- Usage in publication:
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- Hiram Member*
- Modifications:
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- [Overview]
- Dominant lithology:
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- Amphibolite
- AAPG geologic province:
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- Piedmont-Blue Ridge province
GNU Staff, 1990, Draft copy of Higgins, M.W., and others, Geologic map of the Atlanta, Georgia 30-minute x 60-minute quadrangle, USGS Misc. Geol. Inv. Ser. Map I-2602 (published 2003): U.S. Geological Survey Digital Data Series, DDS-6, 1 CD-ROM., release 3
Summary:
[Early draft of M.W. Higgins and others' geol. map of Atlanta 30- x 60-minute quadrangle. In the published quadrangle (USGS Geol. Inv. Map I-2602, 2003; see also USGS OF-98-245, 1998), Hiram Member of Ropes Creek Metabasalt not used. These rocks are called unnamed amphibolite.]
Named as a member of the Ropes Creek Metabasalt in the Atlanta 1:100,000-scale quadrangle, GA. Named for town of Hiram. Type section is along the road parallel to Seaboard Coast Line railroad tracks from BM 1028 to the Popular Springs Church in the town of Hiram, Dallas 7.5-minute quadrangle. Consists of fine- to medium-grained, dark-green to greenish-black, ocher-weathering, massive to finely layered, locally laminated, pillowed, chloritic, garnetiferous amphibolite. Final weathering product is dark-red clayey soil. Contains 5 to 20 percent interlayered white-weathering potassium-feldspar-poor gneisses. Age is Cambrian.
Source: Modified from GNU records (USGS DDS-6; Reston GNULEX).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.
"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 does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).