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Pollen analysis of pond deposits in the upper reaches of a stream from northeastern Iowa, an area beyond the last glacial margin, provides a nearly complete record of vegetational changes during the last 12.5 thousand years. Sixty-one radiocarbon dates provide good chronological control. Spruce forest was replaced by deciduous forest before 9.1 thousand(More)
A sequence of paleosols in the Solo Basin, Central Java, Indonesia, documents the local and regional environments present when Homo erectus spread through Southeast Asia during the early Pleistocene. The earliest human immigrants encountered a low-relief lake-margin landscape dominated by moist grasslands with open woodlands in the driest landscape(More)
Sangiran (Solo Basin, Central Java, Indonesia) is the singular Homo erectus fossil locale for Early Pleistocene Southeast Asia. Sangiran is the source for more than 80 specimens in deposits with (40)Ar/(39)Ar ages of 1.51-0.9 Ma. In April 2001, we recovered a H. erectus left maxilla fragment (preserving P(3)- M(2)) from the Sangiran site of Bapang. The find(More)
In this paper, we argue that there is tremendous potential for nitrate-N reductions to occur throughout the Corn Belt region of the USA if we simply let naturally occurring wet spots on the landscape be wet. Geologic and hydrologic data gathered in the Walnut Creek watershed located in south-central Iowa provides compelling evidence that substantial(More)
would also like to extend thanks to the many land owners (e.g. Starr family) for their cooperation and logistical support during the completion of this project. I would like to extend my sincere thanks and gratitude to my thesis advisor, Dr. Robert L. Brenner for his help with the completion of this thesis. Dr. Brenner has been an excellent teacher both in(More)
Sediments along 1st–5th-order streams in Midwestern USA contain excellent records of abrupt climatic change in the Holocene. Cutbank exposures provide AsnapshotsB of areal paleovegetation based on assemblages of well-preserved pollen and plant macrofossils; when these sites are radiocarbon dated and arranged chronologically, a detailed picture of Holocene(More)
Naturally-occurring radioactive materials (NORM) associated with unconventional drilling produced fluids from the Marcellus Shale have raised environmental concerns. However, few investigations into the fundamental chemistry of NORM in Marcellus Shale produced fluids have been performed. Thus, we performed radiochemical experiments with Marcellus Shale(More)
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