Age:

Mississippian

Type designation:

Type section: The name “Jacobs Chapel Shale” was applied by Campbell (1946, p. 855-856) to less than 1 ft (0.3 m) of greenish plastic shale overlying black shale of the New Albany Shale and underlying the Rockford Limestone in southern Indiana (Rexroad, 1970, 1986). The best exposure in the area near Jacobs Chapel Church and School is about 0.75 miles (1.2 km) northwest of Jacobs Chapel Church in the banks of Lewis Branch on the line between lots 86 and 107, Clark's Grant, Floyd County, Indiana (Rexroad, 1970, 1986).

History of usage:

The Jacobs Chapel is now recognized as the uppermost bed of the Clegg Creek Member (Lineback, 1968, 1970) and of the Ellsworth Member (Hasenmueller and Bassett, 1981) of the New Albany Shale (Rexroad, 1986).

Description:

The Jacobs Chapel is a plastic greenish to dark-green glauconitic, sparsely fossiliferous shale. It is similar to some shale beds lower in the New Albany but contains more glauconite and calcite, so that earlier the Jacobs Chapel was interpreted as a basal phase of the Rockford Limestone (for example, Huddle, 1934; Rexroad, 1970, 1986).

Distribution: Exposures of the Jacobs Chapel Bed have been recognized in Scott, Clark, and Floyd Counties, where its thickness is generally between 0.2 and 0.6 foot (0.06 and 0.18 m), although the bed is absent from some places (Rexroad, 1970, 1986). In the subsurface the bed is too thin to be recognized on most conventional geophysical logs (Rexroad, 1986). It has been recognized, however, in cores as far north as Marion County (Hasenmueller and Bassett, 1981) and has also been recognized in southeastern Illinois by Cluff and others (1981), who extended the use of the name "Jacobs Chapel Bed" into Illinois (Rexroad, 1986).

Boundaries:

Rexroad (1986) noted that the abrupt lithologic changes at both the top and the bottom of the Jacobs Chapel Bed suggested brief hiatuses.

Correlations:

The Jacobs Chapel Bed belongs in the Kinderhookian Series and correlates with part of the Hannibal Shale of the Mississippi Valley (Rexroad, 1986). It also correlates within the lower part of the Coldwater Shale of northern Indiana and adjacent Michigan (Rexroad, 1986). The conodonts are only slightly older than those of the Siphonodella isoticha-S. cooperi Assemblage Zone in the overlying Rockford Limestone, but a precise correlation with the Mississippi Valley standards is not feasible (Rexroad, 1969; Rexroad, 1986).

Regional Indiana usage:

Illinois Basin Margin (COSUNA 12)
Supergroup: none
Group: none
Formation: New Albany Shale
Member: Clegg Creek Member
Bed: Jacobs Chapel Bed
Cincinnati Arch (COSUNA 13)
Supergroup: none
Group: none
Formation: New Albany Shale
Member: Clegg Creek Member
Bed: Jacobs Chapel Bed
Kankakee Arch (COSUNA 14)
Supergroup: none
Group: none
Formation: New Albany Shale
Member: Clegg Creek Member
Bed: Jacobs Chapel Bed

Misc/Abandoned Names:

None

Geologic Map Unit Designation:

Mnajc

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:

Campbell, Guy, 1946, New Albany Shale: Geological Society of America Bulletin, v. 57, p. 829–908.

Cluff, R. M., Reinbold, M. L., and Lineback, J. A., 1981, The New Albany Shale Group of Illinois: Illinois State Geological Survey Circular 518, 83 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.

Hasenmueller, N. R., and Bassett, J. L., 1981, Stratigraphy, in Hasenmueller, N. R., and Woodard, G. S., eds., Studies of the New Albany Shale (Devonian and Mississippian) and equivalent strata in Indiana: Indiana Geological Survey, p. 5–32.

Huddle, J. W., 1934, Conodonts from the New Albany Shale of Indiana: Bulletins of American Paleontology, v. 21, no. 72, 136 p.

Lineback, J. A., 1968, Subdivisions and depositional environments of New Albany Shale (Devonian-Mississippian) in Indiana: American Association of Petroleum Geologists Bulletin, v. 52, p. 1,291–1,303.

Lineback, J. A., 1970, Stratigraphy of the New Albany Shale in Indiana: Indiana Geological Survey Bulletin 44, 73 p.

Rexroad, C. B., 1969, Conodonts from the Jacobs Chapel Bed (Mississippian) of the New Albany Shale in southern Indiana: Indiana Geological Survey Bulletin 41, 55 p.

Rexroad, C. B., 1970, Jacobs Chapel Bed, 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. 76.

Rexroad, C. B., 1986, Jacobs Chapel Bed, 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. 63–64.

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.