Age:

Ordovician

Type designation:

Type locality: The Whitewater Formation was named by Nickles (1903, p. 208) for exposures of bluish-gray rubbly limestone and interbedded calcareous shale along the Whitewater River at Richmond, Wayne County, Indiana (Burger, 1970; Gray, 1986).

History of usage:

As now recognized, the Whitewater includes at its base a dolomitic unit, the Saluda Member (Gray, 1972), and in its uppermost part shale and limestone formerly placed in the Elkhorn Formation (Utgaard and Perry, 1964; Gray, 1986).

Description:

The Whitewater Formation contains a somewhat higher proportion of limestone than does the underlying Dillsboro Formation, but this alone is not distinctive; it is the Saluda Member at its base that best distinguishes the Whitewater (Gray, 1986).

Traditionally, the Whitewater Formation is recognized in Indiana only in the classic Cincinnatian outcrop area in the southeastern part of the state and in the near subsurface. Within this area the formation thins southward from about 100 ft (30 m) near Richmond to about 60 ft (18 m) near Madison, where the formation is reduced to its basal Saluda Member (Gray, 1986). At the top of the Maquoketa Group in northeastern Indiana, however, Gray (1972, p. 18-20 and fig. 13) identified an informal working unit as much as 160 ft (50 m) thick that is stratigraphically equivalent to the Whitewater and that, because it is dominantly limestone, was assigned by Gray (1986) to the Whitewater Formation rather than to the laterally equivalent Brainard Shale. The Whitewater of northeastern Indiana rests, probably conformably, on the Fort Atkinson Limestone (Gray, 1986).

Near the top of the Whitewater in northeastern Indiana, especially in areas where the formation is thickest, are zones containing ferruginous reddish-brown ooids, beds of sedimentary iron ore, and limestone with hematitic cement (Gray, 1986). These have not been observed elsewhere in the Maquoketa in Indiana, but similar materials are found in the presumably correlative Neda Formation, which is at the top of the Maquoketa Group in northern Illinois (Kolata and Graese, 1983, p. 29; Gray, 1986). The Whitewater is the uppermost formation in the type Richmondian Stage, but its subsurface extension, where thickest, probably includes Ordovician rocks that are somewhat younger than any that are exposed in the Richmond area (Gray, 1972, p. 19-20; Gray, 1986).

Boundaries:

The Whitewater Formation conformably overlies the Dillsboro Formation (except as noted below) and is disconformably overlain by the Brassfield Limestone (Silurian) except in a few places in Clark, Jefferson, Ripley, and Decatur Counties, where the Brassfield is absent and the Osgood Member of the Salamonie Dolomite directly overlies the formation (Foerste, 1891, 1904; Brown and Lineback, 1966, p. 1,022; Nicoll and Rexroad, 1968; Gray, 1986). The disconformable nature of this contact is emphasized by reworked Ordovician fossils in the basal part of the Brassfield Limestone (Gray, 1986).

Regional Indiana usage:

Cincinnati Arch (COSUNA 13)
Supergroup: none
Group: Maquoketa Group
Formation: Whitewater Formation
Kankakee Arch (COSUNA 14)
Supergroup: none
Group: Maquoketa Group
Formation: Whitewater Formation

Misc/Abandoned Names:

Elkhorn Formation

Geologic Map Unit Designation:

Ow

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.

See also:

Brainard Shale

References:

Brown, G. D., Jr., and Lineback, J. A., 1966, Lithostratigraphy of Cincinnatian Series (Upper Ordovician) in southeastern Indiana: American Association of Petroleum Geologists Bulletin, v. 50, p. 1,018–1,023.

Burger, A. M., 1970, Whitewater Formation, 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. 191–192.

Foerste, A. F., 1891, The age of the Cincinnati Anticlinal: American Geologist, v. 7, p. 97–109.

Foerste, A. F., 1904, The Ordovician-Silurian contact in the Ripley Island area of southern Indiana, with notes on the age of the Cincinnati Geanticline: American Journal of Science, v. 4, p. 321–342.

Gray, H. H., 1972, Lithostratigraphy of the Maquoketa Group (Ordovician) in Indiana: Indiana Geological Survey Special Report 7, 31 p.

Gray, H. H., 1986, Whitewater Formation, 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. 168–169.

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.

Kolata, D. R., and Graese, A. M., 1983, Lithostratigraphy and depositional environments of the Maquoketa Group (Ordovician) in northern Illinois: Illinois State Geological Survey Circular 528, 49 p.

Nickles, J. M., 1903, The Richmond Group in Ohio and Indiana and its subdivisions, with a note on the genus Strophomena and its type: American Geologist, v. 32, p. 202–218.

Nicoll, R. S., and Rexroad, C. B., 1968, Stratigraphy and conodont paleontology of the Salamonie Dolomite and Lee Creek Member of the Brassfield Limestone (Silurian) in southeastern Indiana and adjacent Kentucky: Indiana Geological Survey Bulletin 40, 73 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.

Utgaard, John, and Perry, T. G., 1964, Trepostomatous bryozoan fauna of the upper part of the Whitewater Formation (Cincinnatian) of eastern Indiana and western Ohio: Indiana Geological Survey Bulletin 33, 111 p.