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Maps

Our programs produce accurate geologic maps and 3-D geologic frameworks that provide critical data for sustaining and improving the quality of life and economic vitality of the Nation. They also organize, maintain, and publish the geospatial baseline of the Nation's topography, natural landscape, built environment and more.

Geologic Maps

Geologic Maps

Map Releases

Map Releases

Topo Maps

Topo Maps

Volcanic Maps

Volcanic Maps

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Bedrock topography of northeast Iowa Bedrock topography of northeast Iowa

The bedrock in Iowa (Hershey, 1969) is generally overlain by deposits of glacial drift and alluvium, which range in thickness from less than 1 foot (0.3 m) to more than 400 ft (18 m), respectively. The configuration of the bedrock surface is the result of a complex system of ancient drainage courses when were developed during a long period of preglacial erosion and during shorter, but...
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