Geologic Map of Michigan
Map courtesy Michigan Department of Conservation (fair use policy)
Michigan's bedrock is not very widely exposed, so you should take this bedrock map with a grain of salt. Much of the state is covered with glacial drift—ground-up Canadian rocks bulldozed onto Michigan and much of the rest of the northern United States by several Ice Age continental glaciers, like the ones that rest on Antarctica and Greenland today. Those glaciers also excavated and filled the Great Lakes that today make Michigan two peninsulas.
Beneath that blanket of sediment, the Lower Peninsula is a geologic basin that has been occupied by shallow seas for most of the last 500 million years. The central part filled in last, its shale and limestone dating from the Late Jurassic Period around 155 million years ago.
The Upper Peninsula is a cratonic upland of very ancient rocks from as long ago as Archean times, nearly 3 billion years ago. These rocks include the iron formations that have supported the American steel industry for many decades and continue to be the nation's second-largest producer of iron ore.
The 800x950 pixel version (100 KB) is fully legible and includes the key to the different colored formations. If it's not impressive enough for you, view the 2000x2400 pixel version (360 KB), which is nice and crisp and suitable for printing.
If you like the aesthetics of a traditional paper map, I've scanned the 1968 version of this map. It has the rock units denoted by time instead of name, and it also includes the surrounding geography and avoids the floating-in-space effect. That's here in a 1200x1550 pixel version (840 KB)and also the 2100x2700 pixel version (2 MB), because I can't bear to waste a good scan.
More Michigan resources on About.com:
About Detroit
Michigan Maps
Michigan Geography, State Symbols & Facts
Michigan National Parks
Michigan State Parks
Michigan Campgrounds
Michigan Scenic Roads
Michigan Archaeology
Back to Geologic Maps of the States
