Age:

Pennsylvanian

Type designation:

Type section: The term “Pinnick Coal” was first used by Franklin (1939, p. 9-10) for the coal bed exposed in a small mine opening west of Thomas Pinnick's house in the SE¼SW¼ sec. 32, T. 2 N., R. 2 W., Orange County, Indiana (Hutchison, 1970, 1986).

History of usage:

The coal was given the rank of member in the Mansfield Formation by Gray, Jenkins, and Weidman (1960, p. 26) (Hutchison, 1970, 1986).

Description:

The Pinnick Coal Member at the mine mentioned above was described by Franklin as shiny, blocky, and 2.1 ft (0.6 m) thick (Hutchison, 1970, 1986). This coal bed is generally less than 1 ft (0.3 m) thick and is difficult to trace (Hutchison, 1970, 1986). The roof of the coal is carbonaceous shale or massive medium-grained ferruginous sandstone, and the floor is underclay (Hutchison, 1970, 1986). The Pinnick coal lies immediately above the so-called "Hindostan Whetstone Beds," and in the area where it is thickest, it is some 50 to 185 ft (15 to 56 m) above the base of the Mansfield Formation (Gray, Jenkins, and Weidman, 1960, p. 24; Hutchison, 1964, 1967, and 1971; Hutchison, 1970, 1986).

Correlations:

The Pinnick has been mapped in northwestern Orange County (Gray, Jenkins, and Weidman, 1960, pl. 1), Dubois County (Hutchison, 1964), and Martin County (Hutchison, 1967) (Hutchison, 1970, 1986). Correlations with other named coal beds in the Mansfield Formation to the north and the south of this area have not been established (Hutchison, 1970, 1986).

Regional Indiana usage:

Illinois Basin (COSUNA 11)
Supergroup: none
Group: Raccoon Creek Group
Formation: Mansfield Formation
Member: Pinnick Coal Member
Illinois Basin Margin (COSUNA 12)
Supergroup: none
Group: Raccoon Creek Group
Formation: Mansfield Formation
Member: Pinnick Coal Member

Misc/Abandoned Names:

None

Geologic Map Unit Designation:

*mp

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:

Franklin, D. W., 1939, Lithologic and stratigraphic study of the Lower Pennsylvanian strata, Orange County, Indiana: Urbana, University of Illinois, master's thesis, 49 p.

Gray, H. H., Jenkins, R. D., and Weidman, R. M., 1960, Geology of the Huron area, south-central Indiana: Indiana Geological Survey Bulletin 20, 78 p.

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.

Hutchison, H. C., 1964, Distribution, structure, and mined areas of coals in Dubois County, Indiana: Indiana Geological Survey Preliminary Coal Map 10, scale 1:126,720.

Hutchison, H. C., 1967, Distribution, structure, and mined areas of coals in Martin County, Indiana: Indiana Geological Survey Preliminary Coal Map 11, scale 1:126,720.

Hutchison, H. C., 1970, Pinnick 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. 133.

Hutchison, H. C., 1971, Distribution, structure, and mined areas of coals in Daviess County, Indiana: Indiana Geological Survey Preliminary Coal Map 15, scale 1:126,720.

Hutchison, H. C., 1986, Pinnick 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. 113.

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.