoic (Figure 7). Several key factors must coexist to result in an "ice house" climate. Changes in the Earth's orbit, known as Milankovitch Cycles, account for large and small scale changes in insolation. Large scale changes occur on the order of 100,000 years, whereas smaller scale changes occur on the order of 41,000 and about 20,000 years. A lower amount of incoming solar radiation is one factor in producing an ice house climate. In addition to this, there must be significant land situated near the polar regions.
Through ever-shifting continental plates, there is now, . and has been for several million years, abundant land near the poles in the Northern Hemisphere upon which ice could grow and spread. The location of continents also affects oceanic circulation, which is critical to ice-house conditions. The Pleistocene had the requisite conditions to produce great ice sheets that extend into the mid latitudes.
Our terrestrial record of Pleistocene glaciation is very limited, since, by its very nature, a glacial advance mar erode much of the sediment fromprevious glacial advances and will deposit new material that could later be eroded through paraglacial processes. The most detailed knowledge of glaciation that can be ascertained from the terrestrial record, therefore,is of the most recent advance over a particular area. 15
ESTIMATED MEAN GLOBAL TEMPERATURE
Ma COLD WARM
CENOZOIC
CRETACEOUS
JURASSIC
TRIASSIC
PERMIAN
CARBONIFEROUS
DEVONIAN
SILURIAN
ORDOVICIAN
CAMBRIAN
Figure 7. Global temperature curve fromCambrian to present (fromBradley, 1999)
The glacial coverage of North America was first outlined by Chamberlin
(1898), who recognized the maximum extent of ice near the Ohio River. Chamberlin divided the Pleistocene into four glacial periods: Nebraskan, Kansan, Illinoian, and
Wisconsinan. The Illinoian and Wisconsinan are still recognized today, although
Illinoian deposits in Michigan are poorly known and only encountered in the subsurface. 16 Separating the Illinoian from the Wisconsinan was an interglacial period known as the Sangamon Interglacial, named after a prominent paleosol in the
Sangamon River Valley in Illinois (Leverett and Taylor, 1915). Some researchers may have identified this paleosol in cores drilled in southern Michigan ( e.g. Flint,
1999).
Late Wisconsinan deposits are what constitute the surficial glacial drift in
Michigan. In the new diachronic units (Johnson et al., 1997), the Wisconsinan
Episode in southern Michigan can be separated into two subepisodes: the earlier
Athens Subepisode which includes the Altonian and Farmdalian substages of
Willman and Frye (1970), and the Michigan Subepisode, which began approximately
28,000 yr B.P (Johnson et al., 1997). The last glacial maximum occurred between
21,000 and 18,500 yr B.P (Dreimanis, 1977). Series of chronostratigraphic, diachronic, and lithostratigraphic units since the last glacial maximum are in use for the greater Great Lakes region (Figure 8). The landformsin Van Buren County were most recently formed or modified during the Crown Point Phase of the Wisconsinan
Episode (13,800-15,500 yr B.P.). The ice subsequently retreated out of Van Buren
County, followed by readvances that did not reach as far south as Van Buren County.
Kehew et al. (2000) dated wood from lacustrine deposits below a diamicton unit in
Allegan County at approximately 12,500 yr B.P. Similar dates could lead to a revision in the interpretation of the timing of the Lake Michigan lobe in southwest
Michigan.
The glacial landformsof Michigan and Indiana were firstextensively mapped 17
Chronostratlgraphlc Diachronic Units LlthostratlgraphlcUnits Units lllnoll Ind SW Indiana Michigan Wilconsm LMlchlaml 1 C : � .... 'TwoRinn Phna Two =. .!- (Glaciaq - ...... : :, -Mir...... <51/J ILe ILe :.--- I- 0 Two Cr-NiciPhue C C r-- 12 I- (TWOCll!llcs lnlarstadlal (l)lglacial) • • Cl • � Q • e ,, ,, Mbr. X llbr. s 0 0 r� f/J • • PortHuron Pha1e a. C PortHuron Sladlll Q, Q. (Glaclall Mllr. :, Cl w • - C C _-g -e lloflllGlle 'ii Mbr. Cl � C Ill C 13 C - .. 0 'ii! u C D •Q 'lle .. Q 0u E 0 .! II Mllc:tlnaw Pllua i Macldnawlnlfflladlal • � .0• (l)lglacial) :I i :i fl C• 'e r-- " .2 "8 CnlwnPoint Phan OakCnok Wadsworfll Wadnorfll Saugatuck PortBNC'I Stadia! (Glacial) Fm. Fm. TIii UI
loo- 15
MlwauuePlllse I Erle lnterstadlal (Olglaclaq
Figure 8. Diachronic and chronostratigraphiccorrelation of Pleistocene Units in the Midwest (from Kehew and Kozlowski, 2001). Scale in 1000s of years. by Leverett and Taylor (1915). They mapped ridges in southwest Michigan as a series of terminal moraines of the Lake Michigan lobe, fromoldest to youngest being the Kalamazoo, Kendall, Valparaiso, and Lake Border moraines.
Leverett and Taylor describe the Kalamazoo moraine as a system of two ridges, each between 2 and 6 km in width, separated by a gravel plain. The two ridges are referred to as the inner and the outer Kalamazoo moraine. The outer ridge 18 is characterized as containing many sharp knolls and basins along its entire length.
The inner ridge contains many more depressions than the outer ridge, and many of these open westward. There is less irregularity on the eastward side of the inner ridge. Near the vicinity of Decatur, Michigan, the gravel plain separating the inner and outer ridge is extensive and takes the place of the inner ridge (Leverett and
Taylor, 19 t 5). The stratigraphy of the moraine system varies, according to Leverett and Taylor, but it frequently contains a thin cap of clay with boulders at the surface,
under which is typically an extensive thickness of sand and gravel. A large lowland
filledwith outwash deposits exists immediately to the east of the Kalamazoomoraine; the outwash associated with the Kalamazoo moraine is one of the most extensive
outwash sheets in Michigan (Leverett and Taylor, 19 t 5).
Leverett and Taylor gave particular attention to the Kalamazoo Valley. They
describe it as a very wide valley cutting through the Kalamazoo moraine fromeast to
west and turning north, which is the opposite direction of typical glacial drainage.
They interpreted this valley as having formed fromthe result of stagnant ice fromthe
Lake Michigan lobe, and they credit the prolonged presence of ice in this valley as the
cause of the irregularities in the valley walls. Kozlowski (in preparation) argued that
this valley formed during a catastrophic subglacial outburst flood from the Saginaw
lobe.
The Kendall moraine was described by Leverett and Taylor as a "prominent
ridged belt which rises in an outwash apron east of the main part of the Valparaiso
system, in the northeastern part of Van Buren County" (1915). They "provisionally" 19 assigned it to the Kalamazoo system, although they stated that it might prove to be part of the Valparaiso system. It is a narrow ridge comprised of knob and basin topography and consists of large amounts of gravel and boulders, some of which are up to 2 or 3 meters in diameter. Leverett and Taylor noted the presence of a red jasper conglomerate boulder, typically associated with deposits of the Saginaw Lobe.
There is no diamicton at the surface, although a blue diamicton occurs at depth in some places.
Afterice retreated fromthe Kalamazoo and Kendall terminal positions, it later advanced, according to Leverett and Taylor (1915), to the Valparaiso position. Like the Kalamazoo moraine, the Valparaiso system was originally mapped as having an inner and outer component. Variations in topography along the extent of this moraine system range from abrupt to more subdued. Leverett and Taylor mention areas of knobs on the moraine that rise up to 25 meters above the surrounding land. Among areas containing these knobs are Van Buren and Allegan Counties. No detail or explanation is given regarding the stratigraphy or origin of these "knobs". Leverett and Taylor (1915) report the general composition of the Valparaiso moraine throughout Illinois, Indiana, and Michigan as consisting predominantly of blue clayey till in Illinois, a combination of till and sand and gravel in Indiana, and consisting of a greater amount of sand and gravel than till in Michigan. Leverett and Taylor say that though the ice border in the vicinity of Van Buren County does not have " ...so high an outwash apron as ..." areas along the moraine to the south, it. does have "along much of its length a narrow pitted plain ... " (1915). 20 The westernmostterminal position of the Lake Michigan lobe in southwestern
Michigan was mapped as the Lake Border moraine by Leverett and Taylor (1915).
Like the previously mentioned morainic systems, the Lake Border extends from
Illinois and Indiana into Michigan, where it follows the shore of Lake Michigan closely in southwestern Michigan, but less closely in northern Michigan. The moraine has the greatest topographic expression in northern Michigan whereas the portion of the moraine in southwestern Michigan is a thin ridge rising less than 50 feet above the surrounding land (Leverett and Taylor, 1915). Leverett and Taylor report that the drift on the moraine extends far below the level of Lake Michigan in places where the moraine is close to the Lake Michigan shore. There are occasional areas of shallower drift, and areas, such as by Ludington and Manistee, where the drift extends to a depth below sea level. Much of this material is thought to be pre
Wisconsinan in age. The composition of the moraine is largely sand and gravel in northern Michigan, whereas in southern Michigan the composition of the moraine is grayish-blue clayey diamicton. In southwestern Michigan the diamicton contains a relatively small amount of gravel, with very fewboulders. It is commonly underlain by laminated clay. When the ice was at its terminal position at the Lake Border moraine, glacial meltwater formed a lake in Van Buren and Allegan Counties that
was bounded by the Lake Border and the Valparaiso moraines. The elevation of the
lake was 210 meters (Leverett and Taylor, 1915). More recent research (Kehew,
personal communication) suggests a lake level up to 240 meters above sea level.
Terwilliger provided a more detailed glacial map of Van Buren County in his 21 "The Glacial Geologyand Groundwater Resources of Van Buren County, Michigan" publication of 1952. Terwilliger argued that the Kendall moraine is genetically associated with the isolated hills to the south, and together they are associated with the Kalamazoomoraine. He \\Titesthat the hills are covered with wind-blown sand, but otherwise are morainic in character (Terwilliger,. 1952). Like Leverett and
Taylor, Terwilliger mapped four morainic systems in Van Buren County. They are, from east to west: Kalamazoo, Kendall, Valparaiso, and Lake Border moraines.
Terwilliger identified a till plain between the Kalamazoo moraine and the isolated hills to the west, including the Kendall moraine and Prospect Hill. He also identified an outwash plain concentrated in southern Van Buren County that is associated with the Valparaiso moraine. Its elevation is around 250 meters and it is separated from the Valparaiso moraine by a series of pits 6 or more meters in depth. Terwilliger noted an absence of outwash in front of the Lake Border moraine in Van Buren
County. Separating the Lake Border and Valparaiso moraines is a till plain that was modifiedby waters of Lake Glenwood, which rose to an elevation of 195 meters.
Terwilliger (1952) proposes a sequence of glacial events to account for the features of Van Buren County. Each of the moraines is interpreted to have formed during readvances of the Lake Michigan lobe. He cites varved glaciolacustrine sediments exposed in western Allegan and Van Buren Counties that are stratigraphically between the Ganges and Saugatuck tills as evidence for a lake that occupied the area between the glacier and the Valparaiso moraine before its advance to the Lake Border moraine. 22 Recent work by Kehew et al. (2001) has shown that the Valparaiso moraine is comprised largely of deformed lacustrine sediments and contains a variety of landforms, including several drumlins. Kehew et al. argued that this does not represent a terminal position of the Lake Michigan lobe, but rather it is an upland capped by deposits primarily formed subglacially by the Lake Michigan lobe. The
Valparaiso moraine of Indiana may still be considered a terminal glacial position, as it may not correlate with the so-called "Valparaiso moraine" in southwest Michigan.
The Valparaiso moraine in Indiana more closely resembles the Kalamazoo moraine in
Michigan in topography and composition (Kehew, 2001; Fraser and Bleuer, 1991).
The origin of the Lake Border moraine was also called into question (Kehew et al.,
2002), in part because of a conspicuous lack of associated outwash. The ridge known as the Lake Border moraine may be a subglacial thrust feature.
In the mid 1980s, Monaghan and Larson demonstrated that till sheets associated with advances of the Lake Michigan and Saginaw lobes can be identified at the surface and at depth across southern Michigan and can be distinguished by the
composition of the clay mineralogy of the diamictons (Monaghan et al., 1986;
Monaghan and Larson, 1986). These authors identified three distinct diamicton
sheets of the Lake Michigan lobe. The earliest of these is the Glenn Shores till,
succeeded by the Ganges till, and later by the Saugatuck till (Figure 9). The Glenn
Shores till is overlain by stratified silt and sand containing organic material that was
dated at 37,150 to >48,000 yr B.P (Monaghan et al., 1986). The mean 7-10 angstrom
ratio for the Glenn Shores till is 1.22 :±().31,where 0.31 is the standard deviation. The 23
� � � � o w ,.,o !? !? 'b! .._'b 'b::.c " E ,,, ,Q ,"' " .._Q 'b � � "' .,, � ,,, ' ' � ,.'!, ,!' ,o, $ ·o:; ,::, d VJ
SAUGATUCK 1\Ll
Lo�e 0 15 M,cl119an kms 0 10 L__ ___J miles
Figure 9. Generalized stratigraphy of southwest Michigan (from Monaghan et al., 1986)
Ganges till has a mean 7 All0 A ratio of 0.85±0.18, and the Saugatuck till has a ratio
of 0.58±0.13. All three till units were identified at the shore of Lake Michigan near
Ganges, in Allegan County, Michigan. The lowest till was not found at any other
location. Diamicton sampled at the surface of the moraines in southwest Michigan
yielded a mean 7All0A ratio of about 0.62. From this Monaghan et al. conclude that
the Saugatuck till caps the moraines from the Lake Border system to the Kalamazoo
moraine. The Tekonsha moraine, immediately east of the Kalamazoo moraine,
yielded a ratio of 0.83±0.41. This was interpreted as being the surface expression of
the Ganges till. Dodson (1993) disagreed with this interpretation of the Tekonsha
moraine; he argued by means of elevation relationships, fabric analysis, lithic 24 indicators, as well as clay mineralogy for a Saginaw lobe origin for the Tekonsha moraine. Gardner (1997), Flint (1999), and Wong (2002) were able to distinguish diamicton units based on 7All0A ratios. Flint (1999) successfully correlated the informally named "Gray Marker till" in south-central Michigan with the Newberry till in Indiana. Wong (2002) was able to correlate tills- from the bluffs along Lake
Michigan in Allegan County as well as tills found within Allegan County with the
Ganges and Saugatuck tills characterized by Monaghan et al. (1986). CHAPTERII
METHODS
Field Methods
Boreholes were drilled by the Rotasonic drilling method, which provided a continuous core of 4 inches in diameter with minimal core loss during the drilling process. The Rotasonic drilling was performed by Prosonic, Inc., in 2002, and by
Boart Longyear, Inc., in 2001 and in 1999. The cores were describedin the field by members of the glacial research group at Western Michigan University, after which they were placed in boxes, which protect the cores during transportation and allows for organization of the cores for study and storage. Immediately following the
drilling, the boreholes were gamma ray logged. Natural gamma ray logs were run both descending as well as ascending at a velocity of 6 feet per minute with a time
constant of 10 seconds. Natural gamma radiation was recorded on logs with scales of
0 - 1000 counts per minute and 0 - 2000 counts per minute.
Laboratory Analysis
Textural Analysis Procedure
Laboratory analysis consisted of collecting samples at fixed intervals fromthe
cores. For the VB-01-09 core, the interval was 0.3 meters; the interval was 0.6 - 1
25 26 meter for the other cores. However, when a clay-rich unit was encountered, the sampling interval decreased to approximately once every meter for all of the cores.
Samples were chosen on the basis of the interval of interest as well as how well the sample represents the lithologic interval. The sampling interval was thereforeslightly modified according to the changes of lithologic units. After samples were collected, the textural analysis proceeded as follows, modified from Flint {1999), who demonstrated that this methodology closely approximated the methodology promulgated by ASTM (1970).
Samples of approximately 400 grams were taken from the cores. Weights of samples with a large percentage of gravel often were well above 40.Q._grams. For clay-rich samples, such as diamictons, wet sieving was necessary. The sample was placed in a 1000 ml beaker filled with deionized water for at least 8 hours. This slurry was washed through a #230 sieve fittedwith a pan in order to separate clay and silt from sand and gravel. A pan containing sand and gravel as well as a pan containing silt and clay were placed in an oven and allowed to dry. The sand fraction was sieved, as described below, whereas the sediment that passed through the #230 sieve was set aside as the clay and silt fraction.
The sand fraction from the wet sieving process was treated in the same manner as the samples that were not wet sieved. These samples were dried, if necessary, in an oven at 105° C for at least 24 hours. After the samples were dried they were gently disaggregated in a mortar with a rubber-tipped pestle. A porcelain pestle was carefully used on samples with a higher clay content to break the sample •
27 into small pieces that could be further broken down with a rubber-tipped pestle. Following this, the samples were placed in a series of sieves, consisting of the --#5, # 10, #20, #40, #80, # 100, and #230 forthe VB-01-09 core, and consisting of the #10,
#18, #35, #60, #120, and #230 for the other cores. Below the stack of sieves was a
bottom pan that would catch all sediment fineenough to pass through the #230 sieve.
The series of sieves was placed in a Roto-tap machine that agitated thesamples for5-
10 minutes. The amount of sediment retained in each sieve was weighed and
recorded. The sediment that passed through the #230 sieve was considered to be silt
and clay and was added to the silt and clay separated during the wet sieving
procedure for clay-rich samples. The silt was separated from the clay by means of
settling velocities, as described below.
In order to determine the weights of the silt and clay fraction, these two
fractions must be separated. This was accomplished by the principles of Stokes' tcLaw. Stokes' Law states that silt-sized particles will settle from a height of IQ_ cm
within two hours a!_2Q° C, while particles smaller than silt-sized (i.e. clay-sized
particles) will remain in suspension (Boggs, 1995).
To accomplish this separation, the clay and silt fractionwas placed in a beaker
and a solution of 0_1% sodium hexa-metaphosphate was added until the total volume
of sediment and solution was approximately 700 ml, which corresponds to a height of
1Q sm. This s� was agitated with an ultrasonic stirrer for approximately 9
minutes. The slurry was allowed to settle fortwo hours. The supernatantcontaining
suspended clay-sized particles was decanted into a pan of known weight and placed 28 in an oven to dry. The silt that had settled to the bottom of thebeaker was also placed in a pan of known weight and transferred to an oven to dry. After the samples were dry, they were weighed and recorded as weights of silt and clay.
This procedure of separating silts and clays was modified slightly for diamicton samples as well as forsome other samples forthe purpose of making slides for X-ray diffraction. The clay was separated fromthe silt after two hours, as in the above procedure, except the clay was poured into another I_Q.00 ml beaker, instead of into a pan. This beaker was left undisturbed for at least t hours in order to let particles smaller than � settle- to the bottom.- Slides for X- y diffraction- were made at this point, and the clay slurry was transferred to a pan and dried as in the above procedure. Because only a small amount (~ 10 ml) was used to make each clay slide, the total clay weight was es�ntially unaffected by this procedure. The silt portion of the sample was treated exactly as previously described.
X-ray Diffractionof Clay Minerals
The mineralogy of clays is most easily studied through X-ray diffraction
(XRD). XRD works because of both the size and structureof clay minerals as well as the size of X-ray beams and their wave-like properties. Clays are sheet-like crystals ,---. - that are orders of magnitude larger in the horizontal direction than in the vertical direction. The spacing between planes of atoms in the ve�al dir�tion, known as the basal spacing, or d-spacing, is small (~5-20 angstroms)- and is of a comparable ---.- ,-/ size to X-ray beams (1.54 angstroms from a CuK.a source). The d-spacing is also a 29 characteristic property of clay mineral groups (Table 1 ). When clay crystallites are oriented with their horizontal planes parallel to the slide on which they are mounted
Table 1
X-ray diffractionproperties of select clay minerals (adapted fromMoore and Reynolds, 1997)
Clay mineral Reflector plane d-spacing 029
Chlorite 001 14.lA 6.3 002 1.1A 12.5
003 4.75A 18.8 Kaolinite 001 7.lA 12.5 002 3.5A 24.9
Vermiculite 001 14.4A 6.0
° 001 (>300 C) 10A 8.8
Illite 001 10. lA 8.8 002 5A 17.9
X-ray beams that are diffracteddue to a specific------d-spacing-- are intensifiedand are able to be viewed above backgroundradiation (Velde, 1992).
X-ray diffractiontakes advantage of the geometric relationship between the d spacing and the angle of incidence between the X-ray beam and the sample as the 30 sample is rotated through various degrees, 0, while the detector is rotated through various degrees, 20. Constructive interference of X-ray beams results when the angle of incidence, 0, of the X-ray beam creates the following relationship between the wavelength of the X-ray beam, y, and the d-spacing, d, as first worked out by Bragg
(1912):
Equation 1. The Bragg Equation
2dsin0 = ny
wheren = a whole number
Through this equation the d-spacing of the clay minerals can be deduced by the angles at which diffraction peaks occur. The samples are scanned from 2 to 20 degrees20 (the detector rotates 2 degrees forevery degree that the sample rotates). A diffractogram is produced with degrees 20 on the x axis and intensity, measured in counts per second (CPS), on the y axis (Figure 10). The diffractogram consists of two components: white radiation and diffraction peaks. White radiation appears as a smooth curve with its highest intensity near 2° 20, after which it decreases sharply.
This curve depends on the voltage used to accelerate electrons through the vacuum within the tube and is produced by the rapid deceleration of electrons within the tube as they encounter strong electrical fields in the target material (Moore and Reynolds,
1989). Superimposed on the white radiation are diffraction peaks. These are the result of constructive interference as explained above. Peak intensity depends on the number of clay crystals present, as well as other factors, such as the degree of 31
VB-01-09AH
2000
1800
1600
1400
1200
800
600
400
200
0 2 4 6 8 10 12 14 16 18 20 degrees20
Figure 10. Example of an X-ray diffractogram crystallinity, the presence of polymorphs, and the overlap of diffraction from two or more difference clay types. An example of this would be the diffraction peak produced at approximately 6° 20, which could be produced by chlorite (001) or vermiculite (001). Because of this overlap, it is not possible to discern through this procedure exactly which clay minerals are present; thus the procedure is considered to be semi-qualitative. A common procedure utilized in clay mineral analysis is the comparison of the 7-angstrom peak height to the I 0-angstrom peak height, known as the 7All OA ratio. This is assumed to compare the relative amounts of kaolinite to 32 illite,- which several researchers have used to correlate- diamicton- units in the su�ce throughout Michigan (e.g. Monaghan and Larson, 1986; Monaghan et al.,
1986; Gardner, 1997; Flint, 1999; Wong, 2002).
The procedure for making oriented clay mounts for XRD as outlined by
Moore and Reynolds (1989) was slightly modified.· Approximately 10 ml was pipetted from the supernatant after the 8-hour settling time, assuring that particles greater than 2 µm settled to the bottom and would not become part of the mount.
Slides were allowed to air dry as long as necessary, which usually took one day. X ray diffraction was performed in a Rigaku® XRD unit that was run at the settings shown in Table 2. Each samplewas placed into the X-ray chamber, which wassealed once the sample was in place. The settings for v�tage and amperage were slowly increased to 35 kV and 20 and each sample was scanned from 2 to 20° --- mA, -- --20. Following this procedure, samples were placed in a furnace and heated to �15° C for one hour. This causes the vermiculite structure to collapse from 4A to 1 0A. The slides were again scanned as described above; 14A peaks that occur in this scan are fromthe presence of chlorite.
Computer �ysis
Processing of GammaRay Logs
® Gamma ray logs were digitized using Rockworks softwareand a digitizing puck. The file was exported as an .xis fileand imported into MicrosoftExcel ®, 33 Table 2
X-ray DiffractometerSettings
Volts 35 kV Amps 2OmA Receiving slit 10 Soller slit 0.30 Anti-scatter slit 0.8° Goniometer speed 2° 20 per minute Proportional kV 1.5 Range lK Time constant 1 second
where an x-y chart was generated that had depth on the y axis and counts on the x axis. Digitized wire-line logs are capable of being imported into Logplot® where a composite log fromseveral data sources can be produced.
Processing of Sieve Data
A spreadsheet was created using Microsoft Excel® to process the textural analysis data. Values for weights retained by each- sieve were converted to percentages of the total sample. Cumulative percentages of weights were also calculated. In addition to this, th�l was subtracted from the total weight, and normalized percentagesof -sand, -silt, and clay were calculated. Statistical parameters, including mean grain-- size, sorting,-- skewness,-- and kurtosis,- were calculated by the method of moments (Krumbein and Pettijohn, 1938) using the percentage data in the spreadsheet. The equations to calculate these parameters are as follows: 34
Equation 2. Mean (1 st moment)
X = Lfin n
Equation 3. Standard deviation (2nd moment)
2 a= ✓Lf(m-x) 100
rd Equation 4. Skewness (3 moment)
3 Lf(m-x) Sk= 100a3
Equation 5. Kurtosis (4th moment)
4 Lf(m-x) K= 100a4
where f is the weight percent in each grain-size present, m is the midpoint of each grain size grade in phi values, and n is the total number in the sample, which is I 00 when/is in percent.
Processing of XRD Data
Files generated during X-ray diffraction were saved onto a floppy disc and
® opened up with Microsoft Excel in order to generate a diffractogram.
Diffractograms were saved and printed. A baseline was drawn on the printed diffractograms by interpolating the white radiation response through the diffraction 35 peaks, where the white radiation is not displayed on the graph. Both 7A and 1 OA peak heights were measured with a ruler to the nearest 1 mm, since there was an estimated 0.5 mm of possible error associated with the interpolated baseline. The ratios of these peaks were calculated and tabulated. The 14A peak heights on diffractograms from the air-dried- and the heated samples were compared to distinguish chlorite fromvenniculite.
Postprocessingof Data
For each core, a composite display incorporating textural analysis, XRD, and gamma ray log data was generate in Logplot®. Each core contains a lithologic description of the core accompanied by a brief description of the sediment. Aligned with the lithologic description of the core is each of the following: gamma ray log
( continuous curve); weight percent of each sieve (histogram foreach sample); percent sand, silt, and clay (histogram for each sample); mean, sorting, skewness, and kurtosis (curve connecting values for each sample); and numerical values of 7All OA ratios, where they are available. CHAPT ERIII
RESULTS
The results of textural, X-ray diffi'action, and stratigraphic analysis are presented below. Student t-tests were also calculated comparing 7A/10A peak-height ratios between diamicton units. Five of the cores contained at least one diamicton unit, while one core, VB-01-07, did not contain any diamicton units. Glaciofluvial outwash and glaciolacustrine deposits dominated most of the cores. Since each of the cares was drilled on a different glacial landfonn, the ground elevation and the interpreted Jandfonn must be considered when examining each core and when attempting to correlate units among the cores. Cores will at first be discussed individually, afterwhich they will be discussed collectively.
Individual Core Descriptions
VB-99-03
VB-99-03 was drilled on the Kendall moraine in northeastern Van Buren
County, at an elevation of approximately 250 meters above sea level and to a total depth of 38 meters. A composite log containing a core description, gamma-ray log, distribution of grain sizes, textural statistics, and 7AllOA peak-height ratios is given in Figure 11. This core is divided into 8 units; the average textural results,
36 37 VB-99-03
%coarse sand 1 -mean %medium sand %sand Elevation lithology Description Gamma ray log 2 -sorting [7/10 ratio Depth %fine sand � %silt (m) cpm 3 -skewness ( ) %very fine sand %clay (m) %silt 4 -kurtosis � %.,,-,clay 0 1000 0% 100% 0% 100% 1 2 3 4
DIAMICTON: 0 l.lnl1 n/a
FN'SAIIO: Uni2
245 -5 SANDAND GRAVEL: Uni3
SLTY SA/ID: l.lnl 4 240 -10 DIAMICTON: 0.618 UnilS n-3
SANDAND GRAVEL: 235 Uni6 -15
230 -20
225 -25
220 -30
FN:SAIIO: Uni 7
215 -35
SAND: UniB
Figure 11. Composite log for VB-99-03 38 presented in percentages of sand, silt, and clay, are shown in Table 3. A sandy, r ddish-brown, cJast-rich diamicton caps the surface at this location. This unit produces a relatively high gammc1=ray response and occupies the top..2 meters of the core. The matrix of this diamicton is �1t.sand, 17.9%-- silt, and 5.7%-- clay (Figure 12). Only one sample was analyzed from this unit, and although a slide forXRD was prepared, no 7 All0A ratio could be obtained because of weathering of the clay minerals near the surface. Below the diamicton is a 3-meter unit of fine sand, 1.5 meters-- of which are very well sorted. A coarser unit comprises 3 meters of sand and gravel lies below the fine sand. This unit fines downward and is followed by a lacustrine unit of laminated silt, with small amounts of fine sand and clay. The average texture of this unit is 0.1 % gravel, 57.6%- sand, 38.5%- silt, and 3.8%-- clay. This unit is very s!!!::!!£h at the top and coarsens downward, with finesand becoming more abundant with depth. Directly below the lacustrine unit is a light-tan, sandy diamicton that is 2.5 meters thick. Threesamples were taken from the diamicton, and the average texture of the matrix is 46.0% sand, 46.3% silt, and 7.7% clay. Individual matrix texturesare plotted in a ternarydiagram in Figure 13. A mean 7All0A ratio of
0.618 was calculated from the three samples (Figure 14). There is a high gamma-ray signal produced by the la�trine and diamicton units. Below the diamicton is a thick unit of coarse sand and gravel that extends from 13 meters to a depth of 31 meters below the surface. Although no core was recovered between 14 and 17 meters, the gamma-ray log shows no significant change in this interval; thus it can be assumed to be part of the sand and gravel unit that is above and below this missing interval. Table 3
Average texture by unit forVB-99-03
Contains 8 units;48 samoles; 38 meters
# of samples depth (m) thickness %sand o/o silt %clay clay samoles mean7/10 unit 1 diamicton 1 0-2.1 2.1 76.4 17. 9 5.7 unit2 fine sand 4 2.1-5.2 3.1 94.7 4.6 0.7 unit3 sand and aravel 5 5.2-8.2 3.0 89.6 9.1 1.3 unit4 vervfine sand and silt 4 8.2-10.7 2.5 57.7 38.5 3.8 units diamicton 3 10.7-13.1 2.4 46.0 46.3 7.7 3 0.618 unit& coarse sand and aravel 21 13.1-31.1 18.0 88.5 11.0 0.5 unit7 fine sand 9 31.1-37.2 6.1 78.9 20.8 0.4 unit8 medium sand 1 37.2-38 0.8 86.1 13.2 0.7
'°w J 40
CB(
Figure 12. Matrix texture for samples ofVB-99-03 upper diamicton
Although the average texture of the unit is 21% gravel, � .4% sand, 9 .1% silt, and
0.4% clay, it. is highly variable (see Figure 11 (composite log)). Medium and coarse sand dominate the upper portion of this unit, whereas gravel dominates downward from around 27 meters in depth. At the point where� becomes dominant, there is a one-meter section with abundant large clasts (~5 cm). Below this the most abundant clast size ranges from1 cm to 2.5 cm in diameter. Unit 7, below the coarse sand and gravel unit, is a unit of well-sorted fine sand that extends from 31 to }__7 41 meters below the surface. Its average texture is 0.0% gravel, 78.9% sand, 20.8% silt, and 0.�% clay. The core ends in approximately one meter of medium to coarse sand, which contains 8.2% gravel,79.0% sand, 12.1 %�It, and o:7% clay. ------_. ----
Figure 13. Matrix texture forsamples ofVB-99-03 lower diamicton mean=0.618 3,------�------�
2t------;------.j
C GI :::,
o------� 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.1 1.2 1.3 1.4 7/10 peak-heightratio
Figure 14. Histogram of 7All OA ratios forVB-99-03 lower diamicton
..,::.. N 43
VB-01-07
VB-01-07 was drilled on an area mapped as an outwash channel on the property of Paw Paw High School, in the town of Paw Paw, Michigan. This core differs fromthe other cores by its location in a topographic low. The ground elevation is 238 meters above sea level, and the total depth of the core is 41 meters. The core contains glaciofl�l deposits of sand and gravel as well as fine-grained glaciolacustrine deposits. No diamicton units are present. The composite log forVB-
01-07 is given in Figure 15, and the mean t�percentages for each unit are given ' in Table 4. The core begins with 10.5 meters of poorly sorted coarse sand and gravel, with an average texture of27.1% gravel, 68.4% sand, 3.9% silt, and 0.5% clay. Units
2 through 7 (10.5 - 32.5 meters in depth) can all be considered lacustrine deposits.
Unit 2, a sandy silt, extends from 10.5 to 18 meters in depth. Near the top ofthis unit are several cobbles with calcite concretions within the silt. This unit of the lacustrine sequence is dominated by fine sand, with a total sand percentage of �5.7%. Directly below this unit is a th�ens ofgravel and coarse sand, about 1.5 meters in thickness.
Below this gravel lens are alternating units of clayey silt and silty sand, all of which show laminations. Unit 4, a cla ey silt unit, is gray- in color and is very compact. This unit comprises 0.0% gravel, 7.6% sand, 82.4% silt, and 9.9% clay; it is 2 meters in thickness and it grades into a 3-meter thick unit of silty sand, with a mean texture of
0.0% gravel, 81.6% sand, most of which is fine sand, 17.9% silt, and 0.5% clay.
There is a color change at the top of Unit 6 from grayto tan. This unit is another 44
VB-01-07
% coarse sand 1 - mean % medium sand %sand Elevation Lithology Description Gamma ray log 2 -sorting 17/10 ratio Depth % finesand �% silt (m) (cpm 3 -skewness ) % very fine sand % clay (m) % silt 4 . kurtosis �-•-''ll, clay 0 1000 0% 100% 0% 100% 1 2 3 4
SAJIO AJIO 0 GRAva: Uni11 235
-5
230
-10 SAJIOY SILT: Uni12 225
-15
220 GRAVEL: Uni13 1.357 CLAYEY -20 SLT: l.nl:4 n=3 SLTY SAJ\O: 215 Unit 5
CLAYEY 0.752 -25 SLT: l.nt 6 n-3
210 SLTY SAJ\O: Uni17 -30
205 SAJIO AJIO UniGRAVEL: 8 -35
-40
Figure 15. Composite log for VB-01-07 Table 4
Average texture by unit forVB-01-07
Contains 8 units; 56 samples, 41 #of depth meters samples thickness %sand % silt %clay (m) clay samples mean 7/10 unit 1 sand and aravel 13 0-10.7 10.7 94 5.3 0.7 unlt2 silty sand 12 10.7-18.0 7.3 70.4 28.1 1.5 unit3 �ravel 1 18.0-19.5 1.5 97.3 2.3 0.4 unit4 ¢1ayey silt 3 19.5-21.3 1.8 7.6 82.4 10 3 1.357 units siltysand 4 21.3-24.7 3.4 81.6 17.9. 0.5 unit& clavev silt 3 24.7-27.5 2.8 8.8 82.8 8.4 3. 0.752 unit7 fineto siltysand 8 27.5-32.6 5.1 81.5 17.4 1.1 unit 8 sand and gravel 12 32.6-41 8.4 90.7 8.2 1.1
Vo""' 46 dense clayey silt, about 2.7 meters in thickness with a similar texture to Unit 4. Three slides from each unit were made from the clay fraction of Units 4 and � for XRD
analysis. The mean 7A/10A ratio from Unit 4 is 1.357 and from Unit 6 is 0.752.
Samples fromthese two units are plotted in Figure 16 and Figure 17. Unit 7, slightly
coarser in texture, is a silty sand that is dominated by medium to fine sand. Its mean texture is 6.5%- �l, 75.8%- sand, 16.7%- silt, and 1.0%- clay. The gamma-ray signal for this core is strongest in Units 4, 6, and 7. The lowest unit in this core is an 8.2- meter thick layer of sand and gravel, with a mean texture of 48.4%------gravel, 46.9%- sand, 4.2% silt, and 0.5% clay. The gravelis composed of clasts primarily less than 1 � -- - cm in diameter in the upper portion of this unit. There are two significant color
changes within this unit. At 33.5 meters in total depth the color changes fromgray to
br�wn and then to gray at 38 meters. Accompanying the firstcolor change is a change
in energy as represented in the gravel size. The gravel clasts increase to 5 - 8 cm in .------� diameter at the point where the color changes to brown. Clasts continue to be as large
as 5 - 8 cm throughout the remainder of this layer.
VB-01-09
Core VB-01-09 was drilled near the crest of a drumlin located on the upland
surface that has been traditionally mapped as the Valparaiso moraine. The top
elevation of this core is 250 meters above sea level, andthe core extends 49 meters in
depth. Samples were taken from this core at approximately 0.3-meter intervals mean 1.36 3
2..__------..a...,
1-1------�
0 -+------,------,----,------.-----.------,-----.----,------,----,----,---- 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 7/10 peak-heightratio
Figure 16. Histogram of 7A/10Aratios forVB-01-07 lacustrine Unit 4
� -...J mean = 0.732 3-.------,
2+------
1+------
0 -+----.----.----,-----,------,---,-- 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.1 1.2 1.3 1.4 7/10 A peak-heightratio Figure 17. Histogram of 7All 0A ratios forVB-01-07 lacustrine Unit 6
-"'- 00 49 throughout most of the core. Within consolidated diamicton units the sampling interval ranged from 0.6 - 1.2 meters. Slides forXRD weremade from the upper and lower diamicton units as well as from the middle lacustrine unit. The composite log forVB-01-09 is shown in Figure18, and the mean textural data are given in Table 5. There is a 6.4-meter thick diamicton layer at the top of the core. This diamicton is brown at the surface but becomes grayat about 2.4 meters in depth, possibly because of the depth of oxidation. This unit is a diamicton containing clasts mostly less than 3 cm in diameter, with a mean matrix texture of 57.8% sand, 32.4% silt, and 9.8% clay.
Textures from the 11 samples of this diamicton are plotted in Figure 19. X-ray diffraction results indicate a mean 7All OA ratio of 0.589 (Figure 20). The change in color from brown to gray coincides with a change in 7 All oA ratios from 0.3 in the brown diamicton to 0.8 below the color change. Near the base of the diamicton, however, 7A/10A ratios are 0.3. The change in these values is the result of change in the intensity of the 7 A peak. This peak is much higher in samples from the middle part of the diamicton than it is in samples near the top and the base of the diamicton.
Directly below this surface diamicton is a 1.2-meter unit of sand and gravel, with a mean texture of 51.8% gravel, 41.1 % sand, 6.2% silt, and 0.8% clay. This unit, as well as Unit 4, produces a weaker gamma-ray signal than the rest of the core. This thin unit of outwash fines into a very thick sequence of lacustrine sediments, including Units 3 through 8 (7.6- 38.4 meters in depth). The sediments that comprise this 30-meter section of the core alternate between sandy units (Units 4 and 6) and predominantly silty units (Units 3, 5, and 7). Calcite cemented grainsare common in 50
VB-01-09
'JI, gravel 'JI, coaisesand 1-mean 'JI, medium sand Elevation Lithology Description Gamma ray log 2 - sorting 17110 ratio Depth 'JI,fine sand 'JI,silt ,-I (m) (cpm) 3-skewness (m) ,- 'JI,very fine sand %day 'JI,silt �--·· 4 - kurtosis I %day 0 1000 0% 100% 0% 100% 1 2 3 4
Dl,t,J,ICTON: 0 lri1
n - 11 -5
SAN'.) //NJ GRAVEL: lri2 SAN)YSLT: -10 lri3 SAN'.):lri 4 SAN'.lYSL T: lri5 -15
-20 SLTYSAN): lri6
-25
-:ll
SAN'.lYSL T: lri7 -35
SAN): lri 8
Dl,t,J,ICTON: O.!M4 lri9 -40 n-7 SAN'.) //NJ GRAVEL: lri10 -45 SAN'.):lri 11
Figure 18. Composite log forVB-01-09 Table 5
Average texture by unit forVB-01-09
Contains 11 units;142 samples; 49 meters
#of samples depth (m) thickness %sand % silt %clay clay samples mean7/10 unit 1 diamicton 8 0-6.4 6.4 57.8 32.4 9.8 11 0.589 unlt2 Qravel and sand 4 6.4-7.6 1.2 92.9 6.2 0.8 4 0.562 unit3 sandy silt 3 7.6-8.5 0.9 39.5 58.7 1.8 3 0.413 unit4 sand 6 8.5-10.4 1.9 89.4 9.9 0.7 2 0.469 units sandy silt 34 10.4-20.4 10.0 52.6 44.9 2.6 6 0.57 unlt6 siltv sand 42 20.4-33.2 12.8 85.0 13.9 1.1 unlt7 sandy silt 11 33.2-36.6 3.4 51.7 46.0 2.3 unite medium sand 6 36.6-38.4 1.8 85.6 13.5 0.9 unit9 diamicton 7 38.4-41.8 3.4 47.4 45.6 7.0 8 0.944 unit 10 !gravel and sand 9 41.8-45.1 3.3 91.6 7.3 1.1 unit11 sand 12 45.1-49 3.9 95.6 3.7 0.6
VI- 52
CB{
Figure 19. Matrix texture forsamples ofVB-01-09 upperdiamicton
the upper part of this sequence. Laminations also occur throughout these units.
Fifteen slides were made :from Units 2 through 5 forX-ray diffractionand result in a mean 7A/10Aratio of 0.48 (Figure 21). The lower 2 meters of this sequence is a unit of well-sorted fine sand, with a mean texture of 0.2% gravel, 85.4% sand, 13.5% silt, and 0.9% clay. Of the 85.4% sand fraction, more than 90% of this is very fine sand.
Unit 9 is a lower silty, matrix-supported gray diamicton unit that produces a very strong gamma-ray signal and that extends from38.4 - 41.8 meters below the surface.
The mean texture of this diamicton is 47.4% sand, 45.6% silt, and 7.0% clay. The mean=0.569 5�------�
4-+------
3+------•..II 41 ;. �• � 2+------�
0-+------� 0.1 02 0.3 0.4 0.5 0.6 0.7 0.8 0.9 11 12 13 14 7/ 10 A peak-height ratio
Figure 20. Histogram of 7A/10Aratios forVB-01-09 upper diamicton
VI w mean-0.48 1
6+------
5+------
c�4+------ :I• 13+------
2+------
0 +------0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.1 1.2 1.3 1.4 7/10 A peak-height ratio
Figure 21. Histogram of7All0A ratios forVB-01-09 lacustrine unit
Vl .f:. 55 textures for all of the samples from this diamicton are plotted in Figure 22. The mean
7All0A ratio is 0.944 (Figure 23). Below the diamicton is an outwash sequence, with
3.4 meters of gravel and coarse to medium sand fining downward to predominantly medium sand for3.6 meters.
Figure 22. Matrixtexture forsamples of VB-01-09 lower diamicton mean=0.944 7
6
5
�4 -[3 2
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.1 1.2 1.3 1.4 7/10 peak-heightratios
Figure 23. Histogram of 7All0A ratios for VB-01-09 lower diamicton
°'V, 57 VB-02-01
Three cores were drilled during the 2002 drilling season. The first of these,
VB-02-01, was drilled on an upland area in southwest Van Buren County that has been mapped as an ice-marginal or subglacial landform (Kehew et al., 2002). The elevation of the core is 230 meters above sea level, and the core extends 33.5 meters in depth. The composite log for this core is given in Figure 24, and the mean textural results are given in Table 6. This core contains a thin surface diamicton, a thick sequence of glaciofluvial deposits, a lower diamicton, and a lower s�quence of glaciofluvial deposits. The upper and lower diamictons produce a strong gamma-ray signal, whereas the sediments between these diamictons produce only a weak signal.
The upper diamicton is brown in color and extends to a depth of 1.5 meters. The texture of the matrix, plotted in Figure 25, is 52.8% sand, 38.7% silt, and 8.6% clay.
Only one sample was taken from this unit and weathering of clays prevented a
7All OA ratio from being obtained. The diamicton rests atop 1.2 meters of medium sand. This unit coarsens downward into Units 3 and 4, which are units ofgravel and sand, ranging from 26.9% gravel and 68.8% sand in Unit 3, in which most of the gravel is approximately 1 cm in diameter with some clasts as large as 5 cm, to Unit 4, which has a mean texture of2.9% gravel and 91.6% sand, with minor amounts ofsilt and clay. The coarse sediments extend to approximately 9.5 meters in depth, after which there is an extensive unit ofprimarily medium and fine sand for 9 meters. This section of the core could be lacustrine in origin, although no laminations were found in the core. Unit 6, directly below the medium and fine sand unit, is a unit 58 VB-02-01
% coarse sand 1. mean 'I, medium sand %sand Elevation Lithology Description Gamma ray log 2 . sorting 7/10 ratio Depth % fine sand � % slit (m) m 3 -skewness (cp ) % veryfine sand % clay (m) %silt 4 . kurtosis �-•-'% clay 0 1000 0% 100% 0'1, 100% 1 2 3 4
DWACTON: 0 Uni1 n/a SN-O:Uni2
SAt-0 At-0 GRAVEL Unit 3 -5 SAt-0 At-0 225 GRAVEL Uni 4
SN-0: Uni 5 -10
220
-15
215
SAt-0At-0 GRAYa: Uni6 -20 DIAMICTON: 210 Uni 7
n=8 -25
205 SAt-0:Uni 8
-30
200
Figure 24. Composite log for VB-02-0 I Table 6
Average texture by unit forVB-02-01
Contains8 units;45 samples; 33.5 meters
#of samples depth (m) thickness %sand % silt %clay clay samples mean7/10 unit 1 diamicton 1 0-1.5 1.5 52.8 38.7 8.6 unit2 medium sand 2 1.5-2.7 1.2 96.5 2.1 1.3 unit3 gravel and sand 5 2.7-5.8 3.1 94.3 4.9 0.8 unit4 sand and aravel 5 5.8-9.5 3.7 94.4 4.5 1.1 units medium sand 11 9.5-18.6 9.1 96.6 2.8 0.6 unit6 sand and gravel 3 18.6-20.4 1.8 94.9 4.5 0.6 unit7 diamicton 10 20.4-26.5 6.1 66.9 30.1 3.0 8 0.442 unit8 sand (fining downward) 8 26.5-33.5 7.0 99.2 0.6 0.2
VI l,O 60
Figure 25. Matrix texture forsamples ofVB-02-01 upper diamicton representing a higher energy environment, with a larger portion of coarse sand and gravel. This coarse layer is only 1.8 meters in thickness, and it lies directly above a lower diamicton unit. The diamicton, 6 meters in thickness, is clast-rich with a predominantly sand matrix. The matrix textures are plotted in Figure 26, with a mean matrix texture of 66.9% sand, 30.1 % silt, and 3.0% clay. X-ray diffractionwas run on eight slides taken from this unit (Figure 27) resulting in a mean 7 All 0A ratio of
0.442. The core extends through 7 meters of outwash below the diamicton, with 61
Figure 26. Matrix texture forsamples of VB-02-01 lower diamicton coarser deposits at the top of the unit, including gravel with clasts up to 4 cm in diameter, finingdownward to medium and fine sand at the bottom of the core.
VB-02-02
The second core of the 2002 drilling season, VB-02-02, was drilled on an area mapped as a glaciolacustrine plain (Kehew et al., 2002) at an elevation of 204 meters above sea level, located approximately 3 kilometers east of the crest of the Lake
Border moraine. The core extends to a depth of 29 meters and is composed mean=0.397
5.------,------,
4+------
3
12-----
1+------
0+---�--� 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.1 1.2 1.3 1.4 7/10 A peak-height ratio
Fi_gure 27. Histogramof 7All0A ratios forVB-02-01 lower diamicton
0\ N 63 primarily of lacustrine deposits. The surface diamicton produces a strong gamma-ray signal. Below this the signalis weak but gradually becomes stronger as the sediment becomes siltier. The lower diamicton also produces a fairly strong signal. The composite log for the core is given in Figure 28, and the mean textural data are given in Table 7.
There is a thin, brown, clay and silt-rich unit at the surface that could be either of lacustrine or glacial origin, or could be the result of surficial weathering (Kehew, personal communication). Evidence to support a lacustrine origin include faint structures that could be interpreted as laminations. These structures are visible in less than 20 cm of the sample. The sediments in the unit, however, are unsorted, ranging from clay and silt-sized particles to sand and gravel. Although it is difficult to ascertain whether the clasts have any glacial characteristics, the unsorted nature of the sediment is strong support for a glacial diamicton interpretation of the unit. Thin, unsorted surface sediments, however, could be produced by weathering, and could easily be mistaken for a thin, surface glacial diamicton (Kehew, personal communication). Two samples yield a mean texture of 5.0% gravel, 40.0% sand,
46.2% silt, and 8.8% clay. The texture for the matrix of this unit is shown in Figure
29. Although 5% of the sample is gravel, the clasts are less than 2 cm in diameter.
Due to surface weathering, slides made from this unit produce no clear diffraction peaks that could be useful forcorrelation. Units 2 through 7 can be grouped together as a lacustrine sequence. Unit 2, 3 meters in thickness, consists of medium sand that fines downward into Unit 3. Unit 3 is a layer of laminated silt with a 64 VB-02-02
% coarse sand 1 -mean % medium sand %sand Elevation Lithology Description Gamma ray log 2 -sorting 7/10 ratio Depth % fine sand � % silt (m) pm 3 -skewness (c ) % very fine sand % day (m) % sih 4 - kurtosis � %··~·· day 0 1000 0% 100% 0% 100% 1 2 3 4
DIAMICTON: 0 Unit1 n/a
SAND:l.. SAND: l..<1i4 195 -10 190 -15 SAND AND GRAVEL: Unit5 SANDYSLT: Unit6 185 -20 180 CLAYEY -25 SLT: Unil7 DIAMICTON: 0.812 Unit8 n=3 Figure 28. Composite log for VB-02-02 Table 7 Average texture by unit forVB-02-02 Contains8 units;40 samples; 29 meters #of samples depth (m) thickness %sand % silt %clay clay samples mean 7/10 unit 1 diamicton 2 0-3.0 3.0 45.0 46.2 8.8 unit2 fine sand 4 3.0-5.8 2.8 70.6 28.4 1.0 unit3 silt with Qravel 3 5.8-7.6 2.2 56.2 41.9 2.0 unit4 fine to vervfine sand 12 7.6-16.2 9.4 98.2 1.6 0.1 units sand and Qravel 2 16.2-17.4 1.2 98.0 1.4 0.6 unit& fine sand and silt 12 17.4-25.0 7.6 77.9 21.5 0.6 unit7 clay and silt 2 25.0-26.5 1.5 6.7 74.3 19.0 unit8 diamicton 3 26.5-29 2.5 38.5 54.4 7.1 3. 0.812 O'I V, 66 Figure 29. Matrix texture forsamples ofVB-02-02 upper diamicton significant percentage of gravel-sized dropstones. The mean texture of this unit is 25.8% gravel, 30.4% (very fine) sand, 41.9% silt, and 1.0% clay. Unit 4 differs from Unit 3 by having no gravel content, and very little silt as well. The predominating texture of Unit 4 is fineto very fine sand, which constitutes over 90% of the material. The sediments gradually coarsen between 12 and 15 meters in depth. This is evident in the decreasing percentage of very fine sand and with the increase in the percentage of coarse sand. At 16 meters there is a 1.2-meter lens of coarse sand 67 and gravel(Unit 5), below which the sediment becomes much finer, primarily silt and very fine sand, to a depth of 25 meters. At 25 meters there is a thin (~ 1.5 meter) layer of consolidated, laminated, gray silt and clay, Unit 7. Directly below this is a lower diamicton that extends 2.4 meters to the bottom of the core. This is a dense, clast-rich gray diamicton, with a mean matrix texture of 38.5% sand, 54.4% silt, and 7.1% clay. Textures for each of the three samples from this unit are plotted in Figure 30. The mean 7Al10A ratio is 0.812 (Figure 31). CBf Figure 30. Matrix texturefor VB-02-02 lower diamicton mean 0.812 3 2+------'------t •.."' 0+----�------,----�---�---�--�- 0.1 02 0.3 0.4 0.5 0.6 0.7 0.8 0.9 11 12 13 14 7/'ll pNk-hllghl ratio Figure 31. Histogram of 7A!I0A ratios forVB-02-02 lower diamicton 0\ 00 69 VB-02-03 This core was drilled on the crest of the Lake Border moraine at an elevation of 215 meters above sea level, near the town of Covert. It differs radically from the previously discussed five cores as it is composed almost entirely of diamicton. The composite log for VB-02-03 is given in Figure 32, and the mean textural data are shown in Table 8. The gamma-ray signal from this borehole is strong, indicating the abundance of fine-grained sediments. The signal also shows variability in the texture of the diamicton and shows thin layers of sand near the bottom of the core. The core is divided into six units based on changes in texture. The first unit represents the top 26 meters of the core and is a gray diamicton. The diamicton is tan near the surface and is largely mottled to a depth of around 6 meters, at which point the color changes to gray. There are a few small pebbles in the upper portion of this unit, with pebbles becoming larger in size with depth. There are cobbles as large as 5 - 8 cm in diameter at approximately 15 meters in depth. The matrixof this diamicton is relatively constant, being composed largely of silt and clay throughout its 26-meter thickness. The mean matrix texture is 32.5% sand, 55.4% silt, and 12.1% clay. Figure 33 is a plot of matrix textures fromthe 24 samples taken fromthis diamicton. This core provided a unique opportunity to study clay mineralogy, as ascertained from 7AII0A peak-height ratios, as a function of depth. The mean ratio for this diamicton is 0.605 (Figure 34). No apparent trend could be found between 7A/10A peak-height ratios and depth, but ratios showed great variability in peak height ratio at a single location (Figure 35). There is a strong correlation between 70 VB-02-03 %coarse sand 1 - mean %sand Elevation Lithology Description Gamma ray log % medium sand 2 - sorting 7/10 ratio Depth %fine sand �%silt m) cpm 3 -skewness ( ( ) %very fine sand %clay (m) %silt 4 - kurtosis � %.,,�,,clay 1000 0% 100% 0% 100% 1 2 3 4 215 210 205 200 195 -25 100 SANDY SILT: Unit2 CLAYEY SLT: Uni:3 SAND: Uni:4 -30 CLAYEY 185 SILT: Uni:5 Dw.tCTOllt Uni6 Figure 32. Composite log for VB-02-03 Table 8 Average texture by unit forVB-02-03 Contains 6 units;35 samples; 32 meters #of samples depth (m) thickness %sand %silt %clay clay samples mean 7/10 unit 1 diamicton 24 0-26.2 26.2 32.5 55.4 12.1 24 0.605 unit2 medium sand and silt 1 26.2-26.8 0.6 68.7 29.1 2.2 1 0.765 unit3 clayev silt 3 26.8-28.7 1.9 32.0 54.1 14.0 3 0.651 unit4 medium sand 2 28.7-29.4 0.7 97.0 2.7 0.3 2 0.393 units clayey silt 1 29.4-29.9 0.5 0.3 59.4 40.3 1 0.985 unit& diamicton 4 29.9-32 2.1 26.1 65.0 8.9 4 0.643 72 Figure 33. Matrixtexture for samples ofVB-02-03 upper diamicton 7A/10A ratios and the gamma ray log that was recorded at this core (Figure 36). This would suggest that potassium, which is the most important naturally occurring radioactive element in soils, would be associated with clays that produce a difilaction peak at the angle corresponding to 7A; these clays arekaolinite and chlorite. Separating the extensive upper diamicton unit from the diamicton at the bottom of the core are Units 2 through 5, consisting of lacustrine and outwash sediments· which together make up 3. 7 meters of the core. Unit 2 is a medium sand that fines downward into Unit 3, a laminated layer of clayey silt. Sediments abruptly mean-0.606 7 6+------'------, 5+------ �4+------ l 3 +------. 2 +------; 0 +-----r------.� 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.1 1.2 1.3 1.4 7/10 A peak-height ratio Figure 34. Histogram of 7All OA ratios for VB-02-03 upper diamicton --.J v,J 74 0.0 ------� -15.0 -20.0 · -25.0 -35.0 +------,------,------,------r------i 0 0.2 0.4 0.6 0.8 1.2 7/10ratio Figure 35. 7A/10A ratios with depth for VB-02-03 75 -15 -20 0 2 4 6 8 10 12 7/10 ratlo*10; CPS/100 :-Gamma ray log -7/10 ratio I Figure 36. 7All OA and gamma ray log with depth for VB-02-03 76 change to a dense, consolidated layer of laminated clayey silt. A very well sorted layer, the mean texture is 0.0% gravel, 0.3% sand, 59.4% silt, and 40.3% clay. The core ends in a lower gray diamicton unit that is very dense with abundant shale clasts. The mean matrix texture is 26.1 % sand, 65.0% silt, and 8.9% clay (Figure 37). The mean 7All OA peak-height ratio, as determined from 4 samples, is 0.643 (Figure 38). Figure 37. Matrix texture for samples ofVB-02-03lower diamicton mean-0.643 3 2 I 0 -+----,---.....,...---,-- 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.1 1.2 1.3 1.4 7/10 A peak-height ratio Figure 38. Histogram of 7AII0Aratios forVB-02-03 lower diamicton .....:i .....:i CHAPTER N DISCUSSION Correlation of the units described in this study was attempted with diamictons as well as with thick lacustrine sequences. Correlation of thinner units, or of units composed of fluvial deposits, was not attempted because of the small amount of data collected and the large area over which the cores were drilled. Considering the many differentdepositional environments that are present in a glacial setting, andthe rate of change in depositional processes, it is not expected that all units could be correlated. Lacustrine units, however, are likely to be preserved. Glacial diamictons, also, are likely to be more continuous in nature and are often highly resistant to erosion, making correlation between these types of deposits most likely to be successful. Glacial diamictons arealso important for correlation because they represent a glacial advance or retreat across the site. Correlations are based on stratigraphic, topographic, textural,and clay mineralogydata. CorrelationofDiamicton Units StratigraphicPosition Five cores, including VB-99-03, VB-01-09, VB-02-01, VB-02-02, and VB-02-03, contain two diamicton units, one of which occurs at the surface, and one 78 79 of which occurs at depth. In four of the cores, the upper diamicton ranges in thickness from 1.5 meters to 7 meters, and the lower diamicton ranges in thickness from 2.5 meters to 7 meters; however, in two cases drilling was stoppedin the lower diamicton, so this unit could have a greater thickness than what was reported. The upper diamicton in VB-02-03 is 26.2 meters in thickness, which is an order of magnitude thickerthan the other upperdiamicton units. Thiscore was collected from a borehole drilled on the Lake Border moraine. The unusual thickness could mean that this is actually more than one diamicton unit. This core will be described in more detail later in this chapter. The core VB-01-07 is the only core in which no diamicton unit is present. This core contains approximately 23 meters of lacustrine sediment below about 11 meters of fluvialsand and gravel. Two of the remaining cores, VB-01-09 and VB- 02-02, also contain a significant amount of lacustrine sediment that separates the upper and lower diamicton units. The thickness in VB-01-09, which is about 23 kilometers to the west ofVB-01-07, is approximately 27 meters. The thickness of the lacustrine deposits in VB-02-02, which is about 15 kilometers west of VB-01-09, is about 21 meters. There is only a small amount of lacustrine sediment in VB-02-03, amounting to a total thickness of less than I meter. Two cores that do not fit this pattern are VB-99-03 and VB-02-01. Although VB-99-03 doescontain some lacustrine sediment, the total thickness is less than 3 meters. Another difference between this core and the other cores is the depth 80 separating the two diamicton units, which, in four of the cores, is between 18 and 30 meters. The distance separating diamicton units in this core is only about 10 meters,most of which is very coarsein nature. The other core, VB-02-01, does not have any lacustrine sediment between diamicton units. The sediments separating diamictonunits in this core consist largely of medium to coarse sand and gravel. Although the sand unit below the lower diamictonfines downward, it is still coarseto medium sand with less than 1 % silt. TopographicConsiderations The topography in Van Buren County varies from around 180 meters above sea level in the westernpart of the county near Lake Michigan, to nearly 300 meters above sea level on the Kalamazoo moraine in the southeastern part of the county. The major uplands in the center of the county arethe Kendall �oraine, on which VB- 99-03 was drilled, and a drumlin on an upland originally mapped by Leverett and Taylor (1915) as the Valparaiso moraine, on which VB-01-09 was drilled. The surface elevation of these two locations is over 240 meters above sea level. Figure 39 is a topographic profile that shows the elevations of these two cores in the context of their surroundings. The cores VB-01-07, VB-02-02, and VB-02-03 were drilled at elevations of 204 meters above sea level (VB-02-02), 215 meters above sea level (VB-02-03), and 238 meters above sea level (VB-01-07) (Figure 40). Although the latter core is the 81 VB-01-09 VB-99-03 A' 252 � 1921 e 0 �.�7.4 14. 7 ¢d?½?F±f22.0 29.4 36.8 g44.0 km Figure 39. Topographic profile A-A' over a DEM basemap (USGS DEM) highest in elevation, it is also the farthest east, which is the direction of an overall increase in elevation. Thus, even though VB-01-07 is at a higher elevation than the two above-mentioned cores, it is located at a slightly lower elevation compared to its immediate surroundings. The sediments comprising the upper part of this core are coarse sands and gravel that were deposited in a high-energy environment. Water 82 VB-01-07 B VB-02-03 VB-02-02 � B' .½f:¥-1 ---� r::bi¼tgg_0 8.8 17.6 26.4 35.2 �44.0 �:=i-52.8 km Figure 40. Topographic profile B-B' over a DEM basemap (USGS DEM) that deposited these sediments may have had enough energy to erode an upper diamicton that may have been present at the surface in this location before the fluvial sediments were deposited. The core VB-02-03, at 215 meters above sea level, is located on the crest of a thin ridge mapped by Leverett and Taylor (1915) as the Lake Border moraine. This ridge rises slightly above the land in the immediate vicinity. 83 As is evident from the profiles and from the DEM, the elevation of VB-02-02 is similar to much of the area in the western part of the county. Topography plays an important role in the stratigraphy of VB-02-01. The elevation of this location is around 230 meters above sea level, which is nearly 30 meters higher than the land to the west, north, and northeast of this upland (Figures 41 and 42). The morphology and topography of this featuremight be related to the VB-02-01 C ------+- \ C' r:�0 = 3.8 --7.7;;_;¢L 1 ------+;ll.5r:±::115.3 19. I �-23.30 km Figure 41. Topographic profile C-C' over a DEM basemap (USGS DEM) 84 VB-02-01 ...., 747.------,------,---->kc=-----.------,------, -.. D' 6.7 10.0 13.3 16.6 km Figure 42. Topographic profile D-D' over a DEM basemap (USGS DEM) character of the sediments that comprise this core. As discussed earlier, this core contains two diamicton units separated largely by sand and gravel deposits. This differs from the general stratigraphic frameworkby not having lacustrine sediments between the diamicton units. The high elevation of this feature in relation to its 85 surroundings suggests an alternate correlation of the diamicton units. The lower diamicton in VB-02-01, which is nearly 20 meters lower than the surface of the core, lies approximately at the same elevation as much of the land surface to the west, north, and northeast. An alternateinterpretation would bethe correlationof thelower diamicton with the upper diamicton of VB-02-02, which is about 20 kilometers to the north, with both of these diamicton units being between 200 and 210 meters above sea level. Textural Comparisons Figure 43 shows a ternarydiagram in which the matrixgrain-size distributions of all of the diamicton samples are plotted. Samples from VB-02-03, from the Lake Border moraine, tend to have a greater percentage of silt and clay in the matrix. Based on the information presented to this point, there is no clear way to decipher whether the 26-meter thick diamicton unit in this core is a single unit or if it represents multiple tills. Hence, the data fromthat core will not be considered at this point. The remaining diamictons are divided between those that are interpreted as Saugatuck till and those that are interpreted as Ganges till. These are shown in Figures 44 and45. According to these results, these diamicton units cannot be clearly distinguished solely from their matrix compositions, although the Saugatuck till appears to have a greater amount of sand relative to silt, whereas the Ganges till appearsto have a greater amountof silt relative to sand. Monaghan et al. (1986) and Wong (2002) reportedmean matrix textures for 86 clay + VB-99-03 upper diamicton • VB-99-03 lower diamicton * VB-01-09 upper diamicton II VB-01-09 lower diamicton � VB-02-01 upper diamicton � VB-02-01 lower diamicton + VB-02-02 upper diamicton 6. VB-02-02 lower diamicton 0 VB-02-03 upper diamicton □ VB-02-03 lower diamicton Figure 43. Matrix textures fromall of the diamicton samples 87 clay Figure 44. Saugatuck till matrix textures the Saugatuck and Ganges tills but were not able to differentiate the tills based on matrix textures. Monaghan et al. (1986) reported a mean matrix texture of 36% sand, 42% silt, and 22% clay for the Saugatuck till, and 59% sand, 22% silt, and 19% clay for the Ganges till. Wong (2002) reported mean matrix texture values of 44% sand, 33% silt, and 29% clay for the Saugatuck till, and 41% sand, 36% silt, and 19% clay forthe Ganges till. Mean matrix texture values forthis study are 59% sand, 35% silt, and 6% clay for the Saugatuck till, and 39% sand, 53% silt, and 8% clay for the 88 clay Figure 45. Ganges till matrix textures Ganges till. Correlation by t-test was not attempted on the matrix textures since neither the range of values in the Saugatuck nor the Ganges till within this study are normally distributed, and since the matrix texture values reported by Monaghan et al. (1986), Wong (2002), and this study all differconsiderably. 89 Insightsfrom Clay Mineralogy The ratio of the 7A to the l0A peak on an X-ray diffractogram of the clay sized fraction has been used with success. to characterize and correlate glacial till units across regions to at least the county scale (e.g. Monaghan et al., 1986; Monaghanand Larson, 1986; Gardner, 1997; Flint, 1999; Wong, 2002). In particular, Monaghan et al. (1986) identified three till units in southwest Michigan by stratigraphic position as well as by differences in their mean 7.AllOA peak-height ratios. These tills were informallynamed, fromoldest to youngest, the Glenn Shores till, Gangestill, andSaugatuck till. Their mean7.All0A ratios, respectively, are1.22, 0.85, and0.58. Student t-tests were performed comparing mean 7All 0A ratios from diamicton units from this study. t-tests compare samples with normally distributed populations to determine whether or not the meansare significantly different. Table 9 shows the results of the t-test comparingthe mean7 All 0A ratio fromeach diamicton unit to each other diamicton unit in this study. Basedon these results, the following diamictons were interpretedto bethe Saugatuck till: VB-01-09 upper diamicton,VB- 99-03 lower diamicton, and VB-02-01 lower diamicton. By the same reasoning, the following diamictons were interpreted to be the Ganges till: VB-01-09 lower diamicton and VB-02-02 lower diamicton. No distinct 7All 0A ratios were obtained from the tills at the surface in VB-99-03, VB-02-01, and VB-02-02; these are interpreted as Saugatuck till based on stratigraphy. In two cases the comparison of diamictonunits failed the expected t-test results. This was the case in the comparison 90 Table 9 t-test results forthe comparison of diamicton units. UNITS Degrees of t(a/2,df) t calculated Same freedom populations? VB-01-09 upper till 13.41 2.15 4.17 NO VB-01-09 lower till VB-01-09 upper till 11.97 2.18 0.33 YES VB-99-03 lower till VB-01-09 upper till 13.05 2.16 1.74 YES VB-02-01 lower till VB-01-09 upper till 9.23 2.25 2.26 NO VB-02-02 lower till VB-01-09 lower till 5.58 2.40 6.50 NO VB-99-03 lower till VB-01-09 lower till 13.94 2.12 10.85 NO VB-02-01 lower till VB-01-09 lower till 3.36 3.00 1.92 YES VB-02-02 lower till VB-99-03 lower till 5.19 2.52 3.61 NO VB-02-01 lower till VB-99-03 lower till 3.34 2.95 2.76 YES VB-02-02 lower till VB-02-01 lower till 3.20 3.10 5.46 NO VB-02-02 lower till 91 of VB-99-03 lower till with VB-02-01 lower till, and the comparison of VB-99-03 lower till with VB-02-02 lower till. Ratios from VB-02-0 I lower till are lower than any other till unit, ranging from0.328 to 0.611 with a mean value of 0.397. Although this mean is much lower than the mean ratio of VB-99-03 lower till (0.618), it is much more likely to be correlated to the Saugatuck till than it is to theGanges till. It is not clear why the t-test shows VB-99-03 lower till and VB-02-02 lower till as being the same population. The means for these two units are 0.618 and 0.812, respectively, which would appear to be significantlydifferent. The fact that the t-test indicates that these two means are statistically similar could be the result of limited degrees of freedom in the comparison, since the means from each population were determined fromonly 3 samples. Although several researchers ( e.g. Monaghan et al., 1986; Monaghan and Larson, 1986; Gardner, 1997; Dodson, 1985; Flint, 1999; Wong, 2002) have successfully correlated diamicton units across large geographic areas based partially on 7All oA ratios, correlation based entirelyon 7All 0A ratios canbe problematic. Of particular concern are the minerals or suites of minerals that comprise the 7A and the lOA peak. Flint (1999) demonstrated that similar 7A/10Aratios could be the result of differentsuites of minerals. For example, a diffraction peak at 7A could be produced by the 002 plane of chlorite, the 001 plane of kaolinite, or the 002 plane of vermiculite. Thus there is a possibility that tills with similar 7All 0A ratios yet with differentsuites of minerals could be correlated. 92 Both Flint (1999) and Wong (2002) analyzed clay mineralogy samples that ° were air-dried, ethylene glycol solvated, and heated to 315 C. In addition to air-dried samples, the heating procedure proved to be most useful for correlating and differentiating diamicton units. Thus, in addition to running air-dried samples forX ° ray diffraction analysis, samples were also heated to 315 C. This provided a means by which to differentiate chlorite from vermiculite. Chlorite and vermiculite are the dominating minerals that produce a 14A peak (Rieck, 1976; Flint, 1999). When ° heated to 315 C for one hour, however, the structure of vermiculite will collapse from a d-spacing of 14A to 1 0A, whereas chlorite will remain unaffected. Results from ° heating samples to 315 C are displayed in a plot of14A/10A as a functionof7Al10A peak-height ratios (Figure 46). A large percentage of Saugatuck till samples plot near the x-axis. These samples either have no 14A peak or a very small 14A peak after heating. The absence of a 14A peak suggests that these samples contain vermiculite and little to no chlorite, since chlorite would be unaffected by heating and would retain its 14A d-spacing. Samples containing a greateramount of chlorite have higher 14A/10A ratios and thus plot higher on the vertical axis. Most of the Ganges till samples, as well as some Saugatuck till samples, contain chlorite. There are, however, no clear patterns that could distinguish the Saugatuck from the Ganges till based on these results. Very little qualitative clay mineralogy research has been done on Lake Michigan lobe diamictons. Wong (2002) reported that most samples of Saugatuck till and Ganges till contained chlorite, whereas only 2 of her 34 samples contained 93 vermiculite. Wong considered the vermiculite to be a possible weathering product of chlorite. Monaghan et al. (1986) performed qualitative clay mineralogy analyses on a portion of their samples and concluded that chlorite, illite, kaolinite, and minor amounts of vermiculite were present in the samples, whereas smectite was generally absent. They also concluded that the 1 0A peak is largely composed of illite, and the 7 A peak is largely composed of kaolinite and/or iron-rich chlorite (Monaghan et al., 1986). VB-02-03 The core drilled on the crest of the Lake Border moraine is similar to several other cores by having two diamicton units separated by fluvial and lacustrine sediments. It differs from other cores by the great thickness of the upper diamicton and the small thickness of sediments separating the two diamicton units. The mean 7Alt oA ratio for the upper 26.2 meters of diamicton is 0.606, and the mean for the lower diamicton unit is 0.643. Figure 35 is a graph of 7A/10A ratios with depth in this core, including ratios from the upper diamicton, the lower diamicton, as well as ratios from fluvial and lacustrine sediments between the two diamictons. There is considerable variation in mean 7 All 0A ratios within the upper diamicton unit, and there is no obvious trend of ratios with depth. t-tests comparing the mean 7 AllOA ratios of the two diamicton units with each other and with the upper and lower diamictons in VB-01-09 indicate that both diamicton units in VB-02-03 have similar mean ratios to the upper diamicton in VB-01-09 and indicate that theyare similar to 0.2 • 0.18 • 0.16 & & I 0.14 • & • 0.12 a Saugatuck till 0.1 • • ■Ganges till 0.08 . • & 0.06 • 0.04 & & 0.02 • 0 I - - -.;. - � 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 7/10 ratio Figure 46. 7AIIOAvs. 14AIIOA ratios fordiamicton samples heated to 315 °C \I:)� 95 each other (Table 10). Based on the results from clay mineralogy, these two diamicton units would correlate to the Saugatuck till. Stratigraphic relationships, however, would suggest the upper diamicton is the Saugatuck till and the lower diamicton is the Ganges till. As previously stated, the matrix compositions of both diamicton units in VB-02-03 differ significantly from other diamicton units in that they have a much greater percentage of clay. Table 10 t-test resultscomparing diamicton units fromVB-02-03 to VB-01-09 Unit Degrees of t(a/2,df) t calculated Same populations? freedom VB-02-03 upper till 13.84 2.14 0.19 YES VB-01-09 upper till VB-02-03 lower till 6.42 2.40 0.41 YES VB-01-09 upper till VB-02-03 upper till 21.40 2.08 7.11 NO VB-01-09 lower till VB-02-03 lower till 3.60 2.95 2.65 YES VB-01-09 lower till VB-02-03 upper till 3.60 2.85 0.33 YES VB-02-03 lower till 96 The exceedingly large thickness of upper diamicton is only part of the problem with core VB-02-03. The location at which the core was drilled, the crest of the Lake Border moraine, is approximately 3 km due west of the location of VB-02-02. There is an increase of only approximately 11 meters in elevation from VB-02-02 to the Lake Border moraine. A reasonable expectation might be a close correlation between units in these two cores. However, whereas the upper diamicton in VB-02-03 is 26.2 meters in thickness, the upper diamicton in VB-02-02, just 3 km to the east, is only 3.0 meters in thickness. Although data collected for this study do not yield a clear explanation for the thickness of the upper diamicton unit in VB-02-03, two hypotheses will be proffered. The upper diamicton could be composed of several thrusted and stacked units of the same basal till unit. Both the gamma ray log and the percentage of clay (Figure 32) show a cyclic pattern of alternating clay-rich and clay-poor layers. Each of these layers, approximately 3 meters in thickness, could be one sequence of the original basal till. Thrusting by the glacier in this location could be explained by sudden changes in basal hydraulic conditions; for example, the wet-based lobe could have become frozen to its bed at a point near the Lake Border moraine, which could have caused the ice and basal sediment upgradient to be thrusted above the ice that is frozen to its bed. The bedrock topography might influence the diamicton thickness in this location (Figure 5). Bird (in preparation) produced a bedrock topography map of Van Buren County that suggests the Lake Border moraine coincides with a bedrock valley. 97 The elevation of this valley is as low as 50 meters above sea level. This is approximately 100 meters lower than the surrounding bedrock elevation and 150 meters below the surface of the Lake Border moraine. Leverett and Taylor (1915) also reported bedrock elevations on the Lake Border morainic system in northern Michigan that were near sea level. Such a deep valley .could offer protection from erosion for preexisting sediments. Thus, the sediments in this location, including the sediments in VB-02-03, could be sediments from much earlier glacial advances that were preserved. However, recent drilling in Allegan County, directly north of Van Buren County, revealed bedrock at a depth of approximately 50 meters, which woqld suggest that the thick accumulation of sediments is a local phenomenon, and that the interpreted bedrock valley did not play a role in the genesis and overall character of the Lake Border moraine. Correlation of LacustrineUnits The cores in this study reveal thick lacustrine sediments occupying a stratigraphic position between the Ganges and the Saugatuck tills. The primary methodology for the correlation of lacustrine units is based on stratigraphy. Textural characteristicswill also be considered, as will clay mineralogy on a limited number of samples. 98 StratigraphicPosition Thick lacustrine sediments ranging from20 to 30 meters occur in three of the cores, including VB-01-07, VB-01-09, and VB-02-02. In the latter two cores, the lacustrine sediments are present stratigraphically between the Ganges and Saugatuck tills. There areno till units in VB-01-07. In this corethe lacustrinesediments occupy a position between two thick, coarseoutwash deposits. One of the cores, VB-99-03, contains a smaller thickness of lacustrinesediments. These sediments, approximately 6.1 meters in thickness, occupy the bottom of the core and are immediately below coarse gravel. The sediment in VB-02-01 that separates the two till units is interpretedto be fluvial rather thanlacustrine, as the sediment in this core is coarser thansediment in other cores. The sediments in this core contain only a small fraction of very fine sand, silt, and clay. There is a small amount {~3 meters) of lacustrine sediment in VB-02-03 that separates two till units. This lacustrine sediment could possibly correlate with lacustrine sediments in the other cores, but it is not clear if these two till units in VB-02-03 arethe Ganges and Saugatuck tills. TopographicConsiderations Elevations forthe lacustrine sediment range from a low of approximately 182 meters abovesea level to approximately 243 meters abovesea level (Figure 47). The thickest lacustrine sediment occurs in VB-01-07, VB-01-09, andVB-02-02. Highest elevations oflacustrinesediment occur in VB-01-09, between 211.6 and242.4 meters above sea level. To the east, the lacustrine deposits in VB-01-07 lie between 205.4 250 240 ::::- 230 QI> .! l'G 3l 220 QI> .8 l'G I I!! 210 QI � .§. § 200 ; :IV w 100 I -+- • I 1soL 170 VB-99-03 VB-02-03 VB-02-02 VB-02-01 VB-01-09 VB-01-07 Core Figure 4 7. Lacustrine elevations and thicknesses \0 \0 100 and 227.3 meters above sea level (Figure 47). In the westernpart of the county, the lacustrine deposits in VB-02-02 are at elevations between 201.0 and 177.5 meters above sea level. Located to the north of VB-01-07, VB-99-03 contains 6.1 meters of lacustrine deposits located at elevations between 212.8 and 218.9 meters above sea level. It is quite probable that these deposits exteQd to·a depth beyond the depth of penetration of this core; this would result in a greater thickness of lacustrinedeposits .,at this location. It is not clear if the 3 meters of lacustrine sediments in VB-02-03 are correlatable to the other lacustrine units in Van Buren County. Although there is a: question regarding the correlation of the diamicton units in VB-02-03, andalthough the thickness of lacustrine deposits in VB-02-03 is significantly less than VB-02-02, which is only 3 km to the east, the elevation of the lacustrine sediments could correlate to the elevation of lacustrine sediments in VB-02-02. Since these cores are geographically very close to each other, a significantdifference in elevation would be evidence against correlation of the lacustrine unit. However, the elevation of the lacustrinesediments in VB-02-03 ranges from185.1 to 188.5 meters abovesea level. Although this is a significantly thinner sequence of lacustrine sediments, the elevations arewithin the range of lacustrine sediments in VB-02-02, between 177 .5 to 201.0 meters above sea level (Figure 47). Textural Comparisons The sequence of lacustrine sediments in the three cores that have the thickest lacustrine units, VB-01-07, VB-01-09, and VB-02-02, do not have similar textural 101 characteristics. The lacustrine sequence in VB-01-07 consists of approximately 5 meters of very fine sand and silt at the base, overlain by 2.8 meters of clayey silt. This sequence is repeated and capped with a thin ( ~1.5 meter) layer of gravel. Above the gravel layer is an additional 7.3 meters of silty sand. The lacustrine sediments in VB-01-09 are largely silty sand and sandy silt. Directly above the Ganges till is approximately 2 meters of very fine sand, which is overlain by 3.4 meters of sandy silt. The sandy silt grades upward into 12.8 meters of silty sand, above which is 10.0 meters of sandy silt. The majority of the lacustrine sediment in this core, thus, is in the very fine sand to silt range, with very little clay present and no clayey units present, whereas VB-01-07 contains two clayey units. Approximately 23 meters of lacustrine sediments separate the Ganges and the Saugatuck tills in VB-02-02. Directly above the Ganges till is 1.5 meters of clay and silt. Above the clay and silt is 7.6 meters of fine sand and silt, which is capped with a thin (~1 meter) layer of sand and gravel. More than 9 meters of fineto very finesand lie above the gravel layer. Above this layer is approximately 2 meters of laminated silt with dropstones. These were the only dropstones identifiedin any of the cores. The lacustrine sediments near the bottom ofVB-99-03 are similar to the upper section of the lacustrine sequence in VB-01-07, which is in close proximity to this core. These sediments are approximately 6 meters in thickness and are comprised of fine sand to silt. There is only a thin (~3 meters) lacustrine unit in VB-02-03. Approximately 0.5 meters of clayey silt lie directly above the lower diamicton. Above this layer is 102 less than one meter of medium to fine sand, above which is another clayey silt layer (~2 meters). Insightsfrom Clay Mineralogy Samples from VB-01-07, VB-01-09, and VB-02-03 were analyzed for clay mineralogy (Tables 4, 5, and 8). Of particularinterest are the results fromVB-01-07. From each of the two clayey silt units 3 slides were prepared for XRD. The lower clayey silt unit yields a mean 7 All 0A ratio of 0. 752 (n=3), whereas the upper clayey silt unit yields a mean 7All 0A ratio of 1.357 (n=3). It would be reasonable to assume that 7All 0A ratios for lacustrine sediments would be similarto ratios for diamictons. This assumes that the clays present in the diamicton units and in the lacustrine units are derived from a similar source, or that the clays in the lacustrine unit are derived froman underlying diamicton unit. 7All 0A ratios forthe Ganges and Saugatuck tills as reported in this study as well as in Monaghan et al. (1986) are 0.9 and 0.6, respectively. A low 7A/10A ratio would be the result of clay that is illite-rich, since illite is the dominant clay mineral with a 1 0A diffraction peak. This can be expected from the erosion of shale. A high 7All 0A ratio would imply that the clay has an illite-poorsource. One possible, although highly speculative, explanationfor the high 7All 0A ratio in the upper clayey silt unit is that the clay was derived from Saginaw lobe deposits. The Saginaw lobe advanced over limestone and sandstone, as well as existing glacial sediments. Monaghan and Larson (1986) report mean 7AllOA ratios for Saginaw lobe tills that are significantly higher than Michigan lobe tills. The 103 Fulton till, which is the diamicton at the surface of the Tekonsha moraine and the Leonidas Drumlin Field, has a mean 7AII0A ratio of 1.13. Thus, a possible explanation for the differencebetween the two mean 7All 0A ratios of the clayey silt units is that the lower unit contains clay derived from Michigan lobe meltwater and sediment, whereas the upper unit contains clay derived from Saginaw lobe meltwater and sediment. This could support Kozlowski's hypothesis (in preparation) of a Saginaw lobe catastrophic outburst forthe formation of the Kalamazoo River Valley. Correlation with Other Data A rotasonic core drilled in 1999 near Otsego, Michigan, located directly north of the locationof core VB-99-03, is composed of approximately 8 meters of medium sand, underlain by approximately 9 meters of lacustrine clay, below which is 7 to 8 meters of diamicton. The sediments below the diamicton are coarse sand andgravel that fine downward. The lacustrine sequence above the diamicton could possibly correlate with the lacustrine sequence above the Ganges till in Van Buren County. Wong (2002) analyzed clay mineralpgy from two samples from the diamicton in this core. 7AII0A ratios from these results are1.091 and 0.688, which are interpreted as the Ganges till. This core, thus, supports the generalized stratigraphyfrom this study based on evidence from stratigraphic as well as from clay mineralogy. Additional clay mineralogy work by Wong (2002) indicates the Ganges till exists at depth at several locations throughout Van Buren andAllegan Counties. 104 Other rotasonic cores analyzed by Bird (in preparation) reveal a similar sequence of thick lacustrinesediments overlying a diamicton at depth. Results of X ray diffraction from diamicton units at depth in two cores yield a meanvalue of 0.65 (n=3). Additional XRD data from these diamicton units would be helpful, since this value lies between values of the Saugatuck and Ganges till and since this mean is derived from a small population (n=3). The stratigraphy of the cores, however, indicates that the diamicton at depth correlates with the Ganges till. In addition to rotasonic cores, Bird (in preparation) also examined water well records in south central Van Buren County, from which he interprets a stratigraphy of a lower diamicton overlain by a significant thickness of lacustrine deposits, capped by a discontinuous diamictonat the surface. GrainSize Statistical Parameters Grain-size statistical parameters, including mean, sorting, skewness, and kurtosis, were calculated foreach sample andare displayed in Chapter III ascurves in the composite log figures for each core. To determine the range of statistical values produced by fluvial,lacustrine, and by glacialdeposition, statistical values were taken from316 samples whose environments of deposition have beenwell established. The most useful of these results areplots of mean grainsize versus sorting(Figure 48) and mean grain size versus skewness (Figure 49). Lacustrine sediments are characterizedby a high mean phi size (small mean diameter) and by a small rangeof low sorting values (well sorted), ranging from 0.5 - 1.5. Diamictons are also 4.00 1 • • 00 • I •• • 3.00 ciaTicton i 2f,() ·;; • ciaricton .& • S: 200 ■flLNial .& lacustrine f,() 0 1. • rl' 1.00 0 fiO I fll.Nial O. .& lacustrine 0.00 -4.00 -200 0.00 200 4.00 6.00 8.00 mea,(phi size) Figure 48. Mean grain size versus sorting from 316 samples 7.00 6.00 5.00 4.00 ,- .§ 3.00 • ♦ diarricton S: 2.00 • ■ fluvial GIi GI I • lacustrine 1.00 • A iGIi A 0.00 -1.00 -2.00 -3.00 -4.00 -2.00 0.00 2.00 4.00 6.00 8.00 mean (phi size) Figure 49. Mean grain size versus skewness for316 samples 0 0\ 107 characterized by a high mean phi size but are poorly sorted. The range of sorting in diamicton samples is large than the range of sorting in lacustrine samples, ranging from 1.5 - 3.5. Fluvial samples have a lower mean phi size than lacustrine and diamicton samples. The range of sorting values in fluvial samples is very large, ranging from well-sorted samples with sorting values of approximately 0.5, to poorly sorted samples, with sorting values of approximately 3.5. Skewness values for most lacustrine sediments range from phi values of 0 - 2.0. This indicates that lacustrine sediments range from a unifonn distribution around the mean to having a larger amount of sediment on the fine side of the mean. Skewness values for diamicton samples range from -2 - 0, indicating that samples from diamictons have a larger amount of sediment that is coarser than the mean. Fluvial samples have the greatest range of skewness values, with most of the values between -1.0 and 2.0. CHAPTERV CONCLUSIONS Analysis of six cores drilled throughout Van Buren County indicates a general stratigraphic framework of a lower diamicton, a significant thickness of lacustrine sediments, and a diamicton at the surface (Figure 50). Mean 7AIIOA ratios of the two diamictons are 0.540 for the upper diamicton and 0.908 forthe lower diamicton. These stratigraphic and clay mineralogy results correlate with the informally named Saugatuck and Ganges tills of Monaghan et al. (1986). These results also agree with work done by Wong (2002) and Bird (in preparation). Textural comparisons of diamictons as well as lacustrine units, both between units in this study as well as between units of this study and units of other workers, were not as useful as stratigraphicand clay mineralogy data forcorrelation and fordifferentiating units. It is necessary, however, to consider the elevation and topography of the boring location when comparing to other borings, as this can yield insights that can aid in the interpretation and correlation of the stratigraphic units. Five of the cores in this study, for example, were drilled on uplands, whereas one core was drilled on a lowland. The core drilled on the lowland, VB-01-07, is the only core that did not have a diamicton at the surface. An episode of fluvial erosion may have erased the record of a diamicton that may have existed at th� surface at this location. A core 108 West VB-99-03 East 2-'0 230 22 0 V iJ-'-'.M-'LJ'., \:,,,,1,1:· 1'"':1-....:� - - - - .._,,s . - .... 210 al 200 190 LEGEND 4 S a• rat u < k ti 11 VB-02-02 f:�jb>l w�;)�;;;.�:'''.I flu vi al • :a. n d r;::a.nr•• till ��!l·�����:� f l u v i ::a.1 rr ::a.vel j:_ - -] l::a.,utirint Figure 50. Generalized cross section of Van Buren County, Michigan (not to scale). Core locations are shown in Figure 2. 0 l,O 110 analyzed by Bird (in preparation), VB-99-01, was also drilled on the same lowland feature as VB-01-07. This core also lacks a surface diamicton. A core drilled on an upland, VB-02-01, contains both an upper and lower diamicton, as do most of the other cores, but a close examination of the topography of this boring location reveals that the lower diamicton lies at the same elevation as the_ upper diamicton in the core VB-02-02, which is to the north of the former core. This diamicton at depth is interpreted to be the Saugatuck till based on its topographic position as well as clay mineralogy. The core drilled on the crest of the Lake Border moraine, VB-02-03, contains an anomalously thick sequence of surface diamicton. Although the stratigraphy of this core correlates with the general stratigraphy of the county, the unusual thickness of the surface diamicton in this core demands an explanation. It is not clear if this diamicton is actually severalthrusted and stacked layers of one basal till unit, if this is actually the Saugatuck and Ganges till in contact with each other, or if some other glacial process is responsible forthis thick unit. The stratigraphy of Van Buren County suggests an advance of the Lake Michigan lobe, as recorded by the Ganges till, to the Tekonsha moraine (Monaghan et al., 1986). Following this advance, the ice retreated out of the area and a significant period of lacustrine deposition occurred. This lacustrine deposition is recorded in the thick sequence of fine sediments above the Ganges till. A final advance of the Lake Michigan lobe to the Kalamazoo moraine position occurred. This advance deposited the Saugatuck till at the surface in Van Buren County (Monaghan et al., 1986). The 111 flowdirection forthis advance was from the northwest to the southeast. Evidence for this is the orientation of the Kalamazoo moraine perpendicular to the flow direction. Drumlins trending east-southeast on the Valparaiso upland were formed subglacially during this advance (Kehew et al., 2001 ). Appendix A Textural Analysis Results 112 sample depth (m) unit sieve 10 sieve 18 sieve 36 sieve 60 sieve 120 sieve 230 silt clay total wt VB-99-03A 1.2 1 144.97 7.45 10.74 58.89 139.57 49.46 62.27 19.85 493.2 VB-99-038 2.1 2 0 0.03 0.15 39.88 210:37 62.32 4.67 0.77 318.19 VB-99-03C 3.1 2 169.57 29.99 40.02 42.47 130.47 50.02 10.37 1.42 474.33 VB-99-03D 3.7 2 2.94 1.42 8.08 49.69 187.83 41.31 39.76 5.41 336.44 VB-99-03E 4.6 2 0.07 0.04 1.93 72.45 221.08 58.75 5.46 2.37 362.15 VB-99-03F 5.2 3 129.92 35.13 55.27 81.08 78.33 13.5 31.4 4.05 428.68 VB-99-03G 5.8 3 163.83 11.28 48.21 177.84 35.77 5.2 5.61 1.68 449.42 VB-99-03H 6.4 3 138.05 24.02 47.76 103.01 81.35 8.81 22.16 3.07 428.23 VB-99-031 7.0 3 66.24 25.51 73.88 172.53 88.91 16.36 70.2 9.9 523.53 VB-99-03J 7.6 3 19.01 8.22 20.76 126.22 182.29 51.58 43.07 6.01 457.16 VB-99-03K 8.2 4 0.15 0.71 25.62 175.87 134.29 11.4 28.01 1.26 377.31 VB-99-03L 8.8 4 0.63 1.22 8.3 82.11 171.49 13.28 39.94 7.79 324.76 VB-99-03M 9.5 4 0.4 0.65 2.37 8.44 6.09 11.25 379.2 41.55 449.95 VB-99-03N 10.1 4 0.12 0.24 0.76 30.2 141.98 60.84 249.37 16.98 500.49 VB-99-03O 10.7 5 4.55 4.11 13.13 60 87.67 66.3 340.98 46.56 623.3 VB-99-03P 11.6 5 43.95 7.19 13.52 82.08 134.38 92.22 253.45 49.07 675.86 VB-99-03O 12.2 5 20.31 4.88 9.88 49.6 108.99 88.7 235.47 41.33 559.16 VB-99-03R 13.1 6 16.13 2.8 18.19 104.5 165.91 44.77 95.73 3.68 451.71 VB-99-03S 13.7 6 99.7 13.69 35.48 161.26 80.7 20.75 35.31 4.85 451.74 VB-99-03T 17.4 6 87.69 25.38 46 63.4 98 26.94 95.73 6.32 449.46 VB-99-03U 18.0 6 58.32 20.14 52.38 152.65 124.66 38.02 18.28 1.66 466.11 VB-99-03V 18.6 6 40.91 15.18 34.18 116.71 151.65 23.02 42.07 2.89 426.61 VB-99-03W 19.2 6 21.91 7.95 34.77 233.17 119.93 13.66 3.82 0.76 435.97 VB-99-03Y 20.1 6 6.83 14.89 40.88 69.72 108.06 31.67 79.92 2.92 354.89 VB-99-032 20.7 6 463.18 14.09 26.37 70.9 74.15 34.4 13.48 1.35 697.92 VB-99-03AA 21.4 6 20.17 138.96 159.02 83.85 32.96 4.67 4.85 1.12 445.6 VB-99-03AB 22.0 6 49.97 104.17 202.4 37.09 6.73 0.26 3.59 1.13 405.34 VB-99-03AC 22.6 6 47.38 55.64 123.34 167.6 19.32 0.89 2.43 0.82 417.42 VB-99-03AD 23.2 6 19.79 30.25 113.68 217.82 26.9 0.1 3.12 0.7 412.36 VB-99-03AE 24.1 6 32.03 15.98 104.75 220.68 23.38 2.29 1.55 0.77 401.43 VB-99-03AF 25.0 6 33.65 11.6 102.1 213.86 32.78 0.04 4.69 0.92 399.64 VB-99-03AG 25.9 6 27.55 10.22 95.88 252.38 26.37 4.25 7.22 1.01 424.88 VB-99-03AH 26.8 6 318.17 44.14 109.51 75.67 13.66 0.05 5.01 0.84 567.05 VB-99-03AI 27.8 6 393.89 49.03 38.25 39.02 17.38 4.46 5.25 1 548.28 VB-99-03AJ 28.7 6 379.21 44.03 35.92 59.14 66.93 0.36 16.52 1.1 603.21 - w- sample depth (ml unit sieve 10 sieve 18 sieve 35 sieve 60 sieve 120 sieve 230 silt clay total wt VB-99-03AK 29.3 6 73.44 30.17 96.23 128.8 64.51 11.28 6.7 1.19 412.32 VB-99-03AL 29.9 6 158.46 18.04 85.95 61.54 48.1 1.39 127.82 1.28 502.58 VB-99-03AM 30.5 6 27.09 3.23 16.92 18.84 99.2 1.11 293.86 1.85 462.1 VB-99-03AN 31.1 7 0.02 0.05 0.14 7.39 127.51 189.39 49.97 1.34 375.81 VB-99-03AO 31.7 7 0.07 0.11 0.16 18.59 163.62 1.26 182.3 1.3 367.41 VB-99-03AP 32.3 7 0 0.07 0.07 3.91 162.85 200.08 50.87 1.52 419.37 VB-99-03AQ 33.2 7 0.04 0.04 0.06 10.63 183.26 117.19 89.87 1.25 402.34 VB-99-03AR 33.9 7 0.03 0.01 0.08 20.45 174.1 126.18 30.94 0.99 352.78 VB-99-03AS 34.5 7 0.03 0.07 0.13 17.78 189.34 74.22 177.59 1.82 460.98 VB-99-03AT 35.1 7 0.05 0.07 0.3 14.94 254.09 176.37 31.05 1.25 478.12 VB-99-03AU 36.3 7 0.25 0.53 1.88 22.3 260.6 95.81 100.24 1.35 482.96 VB-99-03AV 37.2 7 0.28 0.68 1.2 31.86 157.85 157.48 61.58 2.66 413.59 VB-99-03AW 37.8 8 35.65 18.01 39.37 146.34 139.13 2.39 52.85 3 436.74 - sample depth (m) unit sieve 10 sieve 18 sieve 35 sieve 60 sieve 120 sieve 230 silt clay total wt vb-01-07A 0.915 1 150.89 48.46 57.99 84.42 24.76 4.82 11.23 1.24 383.81 vb-01-07B 1.83 1 28.2 18.38 48.21 140.6 77.39 43.71 21.71 3.28 381.48 vb-01-07C 2.44 1 66.71 19.46 36.64 147.4 58.05 10.35 17.84 2.34 358.79 vb-01-07D 3.355 1 152.8 100.83 64.12 60.33 15.8 10.21 20.33 1.83 426.25 vb-01-07E 4.27 1 191.88 75.62 102.26 53.25 11.29 4.02 7.88 1.21 447.41 VB-01-07F 5.185 1 174.88 79.88 76.51 75.53 20.04 14.82 20.12 2.1 463.88 VB-01-07G 6.1 1 138.19 101.49 98.73 55.44 9.19 5.54 11.46 1.85 421.89 VB-01-07H 7.015 1 103.73 82.41 105.59 80.62 60.86 7.9 8.91 1.12 451.14 VB-01-07i 7.93 1 132.29 96.08 99.08 66.37 13.67 8.56 12.74 1.85 430.64 vb-01-07i 8.845 1 163.16 74.12 82.16 55.17 13.84 6.18 12.36 1.55 408.54 vb-01-07k 9.455 1 96.88 74.71 87.52 89.47 44.15 15.88 19.63 2.11 430.35 vb-01-07L 10.065 1 96.89 37.29 62.9 110.7 99.7 12.82 13.43 2.12 435.85 vb-01-07m 10.675 1 0.24 5.73 35.21 119.49 171.88 33.7 33.47 4.91 404.63 vb-01-07n 10.98 2 134.77 72.13 88.78 60.33 21.9 10.73 17.85 3.45 409.94 vb-01-070 11.59 2 71.96 47.3 69.73 90.94 77.71 33 64.24 8.56 463.44 vb-01-07p 12.2 2 79.12 58.89 54.52 56.77 33 38.77 95.53 9.85 426.45 vb-01-07q 12.81 2 0 0.03 0.07 0.54 23.98 209.42 94.55 6.95 335.54 vb-01-07r 13.42 2 0.04 0.1 0.6 0.84 12.25 191.04 92.86 5 302.73 vb-01-07s 14.335 2 0.59 0.24 0.33 0.93 7.24 176.88 104.89 3.92 295.02 vb-01-07t 14.945 2 0 0 0.11 0.11 22.26 207.65 92.49 4.2 326.82 vb-01-07u 15.555 2 0 0.06 0.41 2.07 ·18.54 165.09 112.63 8.56 307.36 vb-01-07v 16.165 2 0 0.01 0.02 0.01 6.8 184.47 98.92 2.04 292.27 vb-01-07w 16.47 2 0 0.04 0.03 0.05 9.6 194.77 112.39 2.05 318.93 vb-01-07x 17.385 2 0 0.04 0.12 0.69 16.53 236.63 95.24 3.8 353.05 vb-01-07y 17.995 2 1.02 0.38 1.07 1.59 19.22 234.91 116.57 1.92 376.68 vb-01-072 18.91 3 60.79 40.8 123.69 155.33 7.89 3.87 7.92 1.32 401.61 vb-01-07aa 19.52 4 0 0.05 0.22 1.53 3.2 3.35 295.51 61.24 365.1 vb-01-07ab 20.435 4 0 0.01 0.01 0.04 0.67 5.31 282.13 26.47 314.64 vb-01-07ac 21.35 4 0 0.01 0.04 1.21 32.58 32.85 273.45 16.32 356.46 vb-01-07ad 22.265 5 0 0.03 0.15 0.59 49.42 248.4 47.57 1.28 347.44 vb-01-07ae 22.875 5 0 0.05 0.28 2.96 85.47 192.98 93.27 4.72 379.73 vb-01-07af 23.79 5 0 0.06 0.06 0.48 72.57 257.95 53.75 0.85 385.72 vb-01-07ag 24.705 5 0 0 0.05 0.4 23.51 250.4 66.37 1.07 341.8 vb-01-07ah 25.62 6 0 0.01 0.01 0.02 0.41 4.01 310.81 37.98 353.25 vb-01-07ai 26.23 6 0 0 0.03 0.06 2.77 17 382.38 30.43 432.67 ...... V, sample depth (m) unit sieve 10 sieve 18 sieve 36 sieve 60 sieve 120 sieve 230 slit clay total wt vb-01-07aj 26.84 6 0.04 0.07 0.06 1.7 24.47 52.49 273.73 28.6 381.16 vb-01-07ak 27.45 7 0 0.01 0.08 7.66 168.95 164.99 26.07 1.73 369.49 vb-01-07al 28.06 7 0 0.05 0.12 10.47 126.5 167.98 62.77 5.16 373.05 vb-01-07am 28.67 7 0 0.02 0.15 3.87 96.32 208.78 22.38 0.99 332.51 vb-01-07an 29.28 7 62.57 26.29 60.46 52.09 101.45 126.57 48.39 3.02 480.84 vb-01-07ao 29.89 7 3.06 0.27 0.52 1.1 87.28 248.33 69.71 3.64 413.91 vb-01-07ap 30.5 7 0.04 0.21 0.53 2.69 21.94 288.24 118.91 6.99 439.55 vb-01-07ao 31.11 7 0 0.09 0.85 2.37 3.21 259.66 211.04 10.07 487.29 vb-01-07ar 31.72 7 199.66 84.88 113.29 47.34 22.85 21.18 30.76 4.22 524.18 vb-01-07as 32.635 8 243.12 62.46 122.52 68.78 18.98 4.38 6.85 1.12 528.21 vb-01-07at 33.55 8 290.44 69.41 79.09 45.82 16.73 10.19 17.86 2.48 532.02 vb-01-07au 34.16 8 257.05 64.01 73.46 36.05 21.03 12.3 16.84 1.95 482.69 vb-01-07av 34.77 8 168.89 155.78 133.06 49.68 13.39 7.2 9.03 1.29 538.32 vb-01-07aw 35.685 8 340.92 63.04 77.67 37.87 9.42 5.92 10.64 1.81 547.29 vb-01-07ax 36.6 8 358.26 88.87 77.87 33.12 9.52 4.75 12.99 2.27 587.65 vb-01-07ay 37.21 8 410.75 48.07 29.58 20.29 8.75 9.38 16.29 2.46 545.57 vb-01-07az 38.125 8 295.98 38.46 51.05 80.48 54.22 25.92 49.43 6.57 602.11 vb-01-07ba 38.735 8 258.99 25.63 39.09 103.62 90.38 35.29 37.49 3.39 593.88 vb-01-07bb 39.65 8 278.48 36.3 29.18 80.73 70.55 55.68 28.07 2.53 581.52 vb-01-07bc 40.26 8 148.11 17.01 33.93 99.51 129.76 46.53 24.04 3.05 501.94 vb-01-07bd 40.87 8 144.99 72.3 69.34 104.49 56.89 30.34 50.24 4.99 533.58 - sample depth (m1 unit sieve 5 sieve 10 sieve 20 sieve 40 sieve 80 sieve 100 sieve 230 slit clay total wt vb-01-09f 0.6 1 16.91 9.68 16.13 38.38 154.97 20.77 40.89 26.87 5.89 330.49 vb-01-09a 1.2 1 21.46 1.02 2.06 5.53 58.83 17.97 67.87 122.25 14.39 311.38 vb-01-09h 1.8 1 18.47 2.39 2.63 7.69 30.58 11.84 72.88 160.8 18.23 325.51 vb-01-09i 2.1 1 10.07 0.74 1.04 1.55 15.82 27.5 230 71.24 12.84 370.8 vb-01-09j 2.4 1 55.14 10.76 11.69 20.87 89.88 17.92 54.1 140.03 28.03 428.42 vb-01-09k 3.4 1 48.42 5.82 7.17 13.45 52.05 9.95 25.52 161.8 25.61 349.79 vb-01-091 4.3 1 29.78 6.87 9.04 14.32 62.84 15.01 48.51 112.79 31.26 330.42 vb-01-09m 5.2 1 31.49 12.88 20.72 32.22 85.87 17.37 50.62 115.29 15.74 382.2 vb-01-09n 6.4 2 430.7 36.34 46.67 37.57 41.56 4.73 12.57 18.45 3.48 632.07 vb-01-090 6.7 2 216.03 63.23 54.3 35.82 59.36 10.58 35.8 52.56 3.64 531.32 vb-01-090 7.0 2 100.41 60.74 67.36 36.26 53.6 8.07 29.02 39.32 6.97 401.75 vb-01-09a 7.3 2 220.96 40 73.99 119.64 153.2 5.6 9 14.69 2.26 639.34 vb-01-09r 7.6 3 0 0 0 0.08 2.57 3.84 182.39 137.77 7.43 334.08 vb-01-09s 7.9 3 0.05 0.38 0.2 1.23 5.74 2.65 155.41 194.69 2.85 363.2 vb-01-09t 8.2 3 0.2 0.12 0.19 1.05 8.59 2.97 44.62 287.86 8.72 354.32 vb-01-09u 8.5 4 0 0 0.15 14.26 213.02 30 72.54 74.87 5.42 410.26 vb-01-09v 8.8 4 0 0 0.14 6.86 167.21 55.56 118.03 51.26 3.65 402.71 vb-01-09w 9.2 4 1.06 1.24 1.04 6.26 158.16 46.45 113.53 53.65 2.96 384.35 vb-01-09x 9.5 4 0 0 0.1 3.15 275.68 50.17 54.23 9.51 1.05 393.89 vb-01-09y 9.8 4 0 0 0.01 0.88 245.43 57.5 79.25 14.8 0.69 398.56 vb-01-09z 10.1 4 0 0 0.02 5.22 235.7 46.66 63.04 31.95 2.8 385.39 vb-01-09aa 10.4 5 0.65 0.47 0.52 4.89 161.71 30.59 73.58 94.27 3.86 370.54 vb-01-09ab 10.7 5 0.32 0.39 0.37 4.6 51.97 8.92 80.31 216.51 9.64 373.03 vb-01-09ac 11.0 5. 0 0 0.01 0.03 1.91 1.13 76.82 267.96 12.07 359,.93 vb-01-09ad 11.1 5 0 0 0.01 0.02 5.45 18.63 290.97 68.99 5.41 389.48 vb-01-09ae 11.3 5 0 0 0.82 1.81 4.49 7.12 109.43 82.83 3.94 210.44 vb-01-09af 11.6 5 0 0.55 0.41 6.8 154.44 34.09 128.11 147.52 6.58 478.5 vb-01-09ag 11.9 5 0 0 0.02 0.04 3.45 6.52 187.42 176.9 14.51 388.86 vb-01-09ah 12.2 5 0 0 0.05 0.21 3.03 2.52 158.54 215.37 11.23 390.95 vb-01-09ai 12.5 5 0 0.21 2.23 7.76 37.39 28.28 341.26 127.73 6.13 550.99 vb-01-09ai 12.8 5 0 0.05 0.25 1.05 23.76 18.83 197.06 148.57 12.17 401.74 vb-01-09ak 13.1 5 0 0 0.01 0.04 4.89 12.18 235.81 130.58 10.83 394.34 vb-01-09al 13.4 5 0 0 0 0.06 2.09 4.15 193.34 204.88 11.24 415.76 vb-01-09am 13.7 5 0 0 0.08 0.17 2.37 2.1 111.12 269.84 14.78 400.46 vb-01-09an 14.0 5 0.08 0.03 0.06 0.21 1.33 0.43 98.93 295.94 14.9 411.91 _. _. -..J sample depth (ml unit sieve 5 sieve 10 sieve 20 sieve 40 sieve 80 sieve 100 sieve 230 silt clay total wt vb-01-09ao 14.3 5 0 0.04 0.03 0.13 4.58 1.58 126.65 243.36 11.78 388.15 vb-01-09ap 14.6 5 0.11 0 0.02 0.14 4.4 1.91 101.63 276.54 11.06 395.81 vb-01-09aq 14.9 5 0 0.08 0.02 0.07 11.92 5.85 183.5 164.51 9.75 375.7 vb-01-09ar 15.3 5 0.56 0 0.02 0.01 0.82 1.06 97.89 218.84 9.76 328.96 vb-01-09as 15.6 5 0 0 0 0.03 6.16 3.05 94.77 205.06 7.75 316.82 vb-01-09at 15.9 5 0 0 0.01 0.15 0.8 0.46 65.96 222.25 16.37 306 vb-01-09au 16.2 5 0.34 0 0.1 0.12 1.19 0.62 84.11 209.83 9.71 306.02 vb-01-09av 16.5 5 0 0 0.01 0.13 9.75 5.47 83.33 218.58 10.19 327.46 vb-01-09aw 16.8 5 0 0 0.01 0.04 85.34 33.72 98.23 120.5 14.66 352.5 vb-01-09ax 17.1 5 0 0 0.01 0.22 89.16 35.13 114.67 92.2 5.46 336.85 vb-01-09ay 17.4 5 0 0.47 0.5 5.5 130.1 36.5 67.59 91.5 3.35 335.51 vb-01-09az 17.7 5 0.17 0.14 0.18 2.62 93.44 26.02 85.25 113.77 5.86 327.45 vb-01-09ba 18.0 5 0.18 0.04 0.03 0.24 110.9 45.63 77.9 75.2 3.74 313.86 vb-01-09bb 18.3 5 0 0 0.05 0.79 116.38 40.72 101.52 70.41 5.27 335.14 vb-01-09bc 18.6 5 0 0 0.02 0.06 15.68 24.83 235.12 76.37 7.54 359.62 vb-01-09bd 18.9 5 0 0 0.03 0.13 40.6 29.71 154.59 103.28 9.25 337.59 vb-01-09be 19.2 5 1.92 1.46 1.06 5.07 115.11 33.04 86 87.8 4.46 335.92 vb-01-09bf 19.5 5 0 0 0.05 0.1 7.52 6.18 123.03 181.08 9.23 327.19 vb-01-09bg 19.8 5 1.1 0.83 0.76 2.76 89.05 32.44 116.45 86.55 6.8 336.74 vb-01-09bh 20.1 5 0 0.13 0.03 0.09 13.74 7.83 108.61 168.17 11.88 310.48 vb-01-09bi 20.4 6 0 0 0 0.36 174.33 47.28 75.77 39.25 3.3 340.29 vb-01-09bj 20.7 6 0 0 0.04 1.27 166.79 48.03 87.73 50.06 2.37 356.29 vb-01-09bk 21.0 6 0.11 0 0.03 0.02 17.88 18.01 171.76 114.79 7.4 330 vb-01-09bl 21.4 6 0 0.02 0.04 0.97 148.13 45.15 84.35 51.74 4.92 335.32 vb-01-09bm 21.7 6 0 0 0 0.2 107.29 41.6 111.33 68.54 5.35 334.'31 vb-01-09bn 22.0 6 0 0 0 0.25 116.02 42.17 106.74 62.4 5.68 333.26 vb-01-09bo 22.3 6 0 0 0 0.02 103.99 59.24 98.86 66.02 7.92 336.05 vb-01-09bp 22.6 6 0.15 0.43 0.17 2.03 163.08 47.45 85.21 46.18 4.53 349.23 vb-01-09bq 22.9 6 0 0.04 0.02 0.05 7.73 13.32 196.15 110.33 13.2 340.84 vb-01-09br 23.2 6 0 0 0.02 5.33 232.39 39.35 50.28 10.9 1.7 339.97 vb-01-09bs 23.5 6 0 0 0.01 0.49 145.19 72.35 111.22 20.7 2.33 352.29 vb-01-09bt 23.8 6 0 0 0.02 4.26 167.75 39.79 68.14 43.78 4.71 328.45 vb-01-09bu 24.1 6 0 0 0.01 1.24 122.43 52.22 115.01 64.01 4.67 359.59 vb-01-09bv 24.4 6 0 0.08 0.1 5.59 186.45 34.65 59.49 49.87 2.46 338.69 vb-01-09bw 24.7 6 0 0 0.06 3.91 126.39 48.58 99.94 49.4 3.31 331.59 -QO sample depth (ml unit sieve 5 sieve 10 sieve 20 sieve 40 sieve 80 sieve 100 sieve 230 silt clay total wt vb-01-09bx 25.0 6 0 0 0.02 10.62 191.67 46.44 78 14.87 1.69 343.31 vb-01-09by 25.3 6 0 0 0 0.68 107.34 49.65 116.01 57.22 5.3 336.2 vb-01-09bz 25.6 6 0 0 0.56 35.06 191.98 24.04 45.41 63.16 3.37 363.58 vb-01-09ca 25.9 6 0.55 0.62 0.5 5.62 160.25 45.53 80.93 36.84 4.18 335.02 vb-01-09cb 26.2 6 0 0 0.1 25.28 255.5 29.99 29.96 7.54 1.48 349.85 vb-01-09cc 26.5 6 0 0 0.02 0.85 82.99 61.56 161.21 37.36 1.62 345.61 vb-01-09cd 26.8 6 0 0 0.02 5.09 163.72 46.08 94.17 33.63 3.14 345.85 vb-01-09ce 27.1 6 0 0 0.01 0.14 36.16 40.52 215.93 47.36 4.61 344.73 vb-01-09cf 27.5 6 0.14 0.23 0.13 8.79 153.86 38.64 82.93 55.73 4.53 344.98 vb-01-09ca 27.8 6 0 0 0.01 0.17 89.93 71.92 167.8 14.99 1.46 346.28 vb-01-09ch 28.1 6 0 0 0.08 16.91 212.65 43.3 67.74 12.19 1.29 354.16 vb-01-09ci 28.4 6 0 0.08 6.05 51.03 173.83 28.09 46.99 30.65 3.79 340.51 vb-01-09cj 28.7 6 0 0.05 5.17 33.75 123.73 33.71 102.64 56.2 3.9 359.15 vb-01-09ck 29.0 6 0.41 0.47 3.58 30.96 157.99 35.18 73.6 50.5 2.38 355.07 vb-01-09cl 29.3 6 0 0.22 9.24 53.92 187.03 27.94 45.3 24.52 3.66 351.83 vb-01-09cm 29.6 6 0 0.03 1.7 40.71 226.2 29.68 42.62 16.98 1.86 359.78 vb-01-09cn 29.9 6 0 0 1.5 38.91 210.92 28.37 43.44 26.92 3.26 353.32 vb-01-09co 30.2 6 0.35 0.35 2.62 30.85 157.9 25.82 51.46 82.83 4.7 356.88 vb-01-09co 30.5 6 0 0.06 2.76 41.88 206.29 28.6 42.94 25.28 3.22 351.03 vb-01-09ca 30.8 6 0.12 0.17 0.86 6.55 46.53 21.28 116.56 148.55 11.96 352.58 vb-01-09cr 31.1 6 4.42 0.76 1.07 1.01 18.31 22.56 228.45 140.22 8.77 425.57 vb-01-09cs 31.4 6 0 0 0.06 1.22 97.62 60.3 163.91 41.64 2.4 367.15 vb-01-09ct 31.7 6 0 0 0.03 0.88 81.01 53.92 163.52 46.03 2.6 347.99 vb-01-09cu 32.0 6 0 0.1 0.17 2.47 112.84 44.9 123.13 37.28 2.35 323,24 vb-01-09cv 32.3 6 0 0 0.07 • 2.45 142.59 49.99 131.19 35.1 2.68 364.07 vb-01-09cw 32.6 6 0 0 0.05 6.8 213.33 44 91.99 27.18 2.12 385.47 vb-01-09cx 32.9 6 0 0 0.03 13.66 286.74 37.29 56.3 24.1 1.95 420.07 vb-01-09cv 33.2 7 0 0 0.02 0.15 7.46 2.12 161.42 172.17 3.69 347.03 vb-01-09cz 33.6 7 0 0 0.01 0.08 172.46 65.58 104.79 26.93 1.51 371.36 vb-01-09da 33.9 7 0 0 0.01 0.02 5.37 13.43 200.98 131.37 5.95 357.13 vb-01-09db 34.2 7 0 0 0 0.01 0.7 0.29 117.63 229.86 9.36 357.85 vb-01-09dc 34.5 7 0 0 0.03 0.04 0.18 1.77 188.44 153.34 5.5 349.3 vb-01-09dd 34.8 7 0 0 0.01 0.04 0.47 3.45 197.18 140.98 7.25 349.38 vb-01-09de 35.1 7 0 0 0.02 0.09 12.48 14.53 141.25 153.31 6.91 328.59 vb-01-09df 35.4 7 0 0 0.03 0.13 6.69 8.27 135.46 172.08 7.92 330.58 - sample depth (ml unit sieve 5 sieve 10 sieve 20 sieve 40 sieve 80 sieve 100 sieve 230 silt clay total wt vb-01-09dg 35.7 7 0 0 0.02 0.01 1.97 7.07 218.38 117.85 6.11 351.41 vb-01-09dh 36.0 7 0 0 0.02 0.02 0.9 2.07 43.8 255.07 21.02 322.9 vb-01-09di 36.3 7 0 0.05 0.01 0.05 0.97 1.24 144.55 174.25 8.68 329.8 vb-01-09dj 36.6 8 1.26 1.36 0.99 2.26 65.4 33.36 175.35 82.69 5.13 367.8 vb-01-09dk 36.9 8 0 0.02 0.24 0.27 3.59 10.88 287.84 40.39 0.95 344.18 vb-01-09dl 37.2 8 0 0.03 0.24 0.53 1.89 4.35 246.15 66.87 3.17 323.23 vb-01-09dm 37.5 8 0 0.02 0.05 0.05 17.89 44.78 252.05 23.72 2.36 340.92 vb-01-09dn 37.8 8 0.52 0.47 0.77 0.9 21.33 43.59 229.59 31.12 3.39 331.68 vb-01-09do 38.1 8 0.1 0.08 0.21 0.51 43.43 66.18 182.51 31.22 3.79 328.03 vb-01-09dp 38.4 9 22.69 6.7 9.28 20.43 95.67 22.16 62.6 146.78 17.28 403.59 vb-01-09dQ 38.7 9 18.92 6.52 9.2 24.91 119.36 27.95 76.79 154.07 20.79 458.51 vb-01-09dr 39.3 9 14 4.34 5.24 15.61 82.25 20.08 56.11 168.37 23.2 389.2 vb-01-09ds 40.0 9 37.93 4.53 5.42 11.04 46.5 12.24 48.24 194.09 30.9 390.89 vb-01-09dt 40.6 9 5.37 5.92 6.85 12.52 50.3 13.11 51.4 203.66 28.17 377.3 vb-01-09du 41.2 9 20.69 6.29 7.39 11.47 46.14 12.21 48.86 213.03 36.22 402.3 vb-01-09dv 41.5 9 20.74 6.44 6.54 11.44 47.15 12.99 52.3 192.14 38.04 387.78 vb-01-09dw 41.8 10 12.46 11.74 16.3 98 216.09 15.6 22.11 28.72 5.42 426.44 vb-01-09dx 42.7 10 57.05 12.6 16.54 112.65 222.18 9.38 12.73 18.8 4.4 466.33 vb-01-09dy 43.0 10 0.52 1.44 13.2 107.6 225.47 13.62 22.19 26.81 3.78 414.63 vb-01-09dz 43.3 10 10.44 22.18 37.57 112.59 251.91 20.38 30.56 41.53 5.3 532.46 vb-01-09ea 43.6 10 46.81 11.62 18.64 109.41 198.31 13.86 27.49 70.45 5.7 502.29 vb-01-09eb 43.9 10 15.74 7.47 17.08 94.16 211.91 22.11 25.94 28.5 4.63 427.54 vb-01-09ec 44.2 10 0.59 7.4 28.56 235.6 150.87 2.66 5.41 13.83 4.05 448.97 vb-01-09ed 44.5 10 72.84 11.73 17.02 90.75 219.72 14.01 26.63 49.52 7.14 509.36 vb-01-09ee 44.8 10 2.73 3.21 15.36 108.99 272.86 14.25 22.82 34.93 6.43 481.58 vb-01-09ef 45.1 11 0 0.04 0.91 74.92 323.75 8.09 10.44 13.15 2.9 434.2 vb-01-09eg 45.4 11 0 0 0.02 49.8 300.28 7.83 14.01 23.81 2.29 398.04 vb-01-09eh 45.8 11 0 0.06 0.36 89.07 266.69 5.79 8.6 11.88 2.87 385.32 vb-01-09ei 46.1 11 0 0.06 1.84 115.65 241.59 4.35 5.72 8.12 2.22 379.55 vb-01-09ei 46.4 11 0 0.38 3.99 111.28 245 4.97 5.96 5.86 1.72 379.16 vb-01-09ek 46.7 11 0 0.29 2.77 86.99 269.12 8.11 7.79 5.04 0.87 380.98 vb-01-09el 47.0 11 0.26 0.32 4.82 92.09 244.14 9.57 9.25 6.48 1.68 368.61 vb-01-09em 47.3 11 0 0 0.15 27.71 283.4 16.9 18.38 12.47 2.8 361.81 vb-01-09en 47.6 11 0 0.02 0.28 34.53 284.36 13.83 14.94 16.52 2.94 367.42 vb-01-09eo 47.9 11 0.28 0.19 1.42 50.04 264.45 11.99 12.06 12.04 2.48 354.95 sample depth(ml unit sieve 5 sieve 10 sieve 20 sieve 40 sieve 80 sieve 100 sieve 230 silt clay totalwt vb-01-09ep 48.2 11 0 0 0.03 4.12 192.63 47.2 63.74 14.93 2.37 325.02 vb-01-09ea 48.5 11 0 0 0.14 15.92 247.29 20.24 45.98 36.59 4.02 370.18 - sample depth (m) unit sieve 10 sieve 18 sieve 36 sieve 60 sieve 120 sieve 230 silt clay total wt VB-02-01A 0.9 1 20.51 10.04 20.2 69.49 68.48 36.68 150.07 33.29 408.76 VB-02-018 1.5 2 1.6 3.37 33.4 247.08 69.32 7.14 9.69 4.25 375.85 VB-02-01C 2.1 2 0.04 0.09 3.42 235.42 110.92 36.59 6.65 6.12 399.25 VB-02-01D 2.7 3 123.75 50.07 113.43 180.88 49.07 5.82 7.73 1.34 532.09 VB-02-01E 3.4 3 189.27 53.5 98.66 113.71 18.36 3.89 7.43 1.12 485.94 VB-02-01F 4.0 3 153.23 64.62 194.39 161.94 22.66 6.35 13.14 2.1 618.43 VB-02-01G 4.6 3 65.42 32.07 89.34 197.15 43.27 19.9 43.21 7.83 498.19 VB-02-01H 5.2 3 211.72 53.47 98.14 134.93 64.51 20.32 29.05 5.05 617.19 VB-02-01I 5.8 4 26.81 14.72 131.13 306.82 31.12 3.09 5.53 1.64 520.86 VB-02-01J 6.7 4 38.48 8.12 128.99 362.71 29.13 5.29 8.49 2.96 584.17 VB-02-01K 7.6 4 7.98 11.48 47.11 207.39 206.62 27.91 21.73 3.43 533.65 VB-02-01L 8.2 4 3.84 1.65 28.46 323.9 122.91 15.54 23.2 5.65 525.15 VB-02-01M 8.8 4 3.08 1.06 50.63 275 86.33 22.42 56.87 13.49 508.88 VB-02-01N 9.5 5 0.33 0.89 31.68 347.04 49.52 10.36 20.01 4.67 464.5 VB-02-01O 10.1 5 0.7 0.34 15.97 326.22 108.26 7.91 6.66 1.41 467.47 VB-02-01P 10.7 5 0.18 0.53 34.54 251.16 91 9.99 10.16 1.95 399.51 VB-02-01Q 11.3 5 0.14 0.29 1.92 129.35 241.56 41.04 11.26 2.46 428.02 VB-02-01R 12.2 5 0.19 0.18 1.22 194.79 177.41 19.09 9.14 2.15 404.17 VB-02-01S 13.4 5 2.34 2.6 43.33 229.45 123.07 12.13 12.8 2.38 428.1 VB-02-01T 14.3 5 0.12 0.07 10.65 310.79 88.91 6.3 5.02 1.19 423.05 VB-02-01U 15.3 5 0.27 0.38 19.76 229.87 137.68 10 9 1.97 408.93 VB-02-01V 16.2 5 0.79 2.12 41.26 359.4 107.7 18.63 40.1 6.97 576.97 VB-02-01W 17.1 5 0.01 0.25 11.39 198.95 255.92 11.55 5.06 0.81 483.94 VB-02-01X 17.7 5 0.16 0.53 5.05 243.84 187.12 10.24 15.07 3.1 465.11 VB-02-01Y 18.6 6 59.04 18.12 33.9 227.38 147.73 20.88 34.63 5.36 547.04 VB-02-012 19.2 6 18.07 15.32 42.46 210.63 108.29 11.5 15.62 2.64 424.53 VB-02-01AA 19.8 6 12.87 5.74 37.37 162.96 113.05 6.94 8.34 0.5 347.77 VB-02-01AB 20.4 7 147.41 7.4 15.87 52.37 52.18 38.5 262.95 19.8 596.48 VB-02-01AC 21.0 7 68.42 12.81 33.14 98.89 114 35.06 120.88 7.67 490.87 VB-02-01AD 21.7 7 66.15 22.15 61.38 123.75 83.99 40.49 47.86 7.26 453.03 VB-02-01AE 22.3 7 265.29 57.4 99.81 53.88 32.11 9.69 16.86 2.87 537.91 VB-02-01AF 22.9 7 11.86 5.05 32.2 206.19 201.8 46.86 63.17 9.25 576.38 VB-02-01AG 23.5 7 13.18 3.7 8.13 32.53 79.7 82.29 259.95 22.05 501.53 VB-02-01AH 24.1 7 50.85 19.8 37.06 146.37 167.92 72.58 168.49 19.31 682.38 VB-02-01AI 24.7 7 13.07 6.7 19.75 77.7 92.18 26.48 157.75 22.44 416.07 N N sample depth (ml unit sieve 10 sieve 18 sieve 35 sieve 60 sieve 120 sieve 230 sllt clay total wt VB-02-01AJ 25.3 7 111.26 9.18 21.92 81.91 95.03 21.07 144.42 11.09 495.88 VB-02-01AK 25.9 7 47.81 19.82 41.23 116.65 107.69 49.77 133.51 17.44 533.92 VB-02-01AL 26.5 8 3.63 1.47 11.9 365.84 60.22 5.57 1.91 0.59 451.13 VB-02-01AM 27.5 8 0.19 0.31 22.61 401.73 58.45 3.83 2.31 0.74 490.17 VB-02-01AN 28.4 8 6.93 5.21 99.27 338.06 32.06 5.85 4.32 0.85 492.55 VB-02-01AO 29.3 8 4.48 3.2 38.68 340.82 73.44 6.67 9.59 1.73 478.61 VB-02-01AP 30.2 8 10.49 8.56 90.6 337.01 27.8 2.21 1.51 0.55 478.73 VB-02-01AQ 31.4 8 21.77 11.35 73 392.2 38.57 4 1.87 0.8 543.56 VB-02-01AR 32.6 8 0.08 0.03 2.53 377.45 186.67 6.2 0.63 0.5 574.09 VB-02-01AS 33.6 8 0.05 0.11 1.83 324.31 178.75 4.6 1.97 0.5 512.12 N w sample depth (m) unit sieve 10 sieve 18 sieve 35 sieve 80 sieve 120 sieve 230 sllt clav total wt VB-02-02A 1.5 1 29.53 3.08 8.73 30.46 44.26 49.85 172.83 33.58 372.32 VB-02-028 2.1 1 7.9 2.53 4.55 23.3 46.35 84 170.95 31.79 371.37 VB-02-02C 3.1 2 0.12 0.09 0.36 7.08 254.86 111.26 28.96 3.07 405.8 VB-02-02D 3.7 2 0.16 0.11 0.34 1.37 74.3 231.71 97.64 4.99 410.62 VB-02-02E 4.3 2 0.77 0.91 1.47 18.57 292.75 92.77 8.25 0.86 416.35 VB-02-02F 4.9 2 0.01 0.01 0.01 0.05 1.43 66.63 311.58 6.93 386.65 VB-02-02G 5.8 3 219.49 7.9 5.55 3.24 10.23 66.25 241.53 13.47 567.66 VB-02-02H 6.4 3 53.74 3.2 2.1 1.67 4.04 164.85 196.33 7.65 433.58 VB-02-021 7.0 3 120.19 1.04 0.78 0.51 3.91 148.92 171.85 7.82 455.02 VB-02-02J 7.6 4 0.01 0.01 0.01 36.33 300.08 123.54 17.86 0.83 478.67 VB-02-02K 8.2 4 0 0 0.02 8.75 306.97 152.38 9.7 0.7 478.52 VB-02-02L 8.8 4 0 0.01 0.01 11.05 313.19 110.82 11.88 0.77 447.73 VB-02-02M 9.8 4 0 0 0.01 6.55 326.47 150.77 10.43 0.64 494.87 VB-02-02N 10.7 4 0 0 0.03 3.06 407.65 75.91 7.93 0.75 495.33 VB-02-02O 11.3 4 0 0.03 0.02 6.73 312.62 138.42 4.48 0.54 462.84 VB-02-02P 11.9 4 0.02 0.02 0.15 43.52 390.97 47.44 7.91 0.82 490.85 VB-02-02Q 12.8 4 0 0.02 0.11 35.82 371.06 52.64 10.07 0.83 470.55 VB-02-02R 13.7 4 0.06 0.15 0.4 35.19 352.73 51.07 7.63 0.8 448.03 VB-02-02S 14.3 4 0.02 0.15 1.62 134.34 343.49 18.47 2.84 0.42 501.35 VB-02-02T 15.3 4 0 0.03 0.35 110.92 344.82 17.83 2.18. 0.4 476.53 VB-02-02U 15.9 4 0.03 0.06 0.57 100.59 363.96 15.09 0.4 0.5 481.2 VB-02-02V 16.2 5 23.52 16.87 40.08 289.85 139.2 8.52 4.43 1.74 524.21 VB-02-02W 16.8 5 4.88 4.04 11.22 101.48 247.2 59.04 8.72 3.5 440.08 VB-02-02X 17.4 6 0 0.02 0.28 0.8 12.96 208.6 226.72 5.31 .454.69 VB-02-02Y 18.0 6 0 0.02 0.15 0.98 44.77 246.23 138.17 4.17 434.49 VB-02-022 18.6 6 0 0.03 0.06 0.72 135.28 258.17 87.32 1.46 483.04 VB-02-02AA 19.2 6 0.25 0.19 0.25 10.11 388.89 65.6 5.04 0.5 470.83 VB-02-02AB 19.8 6 0 0.06 0.12 1.17 217.75 204.22 12.47 0.7 436.49 VB-02-02AC 20.4 6 0 0.04 0.15 2.1 132.57 234.92 64.95 1.4 436.13 VB-02-02AD 21.0 6 0 0 0.02 0.03 35.1 257.78 204.04 3.11 500.08 VB-02-02AE 21.7 6 0 0.02 0.98 11.75 29.08 63.35 312.45 11.47 429.1 VB-02-02AF 22.3 6 0 0 0.04 0.47 123.73 218.36 28.83 1.13 372.56 VB-02-02AG 22.9 6 0 0.06 0.16 0.98 142.01 225.22 29.89 1.45 399.77 VB-02-02AH 23.5 6 0 0 0.03 1.2 171.84 189.1 28.19 1.22 391.58 VB-02-02AI 24.4 6 0 0.01 0.03 0.28 171.04 241.36 16.04 0.75 429.51 -tv � samole deoth fm) unit sieve 10 sieve 18 sieve 35 sieve 60 sieve 120 sieve 230 silt clav total wt VB-02-02AJ 25.0 7 9.93 0.08 0.49 6.63 8.86 5.27 176.43 116.65 324.34 VB-02-02AK 25.9 7 0 0.03 0.21 1.85 10 4.38 406.91 8.63 432.01 VB-02-02AL 26.5 8 29.6 6.11 8.01 19.12 19.67 15.99 248.34 35.11 381.95 VB-02-02AM 27.8 8 34.27 6.05 10.74 34.49 44.31 16.74 225.11 32.97 404.68 VB-02-02AN 29.0 8 112.88 5.59 8.19 30.71 36.41 24.98 173.54 16.45 408.75 sample depth (m) unit sieve 10 sieve 18 sieve 35 sieve 60 sieve 120 sieve 230 sllt clay total wt VB-02-03A 1.2 1 17.54 3.14 5.19 19.66 25.76 24.53 195.31 101.74 392.87 VB-02-03B 2.1 1 17.41 5.25 9.85 31.81 42.49 9.07 209.02 66.13 391.03 VB-02-03C 3.1 1 20.62 4.69 8.28 30.96 41.09 33.18 261.84 28.22 428.88 VB-02-03O 4.0 1 20.75 6.23 11.49 37.04 54.44 21.74 311.55 19.32 482.56 VB-02-03E 4.6 1 24.77 4.98 8.91 34.6 44.62 34.66 265.32 29.37 447.23 VB-02-03F 6.1 1 17.56 6.34 11.34 38.64 57.33 1.8 291.95 83.13 508.09 VB-02-03G 7.3 1 6.72 3.57 6.85 31.22 63.54 59 228.55 105.66 505.11 VB-02-03H 8.5 1 8.2 4.7 9.41 35.98 63.58 48.08 223.58 97.82 491.35 VB-02-03I 9.8 1 6.79 1.19 6.5 28.18 40.02 36.95 280.05 31.79 431.47 VB-02-03J 11.0 1 26.1 12.32 23.27 65.04 66.96 27.45 225.43 16.23 462.8 VB-02-03K 11.9 1 17.65 6.01 10.28 35.74 45.97 36.98 228.04 40.52 421.19 VB-02-03L 12.8 1 17.61 7.9 12.26 36.01 48.29 32.46 241.38 45.59 441.5 VB-02-03M 14.0 1 9 4.71 7.64 21.23 27.43 0.64 264.14 66.82 401.61 VB-02-03N 14.9 1 80.76 12.45 16.42 58.72 71.63 38.69 168.36 20.22 467.25 VB-02-03O 16.2 1 14.97 4.12 7.09 22.47 33.73 20.62 309.49 12.83 425.32 VB-02-03P 17.4 1 6.59 2.74 7.8 44.86 71.3 52.04 207.99 34.95 428.27 VB-02-03Q 18.9 1 14.6 5.53 8.91 21.5 28.44 14.16 294.14 52.68 439.96 VB-02-03R 20.1 1 93.49 3.55 4.02 11.09 14.51 16.26 199.93 22.07 364.92 VB-02-03S 21.4 1 5.34 3.36 4.12 11.22 13.77 17.9 164.23 214.51 434.45 VB-02-03T 22.6 1 43.56 15.2 27.14 105.58 132.49 51.44 107.84 6.2 489.45 VB-02-03U 23.2 1 50.11 16.5 23.59 76.33 91.79 60.29 180.12 10.53 509.26 VB-02-03V 23.8 1 53.8 11.78 18.86 54.26 70.79 31.69 163.64 25.09 429.91 VB-02-03W 24.7 1 4.69 2.35 2.78 7.38 9.19 10.33 291.2 75.92 403.84 VB-02-03X 25.6 1 127.6 9.17 9.67 25.56 41.11 90.42 180.6 13.38 . 497.51 VB-02-03Y 26.2 2 0.15 0.69 11.21 134.96 158.7 76.87 161.71 12.38 556.67 VB-02-032 26.8 3 0.29 0.21 0.97 5.05 5.77 4.69 252.05 175.64 444.67 VB-02-03AA 27.8 3 0.01 0.01 0.02 0.05 0.18 0.71 392.85 7.83 401.66 VB-02-03AB 28.4 3 0 0 0.11 8.47 231.88 167.91 33.98 1.78 444.13 VB-02-03AC 28.7 4 0 0 0.71 277.41 89.57 84.5 17.63 1.15 470.97 VB-02-03AD 29.3 4 0.01 0.01 0.06 365.22 83 10.01 7.91 1.66 467.88 VB-02-03AE 29.4 5 0.12 0.05 0.05 0.23 0.33 0.33 221.35 150.08 372.54 VB-02-03AF 29.9 6 20 8.48 11.69 27.43 34.43 27.45 275.08 29.26 433.82 VB-02-03AG 30.5 6 148.68 8.31 8.57 20.96 28.93 13.96 169.76 15.31 414.48 VB-02-03AH 31.4 6 17.46 6.85 10.56 29.16 34.9 41.57 248.9 28.68 418.08 VB-02-03AI 32.3 6 14.48 5.31 8.29 19.3 22.87 7.79 255.71 58.3 392.05 AppendixB X-rayDiffraction Results 127 128 sample stratigraphic position 7/10 ratio 14/10(315 C) 14/10 (20 C) till unit VB-01-09A upper diamicton 0.840 0.148 0.298 Saugatuck VB-01-098 uccer diamicton 1.028 0.163 0.324 Saugatuck VB-01-09C uccer diamicton 0.735 0.127 0.191 Saugatuck VB-01-09O upper diamicton 0.426 0 0.21 Saugatuck VB-01-09G uccer diamicton 0.321 0 0.164 Saugatuck VB-01-09H uccer diamicton 0.392 0 0.255 Saugatuck VB-01-09I upper diamicton 0.309 0 0.185 Saugatuck VB-01-09J upper diamicton 0.794 0.138 0.213 Saugatuck VB-01-09K upper diamicton 0.908 0.122. 0.262 Saugatuck VB-01-09L upper diamicton 0.364 0 0.118 Saugatuck VB-01-09M upper diamicton 0.364 0 0.182 Saugatuck VB-01-09N lacustrine 0.625 VB-01-09O lacustrine 0.467 VB-01-09P lacustrine 0.579 VB-01-09Q lacustrine 0.577 VB-01-09R lacustrine 0.500 VB-01-09S lacustrine 0.333 VB-01-09T lacustrine 0.405 VB-01-09U lacustrine 0.438 VB-01-09W lacustrine 0.500 VB-01-09AH lacustrine 0.746 VB-01-09AI lacustrine 0.542 VB-01-09AJ lacustrine 0.455 VB-01-09AO lacustrine 0.581 VB-01-09AP lacustrine 0.508 VB-01-09AQ lacustrine 0.589 VB-01-09E lower diamicton 1.174 0.189 0.333 Ganges VB-01-09DP lower diamicton 0.890 0.145 0.238 Ganges VB-01-09DQ lower diamicton 0.852 0.148 0.271 Ganges VB-01-09DR lower diamicton 0.869 0.106 0.183 Ganges VB-01-09DS lower diamicton 0.986 0.083 0.268 Ganges VB-01-09DT lower diamicton 0.920 0.145 0.233 Ganges VB-01-09DU lower diamicton 0.935 0.129 0.296 Ganges VB-01-09DV lower diamicton 0.925 0.185 0.216 Ganges VB-01-07AA lacustrine 1.427 VB-01-07AB lacustrine 1.399 VB-01-07AC lacustrine 1.246 VB-01-07AH lacustrine 0.882 VB-01-07AI lacustrine 0.712 VB-01-07AJ lacustrine 0.661 VB-99-03O middle diamicton 0.684 0 0.234 Saugatuck VB-99-03P middle diamicton 0.639 0.081 0.217 Saugatuck VB-99-03Q middle diamicton 0.531 0 0.21 Saugatuck VB-99-03X lower diamicton 0.869 Ganges VB-02-01AB lower diamicton 0.365 0 0.164 Saugatuck VB-02-01AC lower diamicton 0.379 0.064 0.297 Saugatuck VB-02-01AF lower diamicton 0.328 0 0.102 Saugatuck 129 sample stratigraphic position 7/10 ratio 14/10 (315 C) 14/10 (20 C) till unit VB-02-01AG lower diamicton 0.441 0 0.13 Saugatuck VB-02-01AH lower diamicton 0.402 0.043 0.111 Saugatuck VB-02-01AI lower diamicton 0.469 0.037 0.149 Saugatuck VB-02-01AJ lower diamicton 0.543 0.019 0.27 Saugatuck VB-02-01AK lower diamicton 0.611 0 0.241 Saugatuck VB-02-02AL lower diamicton 0.942 0.048 0.28 Ganges VB-02-02AM lower diamicton 0.806 0.105 0.16 Ganges VB-02-02AN lower diamicton 0.688 0.023 0.143 Ganges VB-02-03A upper diamicton 0.792 ? VB-02-03B upper diamicton 0.412 ? VB-02-03C upper diamicton 0.304 ? VB-02-03D upper diamicton 0.500 ? VB-02-03E upper diamicton 0.520 ? VB-02-03F upper diamicton 0.727 ? VB-02-03G upper diamicton 0.788 ? VB-02-03H upper diamicton 0.586 ? VB-02-03I upper diamicton 0.707 ? VB-02-03J upper diamicton 0.659 ? VB-02-03K upper diamicton 0.600 ? VB-02-03L upper diamicton 0.742 ? VB-02-03M upper diamicton 0.922 ? VB-02-03N upper diamicton 0.508 ? VB-02-03O upper diamicton 0.344 ? VB-02-03P upper diamicton 0.714 ? VB-02-03O upoer diamicton 0.542 ? VB-02-03R upoer diamicton 0.646 ? VB-02-03S uooer diamicton 0.674 ? VB-02-03T upper diamicton 0.378 ? VB-02-03U upper diamicton 0.429 ? VB-02-03V upper diamicton 0.500 ? VB-02-03W upper diamicton 0.911 ? VB-02-03X upper diamicton 0.632 ? VB-02-03Y lacustrine 0.765 VB-02-032 lacustrine 1.000 VB-02-03AA lacustrine 0.543 VB-02-03AB lacustrine 0.409 VB-02-03AC lacustrine 0.467 VB-02-03AD lacustrine 0.319 VB-02-03AE lacustiine 0.985 VB-02-03AF lower diamicton 0.517 ? VB-02-03AG lower diamicton 0.406 ? VB-02-03AH lower diamicton 0.669 ? VB-02-03AI lower diamicton 0.981 ? AppendixC Stokes's Law 130 131 Stokes's Law Stokes's Law estimates settling velocities of small particles(< 0.1 - 0.2 mm) based on spherical particle diameter, viscosity of the fluid, and height. A simplified version of Stokes's Law is as follows: Equation 6. V = CIY(emfs) where Vis settlingvelocity (cm/s) C is a constant equal to (p. - Pr)g/18µ D is the diameter of sphere-shaped particles( cm) p. is the density of the particle(g/cm 3) 3 Pr is the density of the fluid(g/cm ) g is the acceleration of gravity ( cm/s2) µ is the viscosity of the fluid(g/s*cm) Values used for the silt-sized particle settlingvelocity calculation are as follows: D = 4µm = 3 Ps 2.65 g/cm PF 1.0 g/cm3 g = 980 cm/s2 µ = 0.01005 g/s*cm(20 ° C) 132 Using these values, a time of 116 minutes for silt-sized particles to settle in water froma height of 10 cm at a temperature of20° C is calculated. This calculation assumes that silt-sized particles are spherical. The settling velocity will decrease (and settling time will increase) as particle shapes become less spherical. The temperature used for this calculation, 20° C, is an underestimate of the actual temperature in the lab. A slightly higher temperature would result in an increase in settling velocity (and a decrease in settling time). Thus, two hours is a reasonable estimate for the time in which silt-sized particles will settle froma height of 10 cm. Values used for the coarse clay-sized particle settling velocity calculation are as follows: D=2µm Ps= 2.65 g/cm3 PF 1.0 g/cm3 g = 980 cm/s2 µ = 0.01005 g/s*cm (20° C) Using these values, a time of 7.76 hours is calculated for coarse clay-sized particles to settle in water froma height of 10 cm at 20° C. AppendixD Student's t-test 133 134 Student's t-test The student's t-test is a statistical test of two normally distributed populations to determine if their means are equal or not equal. For each population, at-value is calculated by means of the following equation (fromJensen et al., 1997): Equation 7. Where: XA is the mean of population A SA2 is the variance of population A IA is the number of samples of population A Since unequal variances is assumed, the degrees of freedom value for each comparison must be calculated by the following equation(from Jensen et al., 1997): Equation 8. 2 2 s_A_+_B_ s df =------IA 1B - S A 4 + SB 4 J/(JA -1) J/(JB -1) 135 The null hypothesis, Ho, states the means of the two populations being compared are equal. This hypothesis is accepted if the calculated t is less than t(a/2, dt), a value that is obtained from charts of tabulated t values, where a is the confidence level of the test. All calculations in this study were performed at the 95% confidencelevel (a=0.05). The null hypothesis is rejecte9 if the calculated tis greater than t(a/2, dt). This implies that the means are different beyond what could be expected from sampling variability at the given confidencelevel. 136 BIBLIOGRAPHY- 1., Benn, D. I., and Evans, J. A., 1998. Glaciers and glaciation. OxfordUniversity Press, London, 734 p. Bird, B. C., in preparation. Glacial stratigraphy and surficialgeology of the Decatur, Lawrence, and Paw Paw USGS 7.5 minute quadrangles, Van Buren County, Michigan. WesternMichigan University, Kalamazoo. Bird, B. C., Kozlowski, A. L., and Kehew, A. E., 2001. 3-D mapping of the Lawrence 7.5 minute quadrangle, Van Buren County, Southwest Michigan. Geological Societyof America Abstracts with Programs, Vol. 33, No. 6, p. 317. Bradley, R. S., 1999. Paleoclimatology: reconstructing climates of the Quaternary. 2nd ed., Prentice Hall, Upper Saddle River, New Jersey, 613 p. Boggs, S., 1995. Principles of Sedimentology and Stratigraphy. 2nd ed., Prentice Hall, Upper Saddle River, New Jersey, 774 p. Chamberlin: T. C., 1894. Glacial phenomena of North America. In Geikie, J., The Great Ice Age. Edward Stanford, London, 850 p. Colman, S. M., Clark, J. A., Clayton, L., Hansel, A. K., and Larsen, C. E., 1994. Deglaciation, lake levels, and meltwater discharge in the Lake Michigan Basin. QuaternaryScience Reviews, Vol. 13, p. 879-890. Dodson, R. L., 1993. Reinterpretation of the northwest portion of the Tekonsha Moraine, south-centralMichigan. Physical Geography, Vol. 14, No. 2, p. 139-153. /Dodson, R. L., 1985. Topographic and sedimentary characteristics of the Union Streamlined Plain and surrounding morainic areas. Ph.D. dissertation, Michigan State University, 169 p. ✓ Dorr, J. A., Jr., and Eschman, D. F., 1970. The Geology of Michigan. The University of Michigan Press, Ann Arbor, Michigan, 476 p. Dreimanis, A., 1977. Late Wisconsin glacial retreat in the Great Lakes region, North America. New York Academy ofSciences Annals, Vol. 288, p. 70-89. 137 Dworkin, S. I., Larson, G. J., and Monaghan, G. W., 1985. Late Wisconsinan ice-flowreconstruction forthe central Great Lakes region. Canadian Journal ofEarth Sciences, Vol. 22, p. 935-939. ;>( Flint, A. C., 1999. Stratigraphicanalysis of diamictonunits in north-central St. Joseph County, Michigan. Masters thesis, WesternMichigan University, Kalamazoo, 105 p. Fraser, G. S., and Bloom, N. K., 1991. Geologic framework of the aquifers of the Valparaiso moraine. Occasional Paper 59, Indiana Geological Survey, 8 p. �U-._,_k Fullerton, D. S., 1986. Stratigraphyand correlation of glacial deposits from Indiana to New York and New Jersey. QuaternaryScience Reviews, Vol. 5, p. 23-29. Gardner, R. C., 1997. Lithologic and stratigraphicanalysis of glacial diamictons, / Sturgis, Michigan. Masters thesis, WesternMichigan University, Kalamazoo, 101 p. Hansel, A. K., Mickelsen, D. M., Schneider, A. F., and Larsen, C. E., 1985. Late Wisconsinan and Holocene history of the Lake Michigan Basin. In Karrow, P. F. and Calkin, P. E., eds., QuaternaryEvolution ofthe Great Lakes. Geological Association of Canada Special Paper 30, p. 39.:54_ Jensen, J. L., Lake, L. W., Corbett, P. W. M., and Goggin, D. J., 1997. Statistics for Petroleum Engineers and Geoscientists. Prentice Hall PTR, Upper Saddle River, New Jersey, 390 p. Johnson, W. H., Hansel, A. K., Bettis, E. A., Karrow, P. F., Larson, G. J., Lowell, T. V., and Schneider, A. F., 1997. Late Quaternarytemporal and event classification, Great Lakes Region, North America. QuaternaryResearch, Vol. 47, No. 1, p. 1-12. Karrow, P. F., Dreimanis, A., and Barnett, P. J., 2000. A proposed diachronic revision of late Quaternarytime-stratigraphic classification in the easternand northernGreat Lakes area. QuaternaryResearch, Vol. 54, p. 1-12. ,;,----Kehew, A. E, Beukema, S. P., Bird, B. C., Kozlowski, A. L., Lee, J., 2002. Glacial terrainmap of Van Buren County, Michigan. Michigan Department of Environmental Quality. Kehew, A. E., Beukema, S. P., Bird, B. C., and Kozlowski, A. L., 2002. Stratigraphic Frameworkof the easternmargin of the Lake Michigan Lobe. Geological Societyof America Abstracts with Programs, Vol. 34, No. 6, p. 131. 138 Kehew, A. E., and Kozlowski, A. L., 2001. Glacial geology of Southwest Michigan: Landformsand sediments of the Lake Michigan Lobe, Southwestern Michigan. American Association ofPetroleum Geologists, EasternSection Meeting, Field trip guide, Kalamazoo, Michigan, Field Trip Guide Book, 32 p. Kehew, A. E., Bird, B. C., Kozlowski, A. L., Wong, S. A., and Beukema, S. P., 2001. Origin of the Valparaiso moraine,Van Buren County, Michigan. Geological Societyof America Abstracts with Programs, Vol, 33, No. 6, p. 268. Kehew, A. E., Bird, B. C., and Kozlowski, A. E., 2000. Geology and radiocarbon age ofa buried forestat the Moline Site in Southwestern Michigan. Geological Societyof America Abstracts with Programs, North Central Section Meeting, Vol. 32, No. 4, p.20. Kehew, A. E., Nicks, L. P., and Straw, W. T., 1999. Palimpsest tunnel valleys: evidence forrelative timing of advances in an interlobate area of the Laurentide ice sheet. Annals of Glaciology, Vol. 28, p. 47-52. Kehew, A. E., and Teller, J. T., 1994. History oflate glacial runoffalong the southwesternmargin ofthe Laurentide Ice Sheet. In Teller, J. T., and Kehew A. E., eds., Late glacial history of large proglacial lakes and meltwater runoff along the Laurentide Ice Sheet. QuaternaryScience Reviews, Vol. 13, p. 859- 878. Kozlowski, A. L., in preparation. The origin of the central Kalamazoo River Valley: relationships between ice dynamics, the Lake Michigan lobe, and the Saginaw lobe of the Laurentide Ice Sheet. Ph.D. dissertation, Western Michigan University, Kalamazoo. Kozlowski, A. L., Kehew, A. E., and Bird, B. C., 2001. An outburst hypothesis for the origin of the Kalamazoo River Valley, Kalamazoo and Allegan County, Michigan. Geological Societyof America Abstracts with Programs, Vol. 33, No. 6, p. 269. Kozlowski, A. L., 1999. Three dimensional mapping of the E�t Leroy and Union City 7.5 minute quadrangles in southwest Michigan. Masters thesis, Western Michigan University, Kalamazoo,113 p. Krumbein, W. C., and Pettijohn, F. J., 1938. Manual of Sedimentary Petrography. Appleton-Century-Crofts, Inc., New York, 549 p. Larson, G., and Schaetzl, R., 2001. Origin and evolution of the Great Lakes. Journal of Great LakesResearch, Vol. 27, No. 4, p. 518-546. 139 Leverett,F., and Taylor,F., 1915. The .Pleistoceneof Indiana and Michigan and the History of the Great Lakes. U.S. Geological Survey Monograph 53,527 p. Monaghan, G. W., 1990. Systematic variation in the clay-mineral composition of till Sheets; evidence for the Erie Interstade in the Lake Michigan basin. In Schneider, A. F., and Fraser, G. S., eds.,Late Quaternaryhistory of the Lake Michigan basin. Geological Societyof America Special Paper 251, p. 43-50. Monaghan,G. W.,Larson, G. J., and Gephart,G. D.,1986. Late Wisconsinan drift stratigraphyof the Lake Michigan Lobe in southwesternMichigan. Geological Societyof America Bulletin, Vol. 97, p. 329-334. Monaghan,G. W., and Larson,G. J., 1986. Late Wisconsinan driftstratigraphy of the Saginaw Ice Lobe in south-centralMichigan. Geological Societyof America Bulletin, Vol. 97, p. 324-328. Moore, D. M., and Reynolds,R. C., 1997. X-ray diffraction and the identification and Analysis of clay minerals. 2nd ed.,Oxford University Press,New York, 378 p. Nicks, L. P. Unpublished data, WesternMichigan University. Reineck,H. E., and Singh,I. B., 1975. Depositional Sedimentary Environments. Corrected Reprint of the First Edition, Springer-Verlag,New York,439 p. Rieck,R. L., 1993. Driftvolume in the southernpeninsula of Michigan: a prodigious Pleistocene endowment. PhysicalGeography, Vol. 14,No. 5, p. 478-493. Rieck,R. L., Winters, H. A., Mokma, D. L., and Mortland,M. M., 1979. Differentiation of surficial glacial driftin southeasternMichigan from7 All OA X-ray diffraction ratios in clays. Geological Societyof America, Part I,Vol. 90,p. 216-220. Rieck,R. L., 1976. The glacial geomorphology of an interlobate are in southeast Michigan: relationships between landforms,sediments, and bedrock. Ph.D. dissertation, Michigan State University, East Lansing,218 p. Ritter, D. F.,Kochel, R. C., and Miller,J. R., 1995. Process Geomorphology. 3rd ed., Wm. C. Brown Publishers,Dubuque, Iowa,546 p. Terwilliger, 1954. The glacial geology and groundwater resources of Van Buren County, Michigan. Occasional papers for 1954, Michigan State Geology Survey, 95 p. 140 Velde, B., 1992. Introduction to Clay Minerals: Chemistry, origins, uses and environmental significance. Chapman & Hall, New York, 198 p. Wayne, W. J., and Zumberge, J. H., 1965. Pleistocene geology of Indiana and Michigan. In The Quaternary of the United States, Princeton University Press, Princeton, New Jersey, p. 63-83. WesternMichigan University, Department of Geology, College of Arts and Science, 1981. Hydrogeologic Atlas of Michigan, Kalama,zoo, Plate 13. '/ Wong, S. A., 2002. StratigraphicAnalysis of diamicton units in southernAllegan County, Michigan. Masters thesis, WesternMichigan University, Kalamazoo, 63 p. Zumberge, J. H., 1960. Correlation of Wisconsinan driftsin Illinois, Indiana, Michigan, and Ohio. GeologicalSociety of America Bulletin, Vol. 71, p. 1177-1188.