- Usage in publication:
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- Dargan Member
- Modifications:
-
- Named
- Dominant lithology:
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- Dolomite
- Limestone
- AAPG geologic province:
-
- Appalachian basin
Summary:
Named the Dargan Member of the Tomstown Formation for village of Dargan, Washington Co., MD. Unit extends northward into southern PA. Consists of interbedded, dark-gray, bioturbated dolomite, medium- to dark-gray, laminated dolomite, and dark-gray limestone. Thickness is 600 to 700 feet. Overlies the Benevola Member of the Tomstown and underlies the Red Run Member of the Waynesboro Formation. Lower contact placed in gradational zone where massive dolomite of the underlying Benevola is interbedded with thinly laminated dolomite of the Dargan. Upper contact placed at base of first 3-foot-thick shale interval of the Waynesboro. The Dargan is of Early Cambrian age.
Source: GNU records (USGS DDS-6; Reston GNULEX).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).