Type locality: The name "Carthage" was first used in 1856 (Owen, p. 60) for a limestone exposed along the bank of the Ohio River 1 mile (1.6 km) west of Uniontown, Union County, western Kentucky (Carr, 1986). It was named for Carthage Settlement, which is no longer in existence (Carr, 1986).
History of usage:
Overview: The Carthage is equivalent to the Shoal Creek Limestone Member, a name introduced by Engelmann (1868, p. 175) for a limestone exposed along Shoal Creek in Clinton County, Illinois (Carr, 1986). Although the name "Shoal Creek" was extended in 1961 (Wier and Gray) to Indiana, it was later discontinued in deference to "Carthage" (Jacobson and others, 1985) for use throughout the Illinois Basin (Carr, 1986).
The Carthage in Indiana is a bluish- to brownish-gray, finely crystalline fossiliferous limestone that generally occurs in a single bed 2 to 4 ft (0.6 to 1.2 m) thick (Wier, 1970). Where it has been measured in cores in Posey County the Carthage is 5 to 6 ft (1.5 to 1.8 m) thick, but it thins to less than a foot to the north in Sullivan County (Carr, 1986). The Carthage is about 8 ft (2.4 m) thick at the type section in Kentucky, and it is commonly 6 to 8 ft (1.8 to 2.4 m) thick at the reference section in Illinois (Carr, 1986).
In many places it overlies a black fissile shale and the Parker Coal Member (Patoka Formation) (Carr, 1986).
Brown, Rexroad, and Johnston (1994) studied core material of the Carthage Limestone from a small area in western Kentucky to determine conodont distribution and to interpret paleoenvironments by biofacies analysis. They noted (1994) that the Carthage conodonts are dominated by Idiognathodus and Streptognathodus.
Regional Indiana usage:
Illinois Basin (COSUNA 11)
Shoal Creek Limestone Member
Geologic Map Unit Designation:
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.
Brown, L. M., Rexroad, C. B., and Johnston, K. W., 1994, Conodonts from the Carthage Limestone Member, Bond Formation (Missourian, Pennsylvanian) of Webster and Union Counties, western Kentucky [abs.]: Geological Society of America Abstracts with Programs, North-Central Section, v. 26, no. 5, p. 6.
Carr, D. D., 1986, Carthage 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. 27.
Engelmann, Henry, 1868, Geology of Clinton and Washington Counties, in Geology and paleontology: Illinois State Geological Survey, v. 3, p. 145–191.
Hansen, W. R., 1991, Suggestions to authors of the reports of the United States Geological Survey (7th ed.): Washington, D.C., U.S. Geological Survey, 289 p.
Jacobson, R. J., Trask, C. B., Ault, C. H., Carr, D. D., Gray, H. H., Hasenmueller, W. A., Williams, D., and Williamson, A. D., 1985, Unifying nomenclature in the Pennsylvanian System of the Illinois Basin: Illinois State Academy of Science Transactions, v. 78, p. 1–11.
Kosanke, R. M., Simon, J. A., Wanless, H. R., and Willman, H. B., 1960, Classification of the Pennsylvanian strata of Illinois: Illinois State Geological Survey Report of Investigations 214, 84 p.
Owen, D. D., 1856, Report of the geological survey in Kentucky, made during the years 1854 and 1855: Frankfort, Ky., 416 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.
Wier, C. E., 1970, Shoal Creek 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. 165–166.
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.
For additional information, contact:
Nancy Hasenmueller (firstname.lastname@example.org)Date last revised: November 30, 2016