Geology and Geography
Many eons ago, a combination of cataclysmic volcanic eruptions and soupy tropical seas initially formed what we know now as Michigan. In the northern part of the state, around Lake Superior and northern Lake Huron, erupting volcanoes laid down thick layers of basalt, which later tilted and faulted, forming the area’s rugged, rocky topography of mountain ranges and steep shorelines.
Farther south, a shallow sea covered the vast Michigan Basin, an area that now encompasses the lower four Great Lakes. Over millions of years, sand, shells, and other detritus compacted into thick layers of sedimentary rock, the limestone, dolomite, sandstone, and shale now found from the shores of northern Lake Michigan to the state’s southern border.
Much later, powerful glaciers added their indelible touch to the Michigan landscape, the last one as recently as 12,000 years ago. Four separate ice sheets scraped across the region, scouring out depressions that became lakes, lowlands, and ragged shorelines. When the ice melted and glaciers retreated, the water filled vast basins and created the modern-day Great Lakes.
Michigan comprises three distinct land regions: the Superior Uplands, Northern Highlands, and Great Lakes Plains. The Superior Uplands spans the western two-thirds of the Upper Peninsula, the region formed by ancient volcanic activity. It is a landscape of dramatic beauty, characterized by rugged basalt cliffs and thick boreal forests of fir, spruce, and birch—all part of the vast Canadian Shield that dips down from the Arctic, across portions of the northern Great Lakes region, and up the west side of Hudson Bay in a giant horseshoe. Much of the region rises more than 1,000 feet above sea level, including the state’s highest point, Mt. Arvon, which tops out at 1,979 feet. The Superior Uplands harbors some of the nation’s richest sources of minerals, especially copper and iron ore deposits.
South of the Superior Uplands lies the Northern Highlands, covering the eastern Upper Peninsula and the northern Lower Peninsula. Here, basalt bedrock gives way to sandstone and limestone, and boreal forests segue into pine and hardwoods. Once heavily logged for its vast, valuable stands of white and red pine, the Northern Highlands area is now prized by recreationists for its woods, water, and wildlife.
The Great Lakes Plains stretches across southern Michigan (as well as southern Wisconsin and northern Ohio). This region received the full brunt of the Ice Age and its powerful glaciers, which left behind a flattened landscape of sandy lakebeds, wetlands, prairies, and fertile topsoil, making it Michigan’s primary farming region for a variety of fruit and vegetable crops.
Geographically, no other state is so distinctly divided. Michigan consists of two separate landmasses, the Lower Peninsula and the Upper Peninsula, circled by Lakes Michigan, Superior, Huron, and Erie, and connected by the Mackinac Bridge, which spans five miles across the Straits of Mackinac.
Ask Michiganders to give you directions in the Lower Peninsula, and odds are they’ll hold up a right hand and use their palm to pinpoint within the state. Shaped like a mitten, the Lower Peninsula is 286 miles long and 195 miles wide, with the landmass jutting out into Lake Huron universally dubbed “the Thumb.”
The Upper Peninsula shares a border with northeastern Wisconsin, then stretches east for 334 miles between Lakes Superior and Michigan, and reaches a third Great Lake, Huron, where it terminates at Drummond Island. Also considered part of the U.P. is 45-mile-long Isle Royale, the largest island in Lake Superior. The entire Isle Royale archipelago is a national park, one of the most remote and least-visited in the national park system.
Altogether, Michigan’s landmass covers 58,110 square miles, making it the largest state east of the Mississippi. But it is water that defines Michigan, and helps to make it the 10th largest state in America. Along with its 3,288-mile shoreline—second only to Alaska—it encompasses more than 11,000 lakes, over 36,000 miles of rivers, and nearly 200 waterfalls, and boasts 16 federally designated Wild and Scenic Rivers. Both the Upper and Lower Peninsulas are home to a national lakeshore—Pictured Rocks and Sleeping Bear Dunes, respectively.
The Great Lakes State, Water Wonderland, Land of Hiawatha… many of Michigan’s nicknames accurately describe this most beautiful of Midwestern states.
by Laura Martone from Moon Michigan, 3rd Edition, © Avalon Travel