Type section: The name Joachim Dolomite was introduced by Winslow in 1894 (p. 331, 352). The unit is exposed along Plattin Creek in Jefferson County, Missouri.
Where fully developed the Joachim consists of three divisions (Droste and Patton, 1986). The lowest unit consists typically of very fine grained to fine-grained argillaceous dark to light-colored dolostone and limestone (Droste, Abdulkareem, and Patton, 1982; Droste and Patton, 1986). Thin beds of silty to sandy dolostone and dolomitic fine- to medium-grained sandstone provide evidence for the St. Peter-Joachim facies relationship (Droste, Abdulkareem, and Patton, 1982; Droste and Patton, 1986). Where the Joachim overlies the Dutchtown Formation, the darker Joachim rocks grade downward into lighter colored Dutchtown rocks (Droste and Patton, 1986). This part of the Joachim ranges from 0 to 70 ft (0 to 21 m) in thickness (Droste and Patton, 1986).
The Joachim Dolomite is the upper formation of the Ancell Group except in a well in extreme northwestern Indiana where the St. Peter constitutes the entire Ancell Group (Droste and Patton, 1986).
The Joachim in Indiana is a lateral equivalent of upper St. Peter rocks in Indiana (Droste and Patton, 1986). Further, it correlates with the Joachim Dolomite of Illinois and Kentucky and with the lowest part of the Black River Limestone of Ohio (as described by Stith, 1979), and it is stratigraphically equivalent to the upper part of the St. Peter Sandstone and of the Glenwood Formation in Illinois and Michigan (Droste and Shaver, 1983; Shaver, 1984; Droste and Patton, 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 features in Indiana.
Major tectonic features that affect bedrock geology in Indiana.
Droste, J. B., and Patton, J. B., 1986, Joachim Dolomite, 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. 66–67.
Gutschick, R. C., 1983, Geology of the Kentland Dome structurally complex anomaly–northwestern Indiana (Field Trip 5), 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, v. 1., p. 105–138.
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.
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.
Stith, D. A., 1979, Chemical composition, stratigraphy, and depositional environments of the Black River Group (Middle Ordovician), southwestern Ohio: Ohio Geological Survey Report of Investigations 113, 36 p.
Templeton, J. S., and Willman, H. B., 1963, Champlainian Series (Middle Ordovician) in Illinois: Illinois State Geological Survey Bulletin 89, 260 p.
Winslow, Arthur, 1894, Lead and zinc deposits: Missouri Geological Survey, v. 6, 387 p.
For additional information, contact:
Nancy Hasenmueller (email@example.com)Date last revised: October 27, 2014