Abstract

The late-glacial stratigraphy of the northern part of the Kennebec River valley of Maine indicates the following sequence of events. (1) As the last extensive ice sheet dissipated in Maine, the sea inundated parts of the deglaciated and isostatically depressed region and deposited the Presumpscot Formation. (2) During emergence, outwash of the Embden Formation was gradationally deposited on the Presumpscot Formation. (3) As emergence progressed, the Embden and Presumpscot Formations were deeply incised by the early Kennebec River. (4) Outwash (?) of the North Anson Formation was later deposited within this incision.

The geologic sequence of events, radiocarbon dates in the area, and correlation of events of the Maine, Quebec, New Brunswick, and Nova Scotia region suggest that the last extensive ice sheet to cover the region dissipated more rapidly in eastern Maine and New Brunswick than in the highlands of New Hampshire and western Maine. The data also suggest that ice persisted in the highlands during the time of the Cary-Port Huron Interstade, perhaps dissipating during the time of the Port Huron- Valders Interstade of the mid-continental sequence. These highlands probably later became a center for ice accumulation and radial outflow. This ice cap probably grew synchronously with the main Valders ice sheet to the north, with cirque glaciers on Mount Katahdin, Maine, and with the ice cap in southwestern Nova Scotia.

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