Fossil wood recovered in gravel at a depth of 129 ft (40 m) from a west-central Indiana water-well drilling was dated at 30,070 ± 240 14C y BP. This date represents a time period in Indiana between ∼23,000–40,000 y BP from which no known previous radiocarbon dates have been recorded. Fragments of wood were determined to be mostly Picea, and at least one fragment is referable to Larix. The macrofossils indicate the presence of boreal conditions in west-central Indiana at the beginning of the Plum Point Interstadial. Analysis of the gravel associated with the wood macrofossils suggests that the organic material was incorporated into the ice of the Lake Michigan lobe of the Laurentide Ice Sheet late in the Altonian Substage of the Late-Wisconsinan between 21,000 y BP and 26,000 y BP.
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1 April 2008
Middle-Wisconsinan Gravel and Wood from a Well-drilling in West-central Indiana
ANTHONY L. SWINEHART,
Jacob Napieralski,
Nicole M. Geist
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The American Midland Naturalist
Vol. 159 • No. 2
April 2008
Vol. 159 • No. 2
April 2008