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Sedimentology and Palynology of Middle Wisconsinan Deposits in the Pecatonica River Valley, Wisconsin and Illinois

Published online by Cambridge University Press:  20 January 2017

G. Richard Whittecar  and
Anthony M. Davis
G. Richard Whittecar
Affiliation:
Department of Geophysical Sciences, Old Dominion University, Norfolk, Virginia 23508
Anthony M. Davis
Affiliation:
Department of Geography, University of Toronto, Toronto, Canada M5S 1A1
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Abstract

The bedrock valley of the Pecatonica River north of Freeport, Illinois, contains a thick valley-fill complex of alluvium and drift. Within the valley, loess-capped benches surround hills of silty Illinoian drift. Beneath these benches lie thick deposits of poorly sorted stony silt interbedded with thin lenses of silt, sand, and organic-rich loam. Channel deposits and peat cap the diamicton in places. We interpret the stony silts as solifluction debris shed from silty slopes within the valley-fill during the Early or Middle Wisconsinan (Altonian). Top and bottom radiocarbon dates from a 2.5-m section of peat overlying the diamicton are 26,820 ± 200 and 40,500 ± 1700 yr B.P., respectively. We informally refer to the stony silts, channel sediments, and peat as the “Martintown unit.” Geomorphic position, sediment input, and macrofossils suggest that the dated peat was deposited in a floodplain pond (oxbow?). The pollen record from the peat indicates that a boreal forest dominated this area during the Middle Wisconsinan (late Altonian and Farmdalian). Two pollen zones are recognized: a basal Zone I with Pinus slightly more abundant than Picea and with few herbs and shrubs, and an upper Zone II dominated by Picea and with a larger representation of herbaceous and shrub taxa. Little displacement of vegetation zones is indicated, even though ice advanced to within 100 km of the site during the time of peat accumulation. Because of the problems involved in clearly defining Middle Wisconsinan forest-tundra in mid-latitudes by using analogs of Holocene forest-tundra in high latitudes, caution is required in making geomorphic inferences solely from vegetation data. Together, though, pollen and sediment data indicate that during the Middle Wisconsinan, Pecatonica hillslopes progressed through a sequence of instability-stability-instability related to climatic fluctuations.

Type
Research Article
Information
Quaternary Research , Volume 17 , Issue 2 , March 1982 , pp. 228 - 240
Copyright
University of Washington

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References

Allen, J.R.L. (1965). A review of the origin and characteristics of recent alluvial sediments. Sedimentology 5, 89–191.CrossRefGoogle Scholar
Allen, J.R.L. (1978). Fluvial sedimentation Fairbridge, R.W. Bourgeois, J. Encyclopedia of Sedimentology Dowden, Hutchinson, and Ross, Stroudsburg, PA. 335–337.Google Scholar
Baker, V.R. Penteado-Orellano, M.M. (1977). Adjustments to Quaternary climate change by the Colorado River in central Texas. Journal of Geology 85, 395–422.CrossRefGoogle Scholar
Beckett, S.C. (1979). Pollen influx in peat deposits: Values from raised bogs in the Somerset Levels, southwestern England. New Phytology 83, 839–847.CrossRefGoogle Scholar
Berti, A.A. (1975). Paleobotany of Wisconsin Interstadial, Eastern Great Lakes Region, North America. Quaternary Research 5, 591–616.CrossRefGoogle Scholar
Birks, H.J.B. (1973). Modern pollen rain studies in some arctic and alpine environments Birks, H.J.B. West, R.G. Quaternary Plant Ecology Blackwell, Oxford. 132–168.Google Scholar
Black, R.F. (1965). Ice-wedge casts of Wisconsin. Wisconsin Academy of Sciences, Arts and Letters 54, 187–222.Google Scholar
Bleuer, N.K. (1970). Glacial Stratigraphy of South-Central Wisconsin. Pleistocene Geology of Southern Wisconsin, (J-1 to J-35) Wisconsin Geological and Natural History Survey Information Circular 15.Google Scholar
Brown, R.J.E. (1969). Factors influencing discontinuous permafrost in Canada Pewe, T.L. The Periglacial Environment: Past and Present McGill-Queens University Press, Montreal. 11–53.Google Scholar
Bull, W.B. (1962). Relation of textural (CM) patterns to depositional environments of alluvial-fan deposits. Journal of Sedimentary Petrology 32, 211–217.Google Scholar
Davis, A.M. (1977). The prairie-deciduous forest ecotone in the upper Middle West. Assoc. Amer. Geogs. 67, 204–213.CrossRefGoogle Scholar
Dirlam, D.M. (1979). Pollen analysis of mid-Altonian peat in Schelke Bog, Lincoln County, Wisconsin. M.S. thesis University of Wisconsin-Madison.Google Scholar
Dreimanis, A. Karrow, P.F. (1972). Glacial history of the Great Lakes-St. Lawrence region, the classification of the Wisconsin(an) Stage and its correlatives. 24th International Geological Congress Report Section 12 5–15.Google Scholar
Faegri, K. Iversen, J. (1975)Textbook of Pollen Analysis Munksgaard, Copenhagen.Google Scholar
Fernald, M.L. 8th ed. 1950 Gray's Manual of Botany Van Nostrand, New York.Google Scholar
Fricke, C.A.P. (1976). The Pleistocene geology and geomorphology of a portion of central southern Wisconsin. M.S. thesis University of Wisconsin-Madison.Google Scholar
Grüger, E. 1972a. Pollen and seed studies of Wisconsin vegetation in Illinois. Geological Society of America Bulletin 83, 2715–2734.CrossRefGoogle Scholar
Grüger, E. 1972b. Late Quaternary vegetation development in south-central Illinois. Quaternary Research 2, 217–231.CrossRefGoogle Scholar
Hallberg, G.R. Baker, R.G. Legg, T. (1980). A mid-Wisconsinan pollen diagram from Des Moines County, Iowa. Proceedings, Iowa Academy of Science 87, 41–44.Google Scholar
Hare, F.K. (1976). Late Pleistocene and Holocene climates: Some persistent problems. Quaternary Research 6, 507–517.CrossRefGoogle Scholar
Janssen, C.R. (1973). Local and regional pollen deposition Birks, H.J.B. West, R.J. Quaternary Plant Ecology Blackwell, Oxford. 31–42.Google Scholar
Kapp, R.O. (1977). Late Pleistocene and postglacial plant communities of the Great Lakes region Romans, R.C. Geobotany Plenum, New York. 1–26.Google Scholar
Kempton, J.P. Hackett, J.E. (1968). Stratigraphy of the Woodfordian and Altonian drifts of central northern Illinois Bergstrom, R.E. The Quaternary of Illinois University of Illinois Press: College of Agriculture Special Publication 14 27–34.Google Scholar
Kempton, J.P. (1969). The late Altonian (Wisconsinan) glacial sequence in Northern Illinois Morrison, R.B. Wright, H.E. Jr. Means of Correlations of Quaternary Successions University of Utah Press, Salt Lake City. 525–546.Google Scholar
King, J.E. (1979). Pollen analysis of some Farmdalian and Woodfordian deposits Central Illinois Follmer, L.R. McKay, E.D. Lineback, J.A. Woodfordian, Sangamonian, and Illinoian Stratigraphy in Central Illinois 109–113Illinois State Geological Survey Guidebook 13.Google Scholar
Knox, J.C. (1980). Wisconsinan and Holocene valley deposits in the Wisconsin Driftless Area. Abstracts with Programs North-Central Section, Geological Society of America 231.Google Scholar
Leighton, M.M. Brophy, J.A. (1966). Farmdale glaciation in northern Illinois and southern Wisconsin. Journal of Geology 74, 478–499.CrossRefGoogle Scholar
McKay, E.D. (1979). Wisconsinan loess stratigraphy of Illinois Follmer, L.R. McKay, E.D. Lineback, J.A. Gross, D.L. Wisconsinan, Sangamonian, and Illinoian Stratigraphy in Central Illinois 95–108Illinois State Geological Survey Guidebook 13.Google Scholar
Mode, W.N. (1976). The glacial geology of a portion of north-central Wisconsin. M.S. thesis University of Wisconsin-Madison.Google Scholar
Mundt, S. Baker, R.G. (1979). A mid-Wisconsinan pollen diagram from Black Hawk County, Iowa. Proceedings, Iowa Academy of Science 86, 32–34.Google Scholar
Passega, R. (1957). Texture as a characteristic of clastic deposition. Bulletin American Association of Petroleum Geologists 41, 1952–1984.Google Scholar
Richard, R. (1970). Atlas pollinique des arbres et dequelques arbustes indigenes du Québec, I. Introduction, II. Gymnospermes. Naturaliste can. 97, 1–34.Google Scholar
Ritchie, J.C. Lichti-Federovich, S. h, 1967. Pollen dispersal phenomena in arctic-subarctic Canada. Rev. Paleobot. Palynol. 3, 255–266.CrossRefGoogle Scholar
Ritter, D.F. (1975). Stratigraphic implications of coarse-grained gravel deposited as overbank sediment, southern Illinois. Journal of Geology 83, 645–650.CrossRefGoogle Scholar
Royse, C.F. Jr.. 1970 An Introduction to Sediment Analysis Arizona State University Press, Tempe.Google Scholar
Stewart, M.T. (1976). Clay Mineralogy and Relative Age of Tills in North-Central Wisconsin. Journal of Sedimentary Petrology 46, 200–205.Google Scholar
Van Zant, K.L. Hallberg, G.R. Baker, R.G. (1980). A Farmdalian pollen diagram from east-central Iowa. Proceedings, Iowa Academy of Science 87, 52–55.Google Scholar
Washburn, A.L. (1973)Periglacial Processes and Environments St. Martins Press, New York.Google Scholar
Webb, T. III, McAndrews, J.H. (1976). Corresponding patterns of contemporary pollen and vegetation in central North America. Geological Society of America Memoir 145, 267–299.CrossRefGoogle Scholar
Whittecar, G.R. 1979a. Geomorphic history and Pleistocene stratigraphy of the Pecatonica River valley, Wisconsin and Illinois. Ph.D. dissertation University of Wisconsin-Madison.Google Scholar
Whittecar, G.R. 1979b. Late Pleistocene Geomorphic History of the Pecatonica River Valley, Wisconsin and Illinois. Abstracts with Programs North-Central section, Geological Society of America 259.Google Scholar
Whittecar, G.R. (1980). Pre-Wisconsinan Stratigraphy in a portion of the Pecatonica River Valley, Wisconsin and Illinois. Abstracts with Programs North-Central section, Geological Society of America 260.Google Scholar
Willman, W.B. Frye, L.C. (1970)Pleistocene Stratigraphy of IllinoisIllinois State Geological Survey Bulletin 94.Google Scholar
Worsley, P. (1977). Periglaciation Shotten, F.W. British Quaternary Studies: Recent Advances Clarendon Press, Oxford. 203–219.Google Scholar
Wright, H.E. Jr.. 1972. Interglacial and postglacial climates: The pollen record. Quaternary Research 2, 274–282.CrossRefGoogle Scholar
Wright, H.E. Jr.. 1981. Vegetation East of the Rocky Mountains 18,000 Years Ago. Quaternary Research 15, 113–125.CrossRefGoogle Scholar