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The Mosbeck Site: a Paleoenvironmental Interpretation of the Late Quaternary History of Lake Agassiz Based on Fossil Insect and Mollusk Remains

Published online by Cambridge University Press:  20 January 2017

Allan C. Ashworth ,
Lee Clayton  and
William B. Bickley
Allan C. Ashworth
Affiliation:
Department of Geology, North Dakota State University, Fargo, North Dakota, 58102 USA
Lee Clayton
Affiliation:
Department of Geology, University of North Dakota, Grand Forks, North Dakota, 58201 USA
William B. Bickley
Affiliation:
Department of Geology, University of North Dakota, Grand Forks, North Dakota, 58201 USA
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Abstract

The Mosbeck Site is in the southern part of the Lake Agassiz basin in northwestern Minnesota. The stratigraphic section at the site consists of seven lithologic units, which are from bottom to top (A) unsorted, pebbly, sandy, silty clay, (B) coarse gravel, (C) silty sand, (D) peat, (E) fine sand, (F) interbedded sand and gravel, and (G) unbedded dirty gravel. The lower few centimeters of unit E are unoxidized and contain black spruce and tamarack driftwood, which has been radiocarbon dated at 9940 ± 160 BP (I-3880). Units C-E contain numerous, well-preserved insect and mollusk remains. These fossils have been compared with modern species, and at least 76 insect and 15 mollusk taxa are present. Assuming that their ecological tolerances have changed little in the past 10,000 years, they provide valuable information about the environment of Lake Agassiz. Few of the insects are now found in the region, indicating that the environment has changed. With few exceptions the species present indicate that the climate and vegetation at the time were similar to the present-day climate and vegetation of southeastern Manitoba.

The lithology and faunal contents of the sediment are interpreted as follows. Unit A is Late Wisconsinan glacial sediment. Unit B is a lag concentrate formed by wave action during a regressive phase of Lake Agassiz. Unit C is the sediment of a small body of water that formed when the level of Lake Agassiz had dropped below the site. The banks were covered with a spruce forest. Open water gave way to swampy conditions, and unit D was formed. Both units C and D were deposited during the low-water Moorhead Phase of Lake Agassiz. Units E and F are shoreline sediment deposited as the lake level rose, drowning the vegetation. Unit G is modern ditch spoil.

Type
Original Articles
Information
Quaternary Research , Volume 2 , Issue 2 , September 1972 , pp. 176 - 188
Copyright
Academic Press, Inc.

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References

Ashworth, A.C. Brophy, J.A. 1972 A Late Quaternary Fossil Beetle Assemblage from the Missouri Coteau, North DakotaGeological Society of America Bulletin. In pressGoogle Scholar
Brophy, J.A. 1967 Some Aspects of the Geological Deposits of the South End of the Lake Agassiz Basin Mayer-Oakes, W.J. Life, Land and Water University of Manitoba Press Winnipeg 97–105 Google Scholar
Campbell, J.M. 1968 New World Micropeplinae The Canadian Entomologist 100 225–267 Google Scholar
Coope, G.R. 1967 The Value of Quaternary Insect Faunas in the Interpretation of Ancient Ecology Cushing, E.J. Wright, H.E. Jr. Quaternary Paleoecology Yale University Press New Haven, Connecticut 359–380 Google Scholar
Coope, G.R. Osborne, P.J. 1967 Report on the Coleopterous Fauna of the Roman Well at Barnsley Park, Gloucestershire Transaction of the Bristol and Gloucestershire Archaeological Society 86 84–87 Google Scholar
Darlington, P.J. 1938 The American Patrobini (Coleoptera, Carabidae) Entomologica Americana 18 135–182 Google Scholar
Elson, J.A. 1967 The Geology of Glacial Lake Agassiz Mayer-Oakes, W.J. Life, Land and Water University of Manitoba Press Winnipeg 37–105 Google Scholar
Harris, K.L. Moran, S.R. Clayton, Lee, 1972 Stratigraphic Subdivision of the Coleharbor Formation (Quaternary) in the Grand Forks Area, North Dakota and Minnesota North Dakota Geological Survey Miscellaneous SeriesIn pressGoogle Scholar
Hibbard, C.W. Taylor, D.W. 1960 Two Late Pleistocene Faunas from Southwestern Kansas Michigan University Museum of Paleontology Contribution 16 No. 1 1–223 Google Scholar
Lindroth, C.H. 1961 The Ground Beetles of Canada and Alaska Opuscula Entomologica Supplementum 10 1–200 Google Scholar
Lindroth, C.H. 1963 The Ground Beetles of Canada and Alaska Opuscula Entomologica Supplementum 14 201–408 Google Scholar
Lindroth, C.H. 1966 The Ground Beetles of Canada and Alaska Opuscula Entomologica Supplementum 19 409–648 Google Scholar
Marx, E.J.F. 1957 A Review of the Subgenus Donacia in the Western Hemisphere (Col. Donaciidae) Bulletin of the American Museum of Natural History 112 Google Scholar
Moran, S.R. Clayton, Lee, Cvancara, A.M. 1971 New Sedimentological and Paleontological Evidence for History of Lake Agassiz: Snake Curve Section, Red Lake County, Minnesota Proceedings of the North Dakota Academy of Sciences 24 61–73 Google Scholar
Prest, V.K. 1969 Retreat of Wisconsin and Recent ice in North America Canada Geological Survey Map 1257A Google Scholar
Shay, C.T. 1967 Vegetation History of the Southern Lake Agassiz Basin during the past 12,000 years Mayer-Oakes, W.J. Life, Land and Water University of Manitoba Press Winnipeg 231–252 Google Scholar
Tuthill, S.J. 1963 Molluscan Fossils from Upper Glacial Lake Agassiz Sediments in Red Lake County, Minnesota North Dakota Scientific Proceedings 17 96–101 Google Scholar
Tuthill, S.J. Laird, W.M. Kresl, R.J. 1964 Fossiliferous Marl beneath Lower Campbell (Glacial Lake Agassiz) Beach Sediments North Dakota Scientific Proceedings 18 135–140 Google Scholar