IGNIS
New Harmony Group

Age:

Devonian

Type designation:

Type section: The name "New Harmony Group" was given by Becker and Droste (1978, p. 4) to the subsurface Lower Devonian rocks that are penetrated between the depths of 4,987 and 5,478 ft (4,996 and 5,480 ft on electric log) (1,521 and 1,671 m) in the Superior No. C-17 Ford well, White County, Illinois (Droste and Shaver, 1986).

History of usage:

Data for this section are available in Collinson and others (1967), Schwalb (1975), and Droste and Shaver (1987), and samples are on file in the Indiana Geological Survey as well as elsewhere (Droste and Shaver, 1986). The name is taken from New Harmony, Posey County, Indiana, which is very near the Ford well and on the east bank of the Wabash River (Droste and Shaver, 1986). The group was defined to include in generally ascending order the Grassy Knob Chert, Backbone Limestone, and Clear Creek Chert (Droste and Shaver, 1986).

Description:

The New Harmony consists of two basic kinds of variably colored, mostly pale carbonate rocks: (1) very fine grained to medium-grained, sparsely cherty limestone and dolostone to almost pure chert and (2) very light colored medium- to coarse-grained high-purity bioclastic limestone and dolostone (Droste and Shaver, 1986). The former are in more central Illinois Basin locations and consist of the Grassy Knob and Clear Creek Cherts, whereas the latter are the Backbone Limestone in the more basin-marginal area (Droste and Shaver, 1986). Each basic facies has tongues of the other facies (Droste and Shaver, 1986).

Distribution: In Indiana the New Harmony Group is limited to the subsurface in an area of about eight-county size in the southwesternmost part of the state (Becker, 1974, fig. 11), where it ranges from a northeastern eroded edge to almost 900 ft (274 m) in thickness in Posey County (Droste and Shaver, 1986). (See Becker and Droste, 1978, fig. 4A, and Droste and Shaver, 1987, fig. 8.)

Boundaries:

The base of the group in Indiana is the probably conformable contact between 20 to 30 ft (6 to 9 m) of white coarse-grained bioclastic limestone (above) and the drab fine-grained Bailey Limestone (Silurian, below) (Droste and Shaver, 1986). The New Harmony underlies the sandy dolostone of the Dutch Creek Sandstone Member (Jeffersonville Limestone, mostly Middle Devonian in age) or underlies Jeffersonville rocks unnamed to member where the Dutch Creek is not recognized (Droste and Shaver, 1986). This contact ranges from conformable (southwestward) to unconformable (northeastward) (Droste and Shaver, 1986). (See Shaver, 1984.)

Correlations:

Faunal data from the subsurface New Harmony are sparse but include records of a Devonian conodont species, Icriodus latericrecens huddlei (as reported by Becker, 1974, p. 24-28), that is common to the Oriskany Sandstone (Ulsterian) of New York (Droste and Shaver, 1986). The bottom part of the New Harmony Group, in its extension in Illinois to include uppermost rocks of the Bailey Limestone (as defined there), contains the conodont Icriodus woschmidti, which denotes a Gedinnian age in global terms (early Ulsterian, American terms) (Droste and Shaver, 1986). (See Becker and Droste, 1978, p. 4-5.) These and other fossils (not recorded in Indiana, however) suggest an age range from Gedinnian to Emsian inclusive (Ulsterian) (Droste and Shaver, 1986).

Regional Indiana usage:

Illinois Basin (COSUNA 11)
Supergroup: none
Group: New Harmony Group

Misc/Abandoned Names:

None

Geologic Map Unit Designation:

Dnh

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.)

Map showing the COSUNA areas (heavy black line) that approximate regional bedrock outcrop patterns and major structural features in Indiana, and the COSUNA numbers (large bold font) for these areas. The COSUNA boundaries are limited to state and county boundaries that facilitate coding.

COSUNA areas and numbers that approximate regional bedrock outcrop patterns and major structural features in Indiana.

Map showing major tectonic features that affect bedrock geology in Indiana.

Major tectonic features that affect bedrock geology in Indiana.

References:

Becker, L. E., 1974, Silurian and Devonian rocks in Indiana southwest of the Cincinnati Arch: Indiana Geological Survey Bulletin 50, 83 p.

Becker, L. E., and Droste, J. B., 1978, Late Silurian and Early Devonian sedimentologic history of southwestern Indiana: Indiana Geological Survey Occasional Paper 24, 14 p.

Collinson, Charles, James, G. W., Swann, D. H., Becker, L. E., Carlson, M. P., Dorheim, F. H., and Koenig, J. W., 1967, Devonian of north-central region, United States, in International symposium on the Devonian System: Alberta Society of Petroleum Geologists, v. 1, p. 933-971.

Droste, J. B., and Shaver, R. H., 1986, New Harmony Group, 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. 102.

Droste, J. B., and Shaver, R. H., 1987, Upper Silurian and Lower Devonian stratigraphy of the central Illinois Basin: Indiana Geological Survey Special Report 39, 29 p.

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.

Schwalb, H. R., 1975, Oil and gas in Butler County, Kentucky: Kentucky Geological Survey, ser. 10, Report of Investigations 16, 65 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.



For additional information contact:

Nancy Hasenmueller (hasenmue@indiana.edu)
Date last revised: July 28, 2014

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