Ashe Formation - Amphibolite

Dark-greenish-gray to black, coarse to fine-grained amphibolite, hornblende gneiss, and schist, with interlayered biotite-muscovite gneiss and mica schist. Coarse garnetiferous amphibolite, pink and white marble, and pyrite-chalcopyrite-calcite veins are common near the top of the Ashe. Mineralogy: (1) quartz + actinolite + epidote + chlorite; (2) quartz + hornblende + plagioclase + epidote + garnet + magnetite. Geophysical signature: amphibolite, and hornblende gneiss and schist give positive linear magnetic anomalies. Relict amygdaloidal textures and hyaloclastic (pillow) structures indicate massive to thick-bedded amphibolite and hornblende gneiss were derived from basaltic flows or shallow sills. Some thin-bedded hornblende gneiss and schist units that commonly contain interbedded micaceous and feldspathic layers may be derived from volcaniclastic sedimentary rocks.
State Virginia
Name Ashe Formation - Amphibolite
Geologic age Proterozoic Z
Lithologic constituents
Major
Metamorphic > Amphibolite
Comments Lynchburg Group; Blue Ridge Anticlinorium (Southwest)
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 Carroll - Floyd - Franklin - Grayson - Patrick - Galax