Age:

Mississippian

Type designation:

Type section: The Kenwood Sandstone was named by Butts (1915, p. 148) for exposures on Kenwood Hill in the southern part of Louisville, Kentucky, and was defined by him as lying between the New Providence Shale below and the Rosewood Shale above (Nancy Member of the Borden Formation of present Kentucky use) (Rexroad, 1986).

History of usage:

Extension of name: Stockdale (1931, p. 94) identified the Kenwood in Indiana and considered it as either a member or a bed of the New Providence Shale (Rexroad, 1986).

Change in name: Recent use in Indiana has been as the Kenwood Siltstone Member of the New Providence Shale (Kammer, Ausich, and Lane, 1983), but shale is the dominant lithology (Rexroad, 1986). Because the lithology includes siltstone as well as, shale, the unit in Indiana is called the Kenwood Member of the New Providence Shale (Rexroad and Lane, 1984; Rexroad, 1986).

Description:

The Kenwood is generally less than 40 ft (12 m) thick, but its maximum thickness is 110 ft (34 m) (Rexroad, 1986). The shale in the Kenwood is like that of the rest of the New Providence and is dark greenish to bluish gray and weathers to a lighter color (Kepferle, 1977; Rexroad, 1986). The siltstone is gray to dark gray and weathers to light gray with limonitic stains (Rexroad, 1986). It is generally in well-indurated, more or less planar beds ranging from 0.1 to 20 ft (0.03 to 6 m) in thickness (Rexroad, 1986). In places, the siltstone fills channels, and there is evidence that in places, it was deposited as a turbidite (Rexroad, 1986). Maximum siltstone content of the member is to the east (Kepferle, 1977; Rexroad, 1986).

Distribution: The Kenwood is an irregular elongate body about 50 miles (80 km) long that thins and pinches out westward. Its northern limit is in Floyd County (Rexroad, 1986). It drops stratigraphically to the west, so that a tongue of the undifferentiated New Providence intervenes between it and the overlying units (Nancy Member in Kentucky, Spickert Knob Formation in Indiana) (Rexroad, 1986).

Boundaries:

The boundaries are conformable (Rexroad, 1986).

Correlations:

According to Butts (1915) many Kenwood fossils are also common to the Keokuk Limestone of the upper Mississippi Valley (Rexroad, 1986). Recent studies, for example, by Kammer, Ausich, and Lane (1983), verify correlation of the Kenwood with part of the Keokuk (Rexroad, 1986).

Regional Indiana usage:

Illinois Basin Margin (COSUNA 12)
Supergroup: none
Group: Borden Group
Formation: New Providence Shale
Member: Kenwood Member
Cincinnati Arch (COSUNA 13)
Supergroup: none
Group: Borden Group
Formation: New Providence Shale
Member: Kenwood Member

Misc/Abandoned Names:

None

Geologic Map Unit Designation:

Mnpk

Note: Hansen (1991, p. 52) in Suggestions to authors of the reports of the United States Geological Survey noted that letter symbols for map units are considered to be unique to each geologic map and that adjacent maps do not necessarily need to use the same symbols for the same map unit. Therefore, map unit abbreviations in the Indiana Geologic Names Information System should be regarded simply as recommendations.

COSUNA areas and regional terminology

Names for geologic units vary across Indiana. The Midwestern Basin and Arches Region COSUNA chart (Shaver, 1984) was developed to strategically document such variations in terminology. The geologic map (below left) is derived from this chart and provides an index to the five defined COSUNA regions in Indiana. The regions are generally based on regional bedrock outcrop patterns and major structural features in Indiana. (Click the maps below to view more detailed maps of COSUNA regions and major structural features in Indiana.)

COSUNA areas and numbers that approximate regional bedrock outcrop patterns and major structural features in Indiana.

Major tectonic features that affect bedrock geology in Indiana.

References:

Butts, Charles, 1915, Geology and mineral resources of Jefferson County, Kentucky: Kentucky Geological Survey, ser. 4, v. 3, pt. 2, 270 p.

Hansen, W. R., 1991, Suggestions to authors of the reports of the United States Geological Survey (7^th ed.): Washington, D.C., U.S. Geological Survey, 289 p.

Kammer, T. W., Ausich, W. I., and Lane, N. G., 1983, Paleontology and stratigraphy of the Borden delta of southern Indiana and northern Kentucky (Field Trip 2), in Shaver, R. H., and Sunderman, J. A., eds., Field trips in midwestern geology: Bloomington, Indiana, Geological Society of America, Indiana Geological Survey, and Indiana University Department of Geology, p. 37–71.

Kepferle, R. C., 1977, Stratigraphy, petrology, and depositional environment of the Kenwood Siltstone Member, Borden Formation (Mississippian), Kentucky and Indiana: U.S. Geological Survey Professional Paper 1007, 49 p.

Rexroad, C. B., 1986, Kenwood Member, in Shaver, R. H., Ault, C. H., Burger, A. M., Carr, D. D., Droste, J. B., Eggert, D. L., Gray, H. H., Harper, Denver, Hasenmueller, N. R., Hasenmueller, W. A., Horowitz, A. S., Hutchison, H. C., Keith, B. D., Keller, S. J., Patton, J. B., Rexroad, C. B., and Wier, C. E., Compendium of Paleozoic rock-unit stratigraphy in Indiana–a revision: Indiana Geological Survey Bulletin 59, p. 68.

Rexroad, C. B., and Lane, N. G., 1984, Spickert Knob Formation (new), Borden Group, in Indiana: Indiana Geological Survey Occasional Paper 43, 4 p.

Shaver, R. H., coordinator, 1984, Midwestern basin and arches region–correlation of stratigraphic units in North America (COSUNA): American Association of Petroleum Geologists Correlation Chart Series.

Stockdale, P. B., 1931, The Borden (Knobstone) rocks of southern Indiana: Indiana Department of Conservation Publication No. 98, 330 p.