Summary of Citation

GEOLEX database

Geologic Unit: Oak Grove

Publication:
German, J.M., 1988, The geology of gold occurrences in the 
   west-central Georgia Piedmont: Georgia Geological Survey 
   Bulletin, no. 107, 48 p.

Usage in Publication:
Oak Grove Gneiss

Modifications:	Geologic Province:	Dominant Lithology:
Named	Piedmont-Blue Ridge province	Gneiss

Summary:
Rock unit in Carroll County, GA, is herein named the Oak Grove Gneiss for exposures along Hwy 27 in community of Oak Grove. Unit is described as leucocratic, medium- to coarse-grained, blastoporphyritic biotite-muscovite-plagioclase-quartz-microcline orthogneiss. Microcline megacrysts up to 2 cm are common. Intrudes the Bill Arp Formation at the type locality; elsewhere intrudes the Dog River and Andy Mountain Formations, all of Sandy Springs Group. Is probably a pre- to synmetamorphic pluton and is very similar mineralogically and texturally to the Austell and Sand Hill Gneisses. All three may have been derived from a common parent magma. No dimensions given for the pluton, but geologic map reveals the intrusion to be 1 to 2 km wide and greater than 6 km long.
Source: GNU records (USGS DDS-6; Reston GNULEX).