Cary–Port Huron Interstade: Evidence from a Buried Bryophyte Bed, Cheboygan County, Michigan
William R. Farrand, Robert Zahner, William S. Benninghoff, 1969. "Cary–Port Huron Interstade: Evidence from a Buried Bryophyte Bed, Cheboygan County, Michigan", United States Contributions to Quaternary Research; Papers Prepared on the Occasion of the VIII Congress of the International Association for Quaternary Research Paris, France, 1969, Stanley A. Schumm, William C. Bradley
Download citation file:
Radiocarbon dating of a thin layer of mosses sandwiched between two thick layers of reddish-brown sandy clay till yielded an age of 12,500 to 13,000 years B.P. These dates and a pollen spectrum that suggests a locally treeless flora form the basis for correlation with the Cary–Port Huron interstade of the Wisconsin glaciation. The absence of a Two Creeks horizon at this site and the presence of a single unit of till showing no evidence of an erosional break between Cary–Port Huron time and Glacial Lake Algonquin time is interpreted as evidence that the Straits of Mackinac was not deglaciated during Two Creeks time. It would have been the Petoskey-Cheboygan lowland, according to this interpretation, that drained the low-level Two Creeks lake from Lake Michigan to Lake Huron. Furthermore, in northern Cheboygan County red clayey till, formerly considered to be unique in this area to the Valders Stade, was deposited also by Port Huron and pre–Port Huron ice.