Mickelson, D.M., 2001, Late-glacial and post-glacial drainage connections to the Upper Great Lakes: possible routes of fish migration?: International Association for Great Lakes Research, 44th Conference on Great lakes Research, Program and Abstracts, p. (01-2)

By about 23,000 BP all of the present upper Great Lakes drainage basin was filled with glacier ice to depths of 100s of meters, eliminating the possibility of fish survival in the basin. Ice advances as late as about 14,000 years filled the basin, but soon after ice had retreated into the southern part of the Lake Michigan basin. Drainage from Lake Erie entered early Lake Michigan via Saginaw Bay and the Grand River. Drainage out of the lake was into the Illinois River. At this time the iceberg choked lake bordered a calving glacier margin. By about 13,000 BP the ice margin had retreated north to the Straits, and Huron and Michigan were connected. At about this time Lake Superior opened and drainage carried a large volume of red-brown silt and clay into the Michigan-Huron basin. From this time on deep lake conditions have existed in the south ends of the Lake Michigan and Huron basins, but ice periodically occupied the northern parts of the basins until about 11,000 BP. Large influxes of water from the Lake Agassiz basin to the west entered Lake Superior and coursed through Michigan and Huron as well as down the Mississippi.