USGS Home
Contact USGS
Search USGS

Mineral Resources > Online Spatial Data > Geology > by state > Virginia Geology

Geologic units in Floyd county, Virginia

[Additional scientific data in this geographic area]

Ashe Formation - Biotite gneiss (Proterozoic Z) at surface, covers 55 % of this area

Ashe Formation - Biotite gneiss.

Lithology: biotite gneiss

Ashe Formation -Mica schist or phyllite (Proterozoic Z) at surface, covers 7 % of this area

Ashe Formation - Mica schist or phyllite

Lithology: mica schist; phyllite

Leucocratic Granulite and Gneiss (Proterozoic Y) at surface, covers 2 % of this area

Leucocratic granulite and gneiss.

Lithology: granulite; gneiss

Porphyritic Leucocharnockite (Proterozoic Y) at surface, covers 0.2 % of this area

Porphyritic Leucocharnockite - Leucocharnockite

Lithology: granite

Alligator Back Formation - Actinolite schist (Proterozoic Z-Cambrian) at surface, covers 1 % of this area

Alligator Back Formation - Actinolite schist

Lithology: schist

Rome Formation (Cambrian) at surface, covers < 0.1 % of this area

Rome Formation - Dusky-red and green shale and siltstone, dolomite, and limestone.

Lithology: shale; siltstone; sandstone; dolostone (dolomite); limestone

Chilhowee Group (Cambrian) at surface, covers 0.6 % of this area

Chilhowee Group - Appalachian Plateaus and Valley and Ridge: Quartzite, conglomerate, feldspathic sandstone, phyllite, and minor ferruginous sandstone and volcanic rocks. Blue Ridge Anticlinorium: Conglomerate, quartzite, metasiltstone, and phyllite.

Lithology: quartzite; conglomerate; sandstone; phyllite; meta-argillite; volcanic rock (aphanitic)

Shady Dolomite (Cambrian) at surface, covers < 0.1 % of this area

Shady Dolomite - Dolomite.

Lithology: dolostone (dolomite); limestone; shale

Ultramafic Rocks (Proterozoic Z-Cambrian) at surface, covers 0.2 % of this area

Ultramafic rocks

Lithology: ultramafic rock; schist

Unicoi Formation (Cambrian) at surface, covers < 0.1 % of this area

Unicoi Formation - Sandstone and quartzite with phyllite, tuffaceous phyllite, conglomerate, and minor basalt.

Lithology: sandstone; quartzite; phyllite; conglomerate; basalt

Charnockite (Proterozoic Y) at surface, covers 1 % of this area

Charnockite.

Lithology: granitic gneiss

Layered Biotite Granulite and Gneiss (Proterozoic Y) at surface, covers 7 % of this area

Layered biotite granulite and gneiss.

Lithology: gneiss; granulite

Alligator Back Formation - Feldspathic metagraywacke (Proterozoic Z-Cambrian) at surface, covers 3 % of this area

Alligator Back Formation - Meta-argillite is feldspathic metagraywacke; graphitic mica schist, and quartzite.

Lithology: meta-argillite; schist; quartzite; melange; marble; gneiss

Porphyoblastic Biotite-Plagioclase Augen Gneiss (Proterozoic Y) at surface, covers 8 % of this area

Porphyoblastic biotite-plagioclase augen gneiss

Lithology: augen gneiss

Layered Porphyrobliastic Pyroxene Granulite (Proterozoic Y) at surface, covers 0.9 % of this area

Layered porphyroblastic pyroxene granulite

Lithology: granulite

Layered Quartzofeldspathic Augen Gneiss and Flaser Gneiss (Proterozoic Y) at surface, covers 2 % of this area

Layered quartzofeldspathic augen gneiss and flaser gneiss.

Lithology: felsic gneiss; flaser gneiss

Erwin and Hampton Formations (Cambrian) at surface, covers 0.9 % of this area

Erwin and Hampton Formations - Sandstone, quartzite, and shale.

Lithology: sandstone; quartzite; shale

Ashe Formation- Amphibolite (Proterozoic Z) at surface, covers 10 % of this area

Ashe Formation - Amphibolite and garnet amphibolite

Lithology: amphibolite