Megacrystic Charnockite

Porphyritic, foliated pyroxene-hornblende granite contains potassium feldspar megacrysts up to 4 cm across; hornblende and magnetite-ilmenite are the dominant ferromagnesian minerals; color index is about 15. Pyroxene is thoroughly uralitized; plagioclase contains abundant small epidote prisms. Adjacent to contacts with overlying Cambrian clastic rocks, charnockite grades into unakite; includes Vesuvius megaporphyry of Bartholomew and Lewis (1984).
State Virginia
Name Megacrystic Charnockite
Geologic age Proterozoic Y
Lithologic constituents
Igneous > Plutonic > Charnockite
Comments Blue Ridge Basement Complex, Middle Proterozoic (Grenville-Age) Plutonic Rocks

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 Nelson - Rockbridge