Biotite Granodiorite and Biotite Granite

Leucocratic to mesocratic, medium-grained, equigranular, vaguely foliated, epidote-, garnet-, fluorite- and/or allanite-bearing, two-feldspar muscovite-biotite granodiorite to granite; salt-and-pepper appearance is characteristic; associated aplite and pegmatite dikes common. Geophysical signature: weak positive radiometric anomaly. The plutons of this suite are widespread in the southeastern portion of the basement complex, and are correlated with Rockfish River, Mobley Mountain, Striped Rock plutons, and with Robertson River Igneous Suite.
State Virginia
Name Biotite Granodiorite and Biotite Granite
Geologic age Proterozoic Z
Lithologic constituents
Major
Igneous > Plutonic > Granitic > Granite
Igneous > Plutonic > Granitic > Granodiorite
Incidental
Igneous > Plutonic > Granitic > Leucocratic-granitic > Pegmatite (Dike or sill)
Igneous > Plutonic > Granitic > Leucocratic-granitic > Aplite (Dike or sill)
Comments Blue Ridge Basement Complex, Late Proterozoic Igneous
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 Albemarle - Amherst - Bedford - Franklin - Nelson - Roanoke - Rockbridge