Geologic units in Union county, Georgia

Additional scientific data in this geographic area

Biotite Gneiss (Precambrian-Paleozoic) at surface, covers 49 % of this area

Biotite gneiss

Mica Schist/ Gneiss (Precambrian-Paleozoic) at surface, covers 24 % of this area

Mica Schist/ Gneiss

Aluminous Schist (Precambrian-Paleozoic) at surface, covers 15 % of this area

Aluminous Schist

Garnet Mica Schist (Precambrian-Paleozoic) at surface, covers 6 % of this area

Garnet Mica Schist

Cross-Biotite Schist (Precambrian-Paleozoic) at surface, covers 3 % of this area

Cross-Biotite Schist

Amphibolite/ Ultramafic (Precambrian-Paleozoic) at surface, covers 2 % of this area

Amphibolite/ Ultramafic

Ultramafic rocks undifferentiated (Precambrian-Paleozoic) at surface, covers 0.2 % of this area

Ultramafic rocks undifferentiated

Graphitic Phyllite (Precambrian-Paleozoic) at surface, covers 0.1 % of this area

Graphitic Phyllite

Ocoee Supergroup, Great Smokey Group; Metasandstone, Metagraywacke, Metasiltstone, and Mica Schist (Late Proterozoic) at surface, covers < 0.1 % of this area

Beds and lenses of calc-silicate rock locally abundant; garnet, staurolite, and cross-biotite porphyroblasts common in fine-grained layers. Includes Hughes Gap and Hothouse formations in southern area; Horse Branch Member of Ammons Formation and Grassy Branch Formation in northern area.

Metagraywacke/ Mica Schist-Quartzite/ Amphibolite (Precambrian-Paleozoic) at surface, covers < 0.1 % of this area

Metagraywacke/ Mica Schist-Quartzite/ Amphibolite

Ocoee Supergroup, Great Smokey Group; Dean Formation (Late Proterozoic) at surface, covers < 0.1 % of this area

Sericite schist with cross-biotite, staurolite, and garnet porphyroblasts; interbedded metagraywacke and quartz-pebble metaconglomerate.

Nantahala Formation and Tusquitee Quartzite, undivided (Late Proterozoic) at surface, covers < 0.1 % of this area

Nantahala Formation: slate and metasiltstone, dark gray, laminated to thin bedded, sulfidic; Tusquitee Quartzite: white to light yellowish gray, numerous, thin slate layers.

Brasstown Formation (Late Proterozoic) at surface, covers < 0.1 % of this area

Cross-biotite schist; includes micaceous quartzite in lower part.