1. Education

North Dakota Geologic Map

Geologic Maps of the 50 United States

This is North Dakota without its surface blanket of glacial sand and gravel, which covers three-fourths of the state. (more below)
North Dakota's rocks

Image courtesy North Dakota Geological Survey

Click the map for a larger version
The outlines of the broad Williston basin in the west are clear; these rocks (brown and purple) all date from Tertiary times (younger than 65 million years). The rest, starting with the light blue, make up a thick Cretaceous section (140 to 65 million years) covering the eastern half of the state. A narrow strip of Archean basement, billions of years old, with a few stray blobs of much younger Ordovician (pink) and Jurassic (green) rocks, spills across the border from Minnesota.

I have prepared this map in a 1200x1000 pixel version (550 KB) that includes a key to the different rock units. You can also buy a printed 8-1/2 x 11 copy from the state; order publication MM-36.

More about North Dakota Geology

More North Dakota Resources on About.com:
North Dakota Maps
North Dakota Geography, State Symbols & Facts
North Dakota National Parks
North Dakota State Parks
North Dakota Campgrounds
North Dakota Hunting

©2013 About.com. All rights reserved.