Age:

Devonian

Type designation:

Type area: The name "Antrim Shale" was proposed for the shale unit exposed 1 mile (1.6 km) south of Norwood along Lake Michigan in Antrim County, Michigan (Lane, 1901).

History of usage:

Extended: The name "Antrim" was introduced by Lineback (1968) for the rocks that are north of the Kankakee and Cincinnati Arches in Indiana and that are mostly coextensive with the Antrim of the Michigan type area (Hasenmueller, 1986).

Description:

The Antrim Shale in Indiana is predominantly brownish-black noncalcareous shale; however, in some places a medium-gray calcareous shale or limestone is in the lower part of the unit (Hasenmueller, 1986). In some areas in western LaPorte County a thin bed of fine-grained quartz sandstone is at the base of the Antrim (Hasenmueller, 1986). The Antrim Shale ranges from 60 ft (18 m) to more than 220 ft (67 m) in thickness and in Indiana attains maximum thicknesses in southeastern Lagrange County and northern Steuben County (Hasenmueller and Bassett, 1979). The gray calcareous shale in the lower part of the Antrim thickens from 0 ft in western LaPorte County to more than 50 ft (15 m) in Elkhart County (Hasenmueller and Bassett, 1981).

Distribution: The Antrim is at the bedrock surface as far west as Lake County and as far south as Pulaski County (Schneider and Keller, 1970); however, it is not exposed in Indiana because of the thick cover of glacial drift (Hasenmueller, 1986).

Boundaries:

The Antrim Shale paraconformably overlies the Traverse Formation. The Antrim underlies the Ellsworth Shale and the Antrim-Ellsworth boundary is generally placed at the base of the lowest greenish-gray shale bed (Hasenmueller, 1986, p. 42).

Correlations:

The fossil Protosalvinia (Foerstia) has been recognized in the Antrim Shale of Michigan (Hasenmueller and others, 1983; Matthews, 1983). It has also been found about 20 ft (6.1 m) above the base of the Clegg Creek Member of the New Albany Shale in southeastern Indiana (Hasenmueller, 1982) and in core samples of the Clegg Creek and the Grassy Creek Members of the New Albany from Indiana and western Kentucky (Hasenmueller and others, 1994). The gray calcareous shale in the lower part of the Antrim Shale in northern Indiana is considered equivalent to the upper part of the Traverse Group in Michigan (Schneider and Keller, 1970). These correlations suggest that the Antrim of northern Indiana is equivalent to the Blocher, Selmier, Morgan Trail, and Camp Run Members and at least part of the Clegg Creek Member of the New Albany Shale in the Illinois Basin (Hasenmueller, 1986).

Regional Indiana usage:

Kankakee Arch (COSUNA 14)
Supergroup: none
Group: none
Formation: Antrim Shale
Michigan Basin (COSUNA 15)
Supergroup: none
Group: none
Formation: Antrim Shale

Misc/Abandoned Names:

Genesee Shale

Geologic Map Unit Designation:

Da

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:

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.

Hasenmueller, N. R., 1982, Resource assessment of the New Albany Shale (Devonian and Mississippian) in southeastern Indiana–preliminary report, in Eastern Oil Shale Symposium Proceedings, 1981: Lexington, University of Kentucky and Institute for Mining and Minerals Research, p. 173–180.

Hasenmueller, N. R., 1986, Antrim Shale, 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. 5.

Hasenmueller, N. R., 1986, Ellsworth Shale, Ellsworth 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. 42–43.

Hasenmueller, N. R., and Bassett, J. L., 1979, Maps of northern Indiana showing thicknesses of the Sunbury, Ellsworth, and Antrim Shales (New Albany Shale equivalents): Morgantown, W. Va., U.S. Department of Energy, Morgantown Energy Technology Center, METC\EGSP Series No. 806 [1980].

Hasenmueller, N. R., and Bassett, J. L., 1981, Stratigraphy, in Hasenmueller, N. R., and Woodard, G. S., eds., Studies of the New Albany Shale (Devonian and Mississippian) and equivalent strata in Indiana: Indiana Geological Survey, p. 5–32.

Hasenmueller, N. R., Boberg, W. S., Lumm, C. B., Frankie, W. T., Hamilton-Smith, T., and Comer, J. B., 1994, Stratigraphy, in Hasenmueller, N. R., and Comer, J. B., eds., Gas potential of the New Albany Shale (Devonian and Mississippian) in the Illinois Basin: Indiana Geological Survey, Illinois Basin Consortium Illinois Basin Studies 2, p. 13–22.

Hasenmueller, N. R., Kepferle, R. C., Matthews, R. D., and Pollock, Don, 1983, Foerstia (Protosalvinia) in Devonian shales of the Appalachian, Illinois, and Michigan Basins, eastern United States, in Eastern Oil Shale Symposium Proceedings, 1983: Lexington, University of Kentucky and Institute for Mining and Minerals Research, p. 41–58.

Lane, A. C., 1901, Suggested changes in nomenclature in Michigan formations: Michigan Miner, v. 3, no. 10, p. 9.

Lineback, J. A., 1968, Subdivisions and depositional environments of New Albany Shale (Devonian-Mississippian) in Indiana: American Association of Petroleum Geologists Bulletin, v. 52, p. 1,291–1,303.

Matthews, R. D., 1983, Foerstia from the Antrim Shale (Devonian) of Michigan: Geology, v. 11, p. 327–330.

Schneider, A. F., and Keller, S. J., 1970, Geologic map of the 1° x 2° Chicago quadrangle, Indiana, Illinois, and Michigan, showing bedrock and unconsolidated deposits: Indiana Geological Survey Regional Geologic Map No. 4, Part A [bedrock units], scale 1:250,000.

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.