| Abstract: | Organic material exposed within a small swale fill in Pit 6 of the Wedron Silica Sand Co. near Wedron in LaSalle County, Illinois, includes well-preserved pollen, plant macrofossils, and insect remains. This material occurs in slackwater sediment in the lower part of the Peddicord Formation, which was deposited as existing valleys were dammed by fluvial aggradation during the initial late Wisconsinan advance of Laurentide ice into the Wedron area. Wood from the organic horizon has a radiocarbon age of 21,460 ?? 470 yr B.P. (ISGS-1486). The pollen spectrum is dominated by Picea, Pinus, and Cyperaceae. Plant macrofossils comprise a mix of boreal-forest taxa, including Picea, Larix laricina, and the moss Campylium stellatum; subarctic species including Betula glandulosa, Empetrum nigrum, and Selaginella selaginoides; along with the predominantly arctic Vaccinium uliginosum var. alpinum, Dryas integrifolia, and Rhododendron lapponicum. The insect fauna contains the western montane ground beetle Opisthius richardsoni; several arctic-subarctic ground beetles including Diacheila polita, Helophorus sibiricus, and Pterostichus (Cryobius) caribou; and a diverse assemblage of insects that today inhabit the boreal forest. We interpret the biotic record to record a phase in the transition from closed boreal forest to open tundra as climatic conditions deteriorated in advance of continental glaciation. ?? 1990. |
| Genre: | Article |
| ProdID: | 70016284 |
| Citation Author: | Garry, C. E.; Schwert, D. P.; Baker, R. G.; Kemmis, T. J.; Horton, D. G.; Sullivan, A. E. |
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| Citation End Page: | 399 |
| Citation Issue: | 3 |
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| Citation Language: | English |
| Citation Larger Work Title: | Quaternary Research |
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| Citation Number Of Pages: | 13 |
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| Citation Publisher: | Elsevier |
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| Citation Search Results Text: | Plant and insect remains from the Wisconsinan interstadial/stadial transition at Wedron, north-central Illinois; 1990; Article; Journal; Quaternary Research; Garry, C. E.; Schwert, D. P.; Baker, R. G.; Kemmis, T. J.; Horton, D. G.; Sullivan, A. E. |
| Citation Start Page: | 387 |
| Citation Volume: | 33 |
| Citation Year: | 1990 |
| Type: | citation/reference |
| Text: | Plant and insect remains from the Wisconsinan interstadial/stadial transition at Wedron, north-central Illinois; 1990; Article; Journal; Quaternary Research; Garry, C. E.; Schwert, D. P.; Baker, R. G.; Kemmis, T. J.; Horton, D. G.; Sullivan, A. E. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1016/0033-5894(90)90064-R |
| Date Other: | Mon, 1 Jan 1990 00:00 -0600 |
| Publisher: | Elsevier |
