Abstract
Publisher Summary This chapter discusses the glacial history of Michigan, U.S.A. At its maximum, the Laurentide Ice Sheet in the Great Lakes region, comprised the Green Bay, Lake Michigan, Saginaw and Erie lobes, extended south of Michigan into central Ohio, Northwestern Indiana, and North-Eastern Illinois. The Saginaw lobe, the thinnest of the four lobes, melted the fastest uncovering south-central Lower Michigan first. During the next 5500 years, continued recession was interrupted by minor ice margin readvances in the ice sheet that formed a series of end moraines across central Lower Michigan. While retreating, a series of proglacial lakes formed at the margin of the Laurentide Ice Sheet at sites where the land sloped towards the ice front. The earliest proglacial lakes to form in Lower Michigan were glacial Lake Chicago and Lake Maumee within the Lake Michigan and Erie basins. The lake level stabilised long enough to form three successively lower beach ridges. The chapter discusses that after the Lake Michigan and Saginaw lobes had melted Northward into Northern Lower Michigan, the Laurentide Ice Sheet surged back into Lake Michigan, Huron and Erie basins. This surge, called the Port Huron advance, resulted in the formation of glacial Lake Saginaw and Lake Whittlesey in the Lake Huron and Erie lake basins, respectively. The Port Huron end moraine, which marks this significant readvance, is a very prominent topographic feature throughout much of Michigan. Continued melting after the Port Huron advance, once again exposed the thumb of Michigan, leading to the formation of glacial Lake Warren around 12,800 B.P.
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