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Geohydrology of bedrock aquifers in the Northern Great Plains in parts of Montana, North Dakota, South Dakota, and Wyoming

Professional Paper 1402-E

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Abstract

Rocks of Paleozoic and Mesozoic age underlie the entire northern Great Plains of the United States. These rocks form 5 artesian aquifer systems that are recharged in the mountainous areas of Montana, South Dakota, and Wyoming and extend more than 600 miles to discharge areas in the northeastern part of North Dakota and in the Canadian Province of Manitoba. Generally, the principal direction of flow in each aquifer is deflected to the north and south around the Williston basin. Flow through the Williston basin is restricted because of geologic structure, and decreased permeability of rocks in the deeper parts of the basin. Major fracture systems or lineaments traverse the geologic section and are either vertical or horizontal conduits, or barriers to, groundwater flow. Vertical leakage from the aquifers is restricted by shale of minimal permeability, halite beds, and stratigraphic traps or minimal-permeability zones associated with petroleum accumulations. Interaquifer leakage appears to occur through and along some of the major lineaments. During the Pleistocene Epoch, thick ice sheets completely covered the discharge areas of the bedrock aquifers. This effectively blocked flow northeastward from the system and, at some locations, it may have caused a reversal of flow. The existing flow, system therefore, may not have reached hydrologic equilibrium with the stress of the last glacial period. (USGS)

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Geohydrology of bedrock aquifers in the Northern Great Plains in parts of Montana, North Dakota, South Dakota, and Wyoming
Series title:
Professional Paper
Series number:
1402
Chapter:
E
Edition:
-
Year Published:
1986
Language:
ENGLISH
Description:
p. E1-E87; 3 plates in pocket