Garnet-Graphite Paragneiss

Light-brown-weathering, medium- to fine-grained graphite-biotite-garnet-plagioclase quartz paragneiss; includes quartz-chlorite-magnetite schist and carbonaceous phyllonite; graphite makes up 10 percent of the rock in places and garnet, up to 25 percent locally. The protolith of this unit is intepreted to be metasedimentary country rock that Grenville-age plutonic rocks intruded. The rock is similar in appearance to parts of the border gneiss (Ybr).
State Virginia
Name Garnet-Graphite Paragneiss
Geologic age Proterozoic Y
Lithologic constituents
Major
Metamorphic > Metasedimentary > Paragneiss
Comments Blue Ridge Basement Complex, Middle Proterozoic (Early or Pre-Grenville-Age) Gneisses
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 Fauquier - Loudoun