Age:

Pennsylvanian

Type designation:

Type section: Near the site of the former town of Alum Cave, Sullivan County, Indiana, in the NW¼NE¼ sec. 25, T. 9 N., R. 8 W. (See Burger and Wier, 1970.)

History of usage:

Named: The name “Alum Cave” was first used by Logan (1930, p. 168) in a columnar section for an indefinite interval of rock above the Springfield Coal Member in Sullivan County, Indiana (Burger and Wier, 1986).

Revised name: Logan's term was modified to "Alum Cave Limestone" by Wanless (1939, table 2) and restricted to the limestone above the coal, although Culbertson (1932) had called the same limestone "the Arthur Limestone" (Burger and Wier, 1986).

Revised rank: This limestone was designated as the Alum Cave Limestone Member by Wier (1950) and assigned, as the uppermost member, to the Petersburg Formation (Burger and Wier, 1986).

Revised assignment: The unit was later assigned, as the lowermost member, to the Dugger Formation by Wier in unpublished manuscripts and by Wier and Gray (1961) on the Indianapolis 1° X 2° Regional Geologic Map (Burger and Wier, 1986).

Description:

The Alum Cave Limestone Member is typically a medium- to blue-gray limestone that is fine grained, argillaceous, locally sandy, and fossiliferous (Burger and Wier, 1986). In most places the limestone is separated into two beds by a few inches of shale. The thickness of the limestone ranges from 0.1 to 11.8 ft (0.03 to 3.6 m); the average thickness is 2.8 ft (0.8 m) (Burger and Wier, 1970). It generally contains a fauna rich in crinoid columnals, brachiopods, gastropods, and pelecypods. Fusulinids and ostracods are present in places; trilobites are rare (Burger and Wier, 1986).

The Alum Cave Limestone Member lies 1 to 30 ft (0.3 to 9 m) above the Springfield Coal Member but is generally less than 6 ft (1.8 m) above this coal (Burger and Wier, 1970). The thickest exposures of the Alum Cave are in Sullivan and Greene Counties (Burger and Wier, 1986).

Distribution: The Alum Cave Limestone Member is not found in the subsurface in parts of western Sullivan County and Vigo County and cannot be identified in outcrop in northern Vigo County and Vermillion County (Burger and Wier, 1986). South of Sullivan County the limestone is thin and nodular. It can be traced as gray to brown calcareous fossiliferous shale containing limestone nodules as far south as Pike and Warrick Counties (Burger and Wier, 1986).

Correlations:

Burger and Wier (1986) suggested that the Alum Cave Limestone Member was correlative with the St. David Limestone Member of the Carbondale Formation in Illinois. Burger and Wier (1970) noted that the calcareous fossiliferous shale extended into Kentucky.

Brown, Rexroad, and Zimmerman (2016) correlated the Alum Cave with the St. David Limestone Member of the Carbondale Formation in Illinois on the basis of the Neognathodus Index (NI), which they use for Desmoinesian correlation purposes. The Neognathodus Index was 4.79 for the St. David of Illinois and within reasonable approximation of the Alum Cave (NI = 4.83). Thus, the Neognathodus Index supports the correlation of the St. David Limestone Member of Illinois with the Alum Cave, as suggested by Burger and Wier (1986).

Regional Indiana usage:

Illinois Basin (COSUNA 11)
Supergroup: none
Group: Carbondale Group
Formation: Dugger Formation
Member: Alum Cave Limestone Member
Illinois Basin Margin (COSUNA 12)
Supergroup: none
Group: Carbondale Group
Formation: Dugger Formation
Member: Alum Cave Limestone Member

Misc/Abandoned Names:

Arthur Limestone

Geologic Map Unit Designation:

Pdac

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:

Brown, L. M., Rexroad, C. B., and Zimmerman, A. N., 2016, Conodont paleontology of the Alum Cave Limestone Member of the Dugger Formation (Pennsylvanian, Desmoinesian) in the eastern part of the Illinois Basin: Indiana Geological Survey Occasional Paper 72, 25 p.

Burger, A. M., and Wier, C. E., 1970, Alum Cave Limestone Member, in Shaver, R. H., Burger, A. M., Gates, G. R., Gray, H. H., Hutchison, H. C., Keller, S. J., Patton, J. B., Rexroad, C. B., Smith, N. M., Wayne, W. J., and Wier, C. E., Compendium of rock-unit stratigraphy in Indiana: Indiana Geological Survey Bulletin 43, p. 4–5.

Burger, A. M., and Wier, C. E., 1986, Alum Cave Limestone 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. 4.

Culbertson, J. A., 1932, The paleontology and stratigraphy of the Pennsylvanian strata between Caseyville, Kentucky, and Vincennes, Indiana: Urbana, University of Illinois, Ph.D. thesis, 292 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.

Logan, W. N., 1930, The mineral fuel resources of Indiana: Indiana Year Book for 1929, p. 161–171.

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.

Wanless, H. R., 1939, Pennsylvanian correlations in the Eastern Interior and Appalachian coalfields: Geological Society of America Special Paper 17, 130 p.

Wier, C. E., 1950, Geology and coal deposits of the Jasonville quadrangle, Clay, Greene, and Sullivan Counties, Indiana: U.S. Geological Survey Coal Investigations Map C 1, scale 1:24,000.

Wier, C. E., and Gray, H. H., 1961, Geologic map of the Indianapolis 1° x 2° quadrangle, Indiana and Illinois, showing bedrock and unconsolidated deposits: Indiana Geological Survey Regional Geologic Map, Indianapolis Sheet, scale 1:250,000.