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  • Usage in publication:
    • Villa Rica Gneiss Member
  • Modifications:
    • Named
  • Dominant lithology:
    • Gneiss
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Abrams, C.E., and McConnell, K.I., 1981, Stratigraphy of the area around the Austell-Frolona antiform, west-central Georgia, IN Wigley, P.B., ed., Latest thinking on the stratigraphy of selected areas in Georgia; Volume 1: Georgia Geologic Survey Information Circular, no. 54-A, p. 55-67.


Summary:

The Villa Rica Gneiss Member of the Mud Creek Formation of the New Georgia Group is here named in the Villa Rica antiform on the northwest flank of the Austell-Frolona antiform in west-central GA. It consists of biotite-quartz-plagioclase gneiss with minor muscovite and epidote and is interpreted to be a felsic metavolcanic metadacite. Interlayered with the Cedar Lake Quartzite Member of the Mud Creek. Grades into stratigraphically overlying Andy Mountain and Bill Arp Formations of the informal Roosterville group. Age is Proterozoic(?).

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Villa Rica Gneiss*
  • Modifications:
    • Revised
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Higgins, M.W., Atkins, R.L., Crawford, T.J., Crawford, R.F., III, Brooks, Rebekah, and Cook, R.B., Jr., 1988, The structure, stratigraphy, tectonostratigraphy, and evolution of the southernmost part of the Appalachian Orogen, Georgia and Alabama: U.S. Geological Survey Professional Paper, 1475, 173 p., (incl. geologic map, scale 1:500,000)


Summary:

The Villa Rica Gneiss Member of the Mud Creek Formation of Abrams and McConnell (1981), is here revised as the Villa Rica Gneiss and approved for use by the USGS. It is a trondhjemite body in the Ropes Creek thrust sheet in western GA. Age is mostly Cambrian.

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Villa Rica Gneiss*
  • Modifications:
    • Age modified
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Crawford, T.J., Higgins, M.W., Crawford, R.F., Atkins, R.L., Medlin, J.H., and Stern, T.W., 1999, Revision of stratigraphic nomenclature in the Atlanta, Athens, and Cartersville 30' x 60' quadrangles, Georgia: Georgia Geologic Survey Bulletin, no. 130, 45 p.


Summary:

Age of Villa Rica Gneiss of the allochthonous assemblage is changed to Late Proterozoic(?) to Middle Ordovician(?) based on a more conservative theory that the allochthonous rocks are 1) probably not older than Late Proterozoic because they are not part of Middle Proterozoic (Grenvillian) basement and 2) they could be as young, but not younger than, the time marking the beginning of closure of the ocean they originated in, as set by the slope reversal marked by deposition of Middle Ordovician Rockmart Slate upon unconformity at top of Upper Cambrian to Middle(?) Ordovician Knox Group and Middle Ordovician Lenoir Limestone.

Source: GNU records (USGS DDS-6; Reston GNULEX).


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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 ([ ]).