Layered Quartzofeldspathic Augen Gneiss and Flaser Gneiss

Leucocratic to mesocratic, mesoscopically-layered coarse-grained quartzofeldspathic biotite gneiss contains prominent polycrystalline quartz-feldspar augen within an anastomosing, mica-rich, schistose matrix. Major mineralogy includes quartz, plagioclase, microcline, muscovite, biotite, epidote, titanite, and ilmenite; apatite and zircon are accessory minerals. This unit is gradational into biotite granulite and gneiss (Ygb), and is at least in part derived from that unit by superimposition of cataclastic to mylonitic fabric. Includes in part Stage Road layered gneiss (Sinha and Bartholomew, 1984; U-Pb discordia from 915 Ma to 1860 Ma).
State Virginia
Name Layered Quartzofeldspathic Augen Gneiss and Flaser Gneiss
Geologic age Proterozoic Y
Lithologic constituents
Major
Metamorphic > Gneiss > Biotite-gneissfelsic gneiss and flaser gneiss
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 Amherst - Bedford - Floyd - Franklin - Nelson - Bedford - Lynchburg