Biotite Granite Gneiss

Light-gray, medium-grained, equigranular, broadly-layered, locally migmatitic. Mineralogy: quartz + plagioclase + microcline + biotite + muscovite + hornblende; apatite and zircon are accessory minerals. Geophysical signature: diffuse pattern of positive radiometric anomalies.
State Virginia
Name Biotite Granite Gneiss
Geologic age Proterozoic
Lithologic constituents
Major
Metamorphic > Gneiss > Biotite-gneissbiotite granite gneiss
Comments Central Piedmont
References

Virginia Division of Mineral Resources, 1993, Geologic Map of Virginia: Virginia Division of Mineral Resources, scale 1:500,000.

Virginia Division of Mineral Resources, 2003, Digital Representation of the 1993 Geologic Map of Virginia, Publication 174, CD ROM (ISO-9660) contains image file, expanded explanation in pdf, and ESRI shapefiles, scale 1:500,000.

NGMDB product
Counties Amelia - Cumberland - Nottoway - Prince Edward