Type locality: Exposures near Glen Dean, Breckinridge County, Kentucky, were named the Glen Dean Limestone by Butts (1917, p. 97-102) (Gray, 1970; Gray and Horowitz, 1986).
History of usage:
The Glen Dean Limestone, as defined by Butts (1917, p. 97-102), consisted in descending order of 40 to 100 ft (12 to 30 m) of gray and red shale and thin beds of limestone, 30 to 60 ft (9 to 18 m) of gray crinoidal limestone, and as much as 10 ft (3 m) of red and green shale (Gray, 1970; Gray and Horowitz, 1986).
The Glen Dean Limestone is a thick-bedded skeletal to oolitic to biomicritic limestone (Gray, 1970; Gray and Horowitz, 1986). In Indiana the greatest known thickness of the Glen Dean Limestone is about 55 ft (16.8 m) in the shallow subsurface in southern Perry County (Droste and Keller, 1995). Throughout most of the subsurface in Indiana the formation ranges from 20 to 30 ft (6.1 to 9.1 m) in thickness (Droste and Keller, 1995).
The Glen Dean Limestone conformably overlies the Hardinsburg Formation and is overlain with apparent conformity by the Tar Springs Formation or disconformably by the Mansfield Formation (Pennsylvanian) (Gray, 1970; Gray and Horowitz, 1986).
Although the name "Glen Dean" is applied throughout the Illinois Basin, the upper boundary of the Glen Dean is not consistently defined (Gray and Horowitz, 1986). In the subsurface of southwestern Indiana, a widely recognized limestone unit about 10 ft (3 m) thick and a little above the so-called main Glen Dean is commonly called the upper Glen Dean (Gray and Horowitz, 1986). This unit is thicker in Illinois where it is assigned to the Glen Dean proper and in places is a major part of the formation (Gray and Horowitz, 1986). In Kentucky an upper unit of variable thickness consisting of shale and thin beds of limestone and sandstone is retained in the Glen Dean (Gray and Horowitz, 1986).
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.)
COSUNA areas and numbers that approximate regional bedrock outcrop patterns and major structural featuers in Indiana.
Major tectonic features that affect bedrock geology in Indiana.
Butts, Charles, 1917, Mississippian formations of western Kentucky: Descriptions and correlations of the Mississippian formations of western Kentucky: Kentucky Geological Survey, ser. 4, v. 5, pt. 1, 119 p.
Collinson, Charles, Rexroad, C. B., and Thompson, T. L., 1971, Conodont zonation of the North American Mississippian: Geological Society of America Memoirs 127, p. 353-394.
Gray, H. H., 1970, Glen Dean Limestone, 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. 64-65.
Gray, H. H., and Horowitz, A. S., 1986, Glen Dean Limestone, 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. 52-53.
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.
Horowitz, A. S., and Strimple, H. L., 1974, Chesterian echinoderm zonation in eastern United States: Septieme Congres International de Stratigraphie et de Geologie du Carbonifere Krefeld, August 23-28, 1971, Compte rendu, v. 3, p. 209-220.
Horowitz, A. S., Mamet, B. L., Neves, R., Potter, P. E., and Rexroad, C. B., 1979, Carboniferous paleontological zonation and intercontinental correlation of the Fowler No. 1 Traders core, Scott County, Tennessee, U.S.A.: Southeastern Geology, v. 20, p. 205-228.
Malott, C. A., and Thompson, J. D., Jr., 1920, The stratigraphy of the Chester Series of southern Indiana [abs.]: Science, new ser., v. 51, p. 521-522.
Mamet, B. L., and Skipp, B. A., 1971, Lower Carboniferous calcareous Foraminifera–preliminary zonation and stratigraphic implications for the Mississippian of North America: Sixieme Congres International de Stratigraphie et de Geologie du Carbonifere Sheffield, 1967, Compte rendu, v. 3, p. 1,129-1,146.
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.
For additional information, contact:
Nancy Hasenmueller (firstname.lastname@example.org)Date last revised: March 4, 2021