Age:

Pennsylvanian

Type designation:

Type section: Owen (1839, p. 8) and later Lesquereux (1862, p. 296-297) described this limestone unit, which is exposed in the high banks of the Ohio River at West Franklin in Posey County, Indiana (Wier, 1970; Wier and Ault, 1986).

Reference section: Gray (2011, p. 3) selected the Abraxas Petroleum No. 1 Durrell (Indiana Geological Survey Petroleum Database Management System No. 111840) sec. 18, T. 6 S., R. 13 W., to serve as a subsurface reference for the West Franklin Limestone Member. The drill hole lacks samples; however, it has a good suite of geophysical logs. The logs show three benches of the West Franklin Limestone at 212 to 260 ft (64.6 to 79.2 m) (Gray, 2011, p. 3-4, fig. 3).

History of usage:

The limestone exposed in the high banks of the Ohio River at West Franklin, Posey County, was first mentioned in the literature by Owen (1839, p. 8) and later by Lesquereux (1862, p. 296-297), who described the units exposed along the river and referred to them informally as the lower bank of the West Franklin Limestone (Wier, 1970; Wier and Ault, 1986). Wilmarth (1938, p. 2,307), however, gave credit for first use of the name to Collett (1884, p. 61-62), who also used the term “West Franklin Limestone” (Wier, 1970; Wier and Ault, 1986).

Wier and Gray (1961) and Wier (1970) reduced the rank of this limestone to that of member, uppermost in the Shelburn Formation, and Wier (1970) stated that the exposure at West Franklin in the SE¼SE¼ sec. 24, T. 7 S., R. 12 W., was the type locality (Wier, 1970; Wier and Ault, 1986), but the correct locality is in the NE¼SE¼ sec. 24 (Wier and Ault, 1986). The bedrock outcrop of the West Franklin was mapped by Gray, Wayne, and Wier (1970), Gray and others (1979), and Gray, Ault, and Keller (1987).

Synonyms of the West Franklin are the terms: “Somerville Limestone” used in Warrick County by Fuller and Ashley (1902, p. 2) (Wier, 1970, 1986), “Somerville Formation,” used in Gibson County by Fuller and Clapp (1904, p. 2) (Wier, 1970; Wier and Ault, 1986), and “Maria Creek Limestone,” used in Sullivan County by Malott (1948, p. 125) (Wier, 1970; Wier and Ault, 1986).

Description:

The West Franklin Limestone Member generally consists of limestone beds separated by shale (Wier, 1970; Wier and Ault, 1986). In Gibson County three beds of limestone are found, but northward only the upper two are present and in places only one limestone bed can be seen (Wier, 1970; Wier and Ault, 1986). The lowest bed is sparsely fossiliferous, ranges from 1 to 4 ft (0.3 to 1.2 m) in thickness, and is overlain by 1 to 25 ft (0.3 to 7.6 m) of tan, blue-gray, or variegated nonfossiliferous shale that in some places has an intercalated shale (Wier, 1970; Wier and Ault, 1986). The middle limestone is a massive light-gray to tan argillaceous fossiliferous limestone ranging from 4 to 10 ft (1.2 to 3 m) in thickness at the south end of the outcrop and thinning northward to 0.5 to 3.8 ft (0.2 to 1.2 m) of flaggy nodular limestone in Sullivan County (Wier, 1970; Wier and Ault, 1986). In Posey County it contains large colonies of the coral Chaetetes (Wier, 1970; Wier and Ault, 1986). Gray shale, 0.1 to 3 ft (< 0.1 to 0.9 m) thick, separates the middle limestone from the upper, more cherty limestone, which is gray to brown, dense, crystalline, argillaceous, and fossiliferous (Wier, 1970; Wier and Ault, 1986). The upper limestone is 1 to 6 ft (0.3 to 1.8 m) thick in Gibson, Vanderburgh, and Posey Counties and attains a maximum thickness of 10 ft (3 m) in Sullivan County (Wier, 1970; Wier and Ault, 1986).

In parts of the subsurface in Posey and Gibson Counties any one or more of the above three beds are not present, and drilling records indicate that some thin limestone beds are present in the shale, sandy shales, and sandstones 100 ft (30 m) or more beneath the normal stratigraphic interval of the West Franklin (Wier and Ault, 1986). This variation in the presence and the location of the limestone beds makes definition of the base of the West Franklin arbitrary in places (Wier and Ault, 1986; Gray, 2011).

Brown and Rexroad (2009) noted that in the southeastern part of the Illinois Basin the West Franklin Limestone Member of the Shelburn Formation was deposited in very shallow marine waters influenced by delta shifting, penecontemporaneous structural deformation, and small changes in sea level. They (2009) also noted that the Desmoinesian-Missourian boundary occurs within the member.

Distribution: In Indiana, the West Franklin Limestone extends from Posey and Vanderburgh Counties in the southwesternmost part of the state northward to the southernmost part of Vermillion County (Gray, 2011, fig. 2).

Boundaries:

The West Franklin Limestone overlies a thick clastic sequence of the Shelburn Formation (Brown and Rexroad, 2009, p. 2). The unit is generally overlain by unnamed clastic rocks of the Patoka Formation; however, in places, the Inglefield Sandstone Member of the Patoka directly overlies the West Franklin Limestone (Brown and Rexroad, 2009).

Correlations:

The West Franklin Limestone Member of the Shelburn Formation is recognized in Indiana and Kentucky (Brown and Rexroad, 2009). In Illinois, the West Franklin equivalents include the Piasa Limestone Member, the De Graff Coal Member, the Pond Creek Coal Member, and the Attila Shale Member of Desmoinesian age; and the Lake Creek Coal Member and locally an upper bench of the West Franklin of Missourian age; plus intervening unnamed units all of the Shelburn Formation (Brown and Rexroad, 2009, p. 20). The Desmoinesian-Missourian boundary, as established by palynomorphs and the termination of Neognathodus, occurs within the member (Brown and Rexroad, 2009, p. 20).

Regional Indiana usage:

Illinois Basin (COSUNA 11)
Supergroup: none
Group: McLeansboro Group
Formation: Shelburn Formation
Member: West Franklin Limestone Member
Illinois Basin Margin (COSUNA 12)
Supergroup: none
Group: McLeansboro Group
Formation: Shelburn Formation
Member: West Franklin Limestone Member

Misc/Abandoned Names:

Maria Creek Limestone, Somerville Formation, Somerville Limestone

Geologic Map Unit Designation:

*shwf

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., and Rexroad, C. B., 2009, Conodont paleontology of the West Franklin Limestone Member of the Shelburn Formation (Pennsylvanian) in the southeastern part of the Illinois Basin: Indiana Geological Survey Special Report 68, 34 p.

Collett, John, 1884, Geology of Posey County: Indiana Department of Geology and Natural History Annual Report 13, pt. 1, p. 45–70.

Fuller, M. L., and Clapp, F. G., 1904, Description of the Patoka quadrangle: U.S. Geological Survey Geologic Atlas, Folio 105, 12 p.

Gray, H. H., 2011, Stratigraphy of the West Franklin Limestone Member (Pennsylvanian) in Posey County, Indiana: Indiana Geological Survey Special Report 70, 15 p.

Gray, H. H., Ault, C. H., and Keller, S. J., 1987, Bedrock geologic map of Indiana: Indiana Geological Survey Miscellaneous Map 48, scale 1:500,000.

Gray, H. H., Bleuer, N. K., Hill, J. R., and Lineback, J. A., 1979, Geologic map of the 1° x 2° Indianapolis quadrangle, Indiana and Illinois, showing bedrock and unconsolidated deposits: Indiana Geological Survey Regional Geologic Map No. 1, Part A [bedrock units], scale 1:250,000.

Gray, H. H., Wayne, W. J., and Wier, C. E., 1970, Geologic map of the 1° x 2° Vincennes quadrangle and parts of adjoining quadrangle, Indiana and Illinois, showing bedrock and unconsolidated deposits: Indiana Geological Survey Regional Geologic Map No. 3, Part A [bedrock units], scale 1:250,000.

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.

Lesquereux, Leo, 1862, Report on the distribution of the geological strata in the Coal Measures of Indiana, in Owen, Richard, Report of a geological reconnaissance of Indiana, made in the years 1859 and 1860, under the direction of the late David Dale Owen, M. D., State Geologist: Indianapolis, Indiana, H. H. Dodd and Co., p. 269–341.

Malott, C. A., 1948, The geology of the Dicksburg Hills, Knox County, Indiana: Indiana Academy of Science Proceedings, v. 57, p. 125–141.

Owen, D. D., 1839, Second report of a geological survey of Indiana, made in the year 1838, in conformity to an order of the legislature: Indiana Senate Journal for 1838-39, p. 198–241: Indianapolis, Osborn and Willets, 54 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, Ditney Coal 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. 48–49.

Wier, C. E., 1970, West Franklin 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. 190–191.

Wier, C. E., 1986, Ditney Coal 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. 38.

Wier, C. E., and Ault, C. H., 1986, West Franklin 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. 168.

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.

Wilmarth, M. G., 1938, Lexicon of geologic names of the United States (including Alaska): U.S. Geological Survey Bulletin 896, 2,396 p.