Mackinaw Township in Mackinaw City in Cheboygan County, Michigan — The American Midwest (Great Lakes)
Geology of the Straits
Photographed by J. J. Prats, August 2, 2024
1. Geology of the Straits Marker
Filling the basin. A salty tropical sea filled the basin. Erosion added deposits upon deposits. Coral grew and deposited their limestone shells adding abundant fossils to the bottom debris. Over the eons, the salty water evaporated and different types of debris filled the basin creating concentric bowls.
The final scouring. Cooling continued until finally snow began to fall. Glaciers gradually built to the north and oozed south scraping off the top layers of rock. After several advances and retreats, the rims of the bowls of debris were exposed. The softest rock, of the Devonian era, was scoured out leaving the basins of Lake Michigan and Huron that filled with water.
Today we benefit from the deposits.
The bottom sand has been converted to the red sandstone used in the construction of beautiful buildings in Manquette
Salt and gypsum deposits are mined from the evaporation of the salty sea
Limestone is mined around the Straits
this page online
Erected 2021.
Topics. This historical marker is listed in this topic list: Environment.
Location. 45° 47.022′ N, 84° 43.387′ W. Marker is in Mackinaw City, Michigan, in Cheboygan County. It is in Mackinaw Township. It is on North Huron Avenue north of East Etherington Street, on the right when traveling north. It is in Wawatam Park. Touch for map. Marker is at or near this postal address: 300 N Huron Ave, Mackinaw City MI 49701, United States of America. Touch for directions.
Regionally, this marker is in Northern Michigan Lower Peninsula, on the Straits of Mackinac, and in one of the Lake Huron Shore counties. It is also in the American Midwest and on the Great Lakes. Globally, it is in North America, the Great North Woods, the Western Hemisphere, the Western World, and the Anglosphere. Historically, it finds itself in what was once the Northwest Territory.
Other nearby markers. At least 8 other markers are within walking distance of this marker: Where are the Clouds? The Snow? (here, next to this marker); A Bridge for Mackinac (here, next to this marker); John L. (Jack) Staffan Chief Wawatam (a few steps from this marker); Lake Level Research (a few steps from this marker); Mackinaw Boat - Mackinaw Coat (within shouting distance of this marker); Chief Wawatam (within shouting distance of this marker); a different marker also named Chief Wawatam (within shouting distance of this marker); Historic Timeline (within shouting distance of this marker). Touch for a list and map of all markers in Mackinaw City.
Other markers no longer nearby. Island-Hopping the Straits (was here, next to this marker but has been replaced with another marker now near
Photographed by J. J. Prats, August 2, 2024
2. Geology of the Straits Marker
More about this marker. This interpretive panel is illustrated with two maps and two photographs. Clockwise from the left:
Michigan Basin (3 miles deep) within the Canadian Shield
(a photograph of coral)
Rims of the bowls of sediments filling the Michigan Basin are exposed in concentric circles around the state
Massive equipment is used at a huge mine in Rogers City to excavate limestone.
Credits. This page was last revised on August 23, 2024. It was originally submitted on August 23, 2024, by J. J. Prats of Powell, Ohio. This page has been viewed 169 times since then and 18 times this year. Photos: 1, 2. submitted on August 23, 2024, by J. J. Prats of Powell, Ohio.
