Abstract

Geological interpretation and radio carbon dating of an excellent exposure in a wave-cut cliff on the shore of Lake Michigan near South Haven, Michigan, permits the establishment of the following absolute chronology of events for the Lake Michigan Basin: Two Creeks-Bowmanville low-water stage, 11,000 years ago; end of Lake Algonquin, 8000 years ago; Lake Chippewa low-water stage, 5000 years ago; and beginning of the Nipissing Great Lakes, a little less than 4000 years ago.

Pollen profiles from the South Haven section and from a bog near Hartford, Michigan, on the Valparaiso ground moraine reveal the following forest succession in southwestern Michigan from Two Creeks time to the present: spruce-fir to Jack pine to white-red pine to oak to oak-hemlock-broad-leaved forest to oak-pine. Radiocarbon dating indicates that the close of the spruce-fir period was 8000 years ago; the Jack pine period, 7000 years ago; the white-red pine period, 6000 years ago; the oak-pine period, 5000 years ago; and the oak-hemlock-broad-leaved forest (Xerothermic), 4000 to 3500 years ago.

The difference in time between Lake Algonquin and the Nipissing Great Lakes was 4000 years. The Xerothermic is correlated with the Nipissing Great Lakes at 4000–3500 years ago.

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