| Abstract: | We propose a chronology of late Wisconsinan glacial fluctuations in middle North America, from Alberta to Wisconsin, based on radiocarbon dates derived solely from wood. Previous chronologies of the southwestern margin of the North American Continental Ice Sheet have depended to a considerable degree on radiocarbon dates from fine-grained organic sediment. This material is commonly contaminated with older carbon, resulting in chronologic confusion. By using only dates from wood, much of the confusion disappears. However, because of the scarcity of wood dates, only four of the sixteen identified fluctuations are accurately dated: an advance into Iowa about 14,000 to 13,500 BP, an advance into South Dakota and Iowa about 12,300 BP, an advance into the Lake Michigan basin about 11,700 BP, and an advance into the Lake Superior basin about 9900 BP. In addition, the beginning of late Wisconsinan glaciation, before 20,000 BP, is fairly well documented. None of the fluctuations in the western part of the region are accurately dated. ?? 1982. |
| Genre: | Article |
| ProdID: | 70011465 |
| Citation Author: | Clayton, L.; Moran, S. R. |
| Citation Contributing Office: | |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 82 |
| Citation Issue: | 1 |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Quaternary Science Reviews |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 28 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | Chronology of late wisconsinan glaciation in middle North America; 1982; Article; Journal; Quaternary Science Reviews; Clayton, L.; Moran, S. R. |
| Citation Start Page: | 55 |
| Citation Volume: | 1 |
| Citation Year: | 1982 |
| Type: | citation/reference |
| Text: | Chronology of late wisconsinan glaciation in middle North America; 1982; Article; Journal; Quaternary Science Reviews; Clayton, L.; Moran, S. R. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Fri, 1 Jan 1982 00:00 -0600 |
| Publisher: | |
