Madison Group, Williston Basin (07)

Comments on Geologic Parameters

07 Top Seal Thickness:

The Big Snowy Group and the Charles are the top seal for the Madison Group. The top-seal map (Peterson, 1981, in Downey, 1986) shows maximum thickness for the Big Snowy Group of about 1,000 ft.

07 Map:

07 Reference:

Downey, J. S., 1986, Geohydrology of bedrock aquifers in the northern Great Plains in parts of Montana, North Dakota, South Dakota and Wyoming: U.S. Geological Survey Professional Paper 1402-E, 87 p.

Downey, J. S., 1984, Geohydrology of the Madison and associated aquifers in parts of Montana, North Dakota, South Dakota and Wyoming: U.S. Geological Survey Professional Paper 1273-G, 47 p.