Montana Geologic Map

Montana is an enormous state; luckily this map, produced by the Department of Earth Sciences at Montana State University from the official map of 1955, is simplified enough to be presentable on a monitor. And with the larger versions of this map you get Yellowstone National Park thrown in as a bonus, a unique area where an active hot spot is pushing fresh magma through a thick continental plate. Just to its north is the famous Stillwater Complex, a thick body of platinum-bearing plutonic rocks.

Other notable features in Montana are the glaciated country in the north, from Glacier International Park in the west to the windswept plains in the east, and the great Precambrian Belt complex in the Rockies.

The 1600x1300 pixel version (1.4 MB) includes the explanation and is fully readable. But the ultimate is the 3200x2600 pixel version (2.7 MB), with all the detail of my original scan.

Buy a paper copy of this map from Montana State University. It has more material than I've shown here. The state's Bureau of Mines and Geology published an updated state geologic map in 2007, about 1-1/2 by 2 meters in size. It costs considerably more but has infinitely more information.

More about Montana Geology

More Montana resources on About.com:
Montana Maps
Montana Geography, State Symbols & Facts
Montana National Parks
Montana State Parks for Spring
Montana State Parks for Winter
Montana Campgrounds
Montana Scenic Roads
Montana Travel
Montana Skiing
Montana Resorts & Guest Ranches
Montana Climbing
Montana Bed & Breakfasts