Date of this Version
Voorhies, M.R., Goodwin, R.G., Courtesy of HWS Technologies Inc. 1989. Plio-Pleistocene Glacial Deposits in Northeastern Nebraska: New Exposures and Interpretations. Univerity of Nebraka; Nebraska Geological Society.
A field trip sponsored by the Nebraska Geological Society. Trip Leaders: Dr. M.R. Voorhies, University of Nebraska State Museum. & Dr. R.G. Goodwin, HWS Technologies Inc. Spring 1989
Recent interpretation of oxygen isotopic data for benthic and planktonic foraminifera recovered during ocean drilling programs suggest that world ice volume was greater than the ice volume of 18 thousand years ago (Late Wisconsinan) approximately 2.5 million years ago (Prentice and Matthews, Geology, November, 1988). This agrees well With biostratigraphic and paleoecologic interepretations drawn from sediment cores obtained from the Arctic Ocean Basin. The latter data suggest complete ice cover of the basin during the period 2.2-2.4 million years ago (Scott et at., G.S.A. Bulletin, February, 1989). John Boollstorff inferred that one or more glacial tills of the North American mid-continent were deposited at this time. BoeUstorff drew his conclusions primarily from subsurface samples and from volcanic ash horizons dated by the fisssion-track method. The purpose of this trip is to examine fossil-bearing outcrops of sand and gravel or silt that are associated With volcanic ash or glacial till and that provide information about the timing of glacier advance into northeastern Nebraska. The trip Will begin at the Knox County Court House, Center, Nebraska at noon on saturday May 6, 1989. Participants are responsible for providing their own transportation.