Old Rag Granite

Old Rag granite (Furcron, 1934). Leucocratic, coarse grained, foliated, alkali feldspar-blue quartz granite contains accessory biotite, muscovite, garnet, magnetite, and zircon; dated at 1115 Ma (U-Pb zircon; Lukert, 1982). Geophysical signature: positive radiometric anomaly.
State Virginia
Name Old Rag Granite
Geologic age Proterozoic Y
Lithologic constituents
Major
Igneous > Plutonic > Granitic > Granite
Comments Blue Ridge Basement Complex, Middle Proterozoic (Grenville-Age) Plutonic Rocks
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 Madison