If we could scrape away the Paleozoic, Mesozoic and Cenozoic deposits from the Continents, we would find that the ancient, Precambrian basement rock has a topography of ridges, valleys, plains and basins, similar to what we find on our planet's surface today. One of the basins, centered on the lower peninsula of Michigan, stretches from western New York to eastern Wisconsin and from Ontario, Canada to northern Ohio and Indiana.
Known as the Michigan Basin, this broad bowl has gradually filled with sedimentary rocks from the Paleozoic and Mesozoic Eras; as one might expect, sediments advance in age from top to bottom and, on the surface, from the center of the basin to the periphery. The youngest of these deposits, Jurassic in age, are found in the west-central region of lower Michigan while the oldest surface in Ontario (on the north edge of Lake Huron), across the Upper Peninsula of Michigan, along the eastern side of Wisconsin, in Greater Chicago and in the vicinity of Niagara Falls. Most of the basin sediments have since been covered by a thick layer of Pleistocene glacial till and, of course, by the waters of Lakes Superior, Michigan, Huron and Erie.
Over the next two weeks, my wife and I plan to circle across the Michigan Basin, spending two days on Mackinac Island and most of our time along the Upper Peninsula of Michigan. Since I have been through that region in the past, I generally know what to expect but, like all journeys, the adventure lies in the unexpected. Reports from the Basin will follow.
