Type locality: The name “New Providence Shale” was used by Borden (1874, p. 161) for 80 to 100 ft (24 to 30 m) of shale "at the base of the knobs and immediately above the ferruginous [Rockford] limestone" (Rexroad, 1986).
History of usage:
Borden (1874) did not designate a type section, but he included rocks up to the "true knob shale," which is interpreted to be the Spickert Knob Formation of present use. The formation was named for New Providence, Floyd County, Indiana, but typical exposures "are not seen nearer than about four miles east of the town" (Stockdale, 1931, p. 85; Rexroad, 1986). Exposures are to be found in the lowlands and lowest part of the Knobstone Escarpment both north and south of Broomhill, which is in the southwest corner of sec. 5, T. 1 S., R. 6 E. (Rexroad, 1986). One of the best natural exposures of the New Providence is on the south end of Kenwood Hill in the southern part of Louisville, Jefferson County, Kentucky (Rexroad, 1986). This is the type section of the Kenwood Member of the New Providence Shale (Rexroad, 1986).
Greenish-gray, blue-gray, or dark-lead-gray shale bordering on claystone is the dominant lithology of the New Providence, although the Kenwood Member is a clayey, poorly sorted fine siltstone interbedded with shale similar to the rest of the New Providence (Rexroad, 1986). Ironstone lenses or beds generally less than 1 foot (0.3 m) thick and composed mainly of iron carbonate are irregularly distributed throughout most of the formation in southern Indiana (Rexroad, 1986). Both fossiliferous and unfossiliferous limestones are present as concretionary bands, beds, or biohermlike patches, but these are more common in Kentucky than in southern Indiana (Rexroad, 1986). Minor amounts of red shale are present, most commonly in the northern half of the outcrop area of the formation (Rexroad, 1986). To the north, beds of siliceous silty dolostone several feet thick are present in places (Rexroad, 1986).
The Rockford-New Providence contact is sharp, although the two apparently are conformable in northern Indiana (Rexroad, 1986). The contact is erosional in southern Indiana, and where the Rockford Limestone is absent the New Providence rests on the New Albany Shale (Rexroad, 1986). The boundary of the New Providence with the overlying Spickert Knob Formation is gradational and in part intertonguing, and therefore a contact is difficult to pick in many areas but is recognized on the basis of the upward change from a dominantly clay shale to a very silty shale (Rexroad, 1986).
Conodont studies (Rexroad and Scott, 1964) showed that the New Providence Shale is time transgressive and is oldest in its northern outcrop area where the lower part is equivalent to the lower part of the Burlington Limestone or the Fern Glen Formation of the Mississippi Valley and is a part of the Bactrognathus-Polygnathus communis Assemblage Zone (Rexroad, 1986). To the south the basal part of the New Providence is younger and correlates with part of the Keokuk of Iowa (Butts, 1915; Kammer, Ausich, and Lane, 1983; Kammer, 1984; Rexroad, 1986). The upper limit of the correlation is indefinite but is within the Keokuk (Rexroad, 1986). Rexroad (1986) noted that nowhere is the New Providence known to be of Kinderhookian age.
Regional Indiana usage:
Illinois Basin (COSUNA 11)
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.)
Borden, W. W., 1874, Report of a geological survey of Clark and Floyd Counties, Indiana: Indiana Geological Survey Annual Report 5, p. 133-189.
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 (7th ed.): Washington, D.C., U.S. Geological Survey, 289 p.
Kammer, T. W., 1984, Crinoids from the New Providence Shale Member of the Borden Formation (Mississippian) in Kentucky and Indiana: Journal of Paleontology, v. 58, p. 115-130.
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.
Rexroad, C. B., 1986, New Providence 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. 102-103.
Rexroad, C. B., and Scott, A. J., 1964, Conodont zones in the Rockford Limestone and the lower part of the New Providence Shale (Mississippian) in Indiana: Indiana Geological Survey Bulletin 30, 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.
Stockdale, P. B., 1931, The Borden (Knobstone) rocks of southern Indiana: Indiana Department of Conservation Publications 98, 330 p.
For additional information contact:
Nancy Hasenmueller (firstname.lastname@example.org)Date last revised: December 9, 2013