GEOLOGIC MAPPING

Gasconade Dolomite near Van Buren, Missouri

Outcrop of Gasconade Dolomite near Van Buren, Missouri

The bedrock geology in the area between Hurricane Creek and the Current River was mapped from 1995 to 2001 as part of a USGS National Cooperative Geologic Mapping Program. The traditional mapping of bedrock formations was augmented by a concentrated effort to identify fractures (a break in the bedrock caused by stress relief, including cracks, joints, and faults), bedding planes (a rock layer surface that tends to split, break, or separate from overlying or underlying layers), and other rock features that can affect ground-water flow. The physical characteristics of each observed fracture and bedding plane were described onsite. These characteristics include length, width, and orientation of the rock opening, and evidence that the fracture or bedding-plane openings were being decreased (cementation) or enlarged (dissolution) by ground-water flow (McDowell, 2000; McDowell and others, 2000). Most of the cave systems in this area have developed along bedding planes, indicating that ground water formerly flowed preferentially along bedding planes(Orndorff and others, 2001).

For more information contact:

Michael J. Kleeschulte, Hydrologist

U.S. Geological Survey

Missouri Water Science Center

1400 Independence Rd., MS 100

Rolla, MO 65401

Telephone: (573) 308-3675

Fax:(573) 308-3645