| Abstract: | Sediment cores collected from the littoral and pelagic zones of Beaver Lake, Michigan record fluctuations in the water level of Lake Superior. Beaver Lake is a small 300 ha lake in Pictured Rocks National Lakeshore (PRNL) now separated from Lake Superior by a dune-capped barrier bar. Cores were collected using a vibracorer from a lake-ice platform in February 1997. A 2.85 m long core in 10 m of water contains well-sorted sand, rhythmites, peat, interbedded sand and gyttja, and is capped with 1 m of massive gyttja. A 9480 BP AMS age from the basal sand provides a minimum deglacial date for the area. Further analysis indicates a sand-dominated depositional environment from a low lake stand at approximately 8500 BP to present. An approximate 8800 BP red to gray sediment color transition records either the cessation of meltwater input from Lake Agassiz or receding ice, while a younger similarly colored transition, 6600 BP in age, likely records sediment reworking in the coastal zone. Four AMS ages on peat range from 8520 to 7340 BP and are indicative of the Houghton low phase. Burial of the peat by stratified sand and gyttja after 7340 BP indicates a rising lake level. Peat at a higher level in the lake basin, encountered in shallow littoral cores, ranges in age from 6800 to 6420 BP, which estimates a 0.91 m rise/century in lake level to the Nipissing level by 5000 BP. |
| Genre: | Article |
| ProdID: | 1000870 |
| Citation Author: | Fisher, Timothy G.; Whitman, Richard L. |
| Citation Contributing Office: | Great Lakes Science Center |
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| Citation End Page: | 274 |
| Citation Issue: | 2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Journal of Great Lakes Research |
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| Citation Number Of Pages: | 11 |
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| Citation Phsyical Description: | p. 263-274 |
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| Citation Public Comments: | Out-of-print |
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| Citation Search Results Text: | Deglacial and lake level fluctuation history recorded in cores, Beaver Lake, Upper Peninsula, Michigan; 1999; Article; Journal; Journal of Great Lakes Research; Fisher, Timothy G.; Whitman, Richard L. |
| Citation Start Page: | 263 |
| Citation Volume: | 25 |
| Citation Year: | 1999 |
| Type: | citation/reference |
| Text: | Deglacial and lake level fluctuation history recorded in cores, Beaver Lake, Upper Peninsula, Michigan; 1999; Article; Journal; Journal of Great Lakes Research; Fisher, Timothy G.; Whitman, Richard L. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Fri, 1 Jan 1999 00:00 -0600 |
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