Late Stage 5 Glacio-isostatic Sea in the St. Lawrence Valley, Canada and United States
Although post-glacial marine sediments of late Wisconsinan and early Holocene age are common in eastern Canada and the northeastern United States, remnants of older Pleistocene marine sediments are scarce. A fossiliferous marine clay that predates the classical Wisconsinan was recently discovered in the St. Lawrence Valley. A dominantly estuarine environment is inferred from the geochemistry of the shells (??18O = -7.1) and from benthic foraminifer and ostracode assemblages. The clay indicates a marine invasion (Cartier Sea) shallower and probably shorter than that during the upper late Wisconsinan Champlain Sea episode (12,000-9,500 yr B.P.). The pollen content shows that regional vegetation during the marine episode began as open tundra, then became a Betula and Alnus crispa forest, reached a climatic optimum with Quercus, Corylus, and Abies, and concluded as a Pinus/Picea boreal forest. A corrected infrared stimulated luminescence age of 98,000 ?? 9000 yr is compatible with the epimerization ratio of shells. The Cartier Sea resulted from a post-glacial glacio-isostatic marine invasion in the St. Lawrence lowlands. It probably occurred during late stage 5 and is tentatively assigned to the transition of oxygen isotope substages 5b/5a. This marine episode dates to stage 5 of the preceding continental glacier which extended to middle latitudes in NE America. ?? 1996 University of Washington.
Citation Information
Publication Year | 1996 |
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Title | Late Stage 5 Glacio-isostatic Sea in the St. Lawrence Valley, Canada and United States |
DOI | 10.1006/qres.1996.0015 |
Authors | S. Occhietti, S. Balescu, M. Lamothe, M. Clet, T. Cronin, P. Ferland, P. Pichet |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Quaternary Research |
Index ID | 70018492 |
Record Source | USGS Publications Warehouse |