Ashe Formation

Ashe Formation (Sauratown Mountains; Conley, 1985). Light-gray, medium-grained muscovite and muscovite biotite gneiss with thick interbeds of muscovite schist and pebbly feldspathic quartzite. Thick lenses of garnet- hornblende schist locally mark the basal and upper contacts with the underlying basement gneiss and the overlying metapelites respectively. The unit is cut by dikes, sills and thick sheets of pegmatite and alaskite, especially concentrated along the zone of transitional contact with Alligator Back mica schist units. Mineralogy: (1) quartz + plagioclase + Potassium feldspar + muscovite + biotite + tourmaline + epidote + titanite+ magnetite-ilmenite; (2) quartz + plagioclase + muscovite+ biotite + graphite + magnetite-ilmenite; (3) hornblende + plagioclase + quartz + garnet; (4) hornblende + plagioclase + quartz + epidote + chlorite + magnetite-ilmenite. Geophysical signature: Low-amplitude, elongate, positive magnetic anomalies are associated with garnet-mica and hornblende schist outcrop belts; elongate magnetic lows coincide with areas underlain by gneiss units.
State Virginia
Name Ashe Formation
Geologic age Proterozoic Z
Lithologic constituents
Major
Metamorphic > Gneiss > Biotite-gneiss
Minor
Metamorphic > Metasedimentary > Metaclastic > Quartzite
Metamorphic > Amphibolite
Comments Western Piedmont (Sauratown Mountains)
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 Henry - Pittsylvania