¹Geological Survey of Canada, Natural Resources Canada, Bedford Institute of Oceanography, Box 1006, Dartmouth NS B2Y 4A2, Canada
²Department of Earth Sciences, University of Waterloo, 200 University Avenue, Waterloo ON N2L 3G1, Canada
³Department of Earth Sciences, Brock University, 500 Glenridge Avenue, St. Catharines ON L2S 3A1,Canada
⁴Graduate School of Oceanography, University of Rhode Island, South Ferry Road, Narragansett RI 02882-1197, U.S.A
⁵Department of Geological Sciences, University of Michigan, C.C. Little Building, 1000 North University Street, Ann Arbor MI 48109-1005, U.S.A.

*Corresponding author: miklewis@nrcan.gc.ca

Abstract

   Water bodies, ancestral to the present lakes including Lake Huron, first appeared in the southern Great Lakes basin about 15,500 ¹⁴C years (18,800 cal years) BP during the oscillatory northward retreat of the last (Laurentide) ice sheet from its maximum position south of the Great Lakes watershed. Glacial lakes, impounded by a retreating ice margin on their northern shores, were continuously present after 13,000 ¹⁴C (15,340 cal) BP for 3000 ¹⁴C (3900 cal) years. Drainage routings varied in time through the Erie and Michigan basins to the Mississippi River system, a probable source for colonizing aquatic organisms, then to the Ontario basin, and finally northeastward to the Ottawa River valley via the isostatically-depressed North Bay outlet by 10,000 ¹⁴C (11,470 cal) BP. Water levels were generally low between 10,000 and 7500 ¹⁴C (11,470 and 8300 cal) BP and may have risen several tens of metres for short periods due to overflow of meltwater from upstream subglacial reservoirs or from glacial lakes impounded by residual ice in the Hudson Bay watershed.
About 8000 ¹⁴C (8890 cal) BP glacial runoff bypassed the Great Lakes, and Huron basin waters descended into hydrologic closure under the influence of the early Holocene dry climate. With increasing precipitation and water supply about 7500 ¹⁴C (8300 cal) BP the Huron water body again overflowed its North Bay outlet. Differential isostatic uplift (fastest to the north-northeast) raised this outlet and lake level relative to the rest of the basin. The lake finally overflowed southern outlets at Chicago and Port Huron-Sarnia by 5000 ¹⁴C (5760 cal) BP (during the Nipissing highstand). Enhanced erosion of the latter outlet and continued differential uplift of the basin led to the present configuration of Lake Huron and Georgian Bay.