Skip to main content

Geologic units in Fannin county, Georgia

Additional scientific data in this geographic area

Mica Schist (Precambrian-Paleozoic) at surface, covers 29 % of this area

Mica Schist

Lithology: mica schist

Slate/ Quartzite/ Conglomerate (Precambrian-Paleozoic) at surface, covers 24 % of this area

Slate/ Quartzite/ Conglomerate

Cross-Biotite Schist (Precambrian-Paleozoic) at surface, covers 13 % of this area

Cross-Biotite Schist

Lithology: biotite schist

Metagraywacke/ Mica Schist/ Calc-silicate Gneiss (Precambrian-Paleozoic) at surface, covers 10 % of this area

Metagraywacke/ Mica Schist/ Calc-silicate Gneiss

Graphitic Phyllite (Precambrian-Paleozoic) at surface, covers 8 % of this area

Graphitic Phyllite

Lithology: phyllite

Aluminous Schist (Precambrian-Paleozoic) at surface, covers 5 % of this area

Aluminous Schist

Lithology: schist

Metagraywacke undifferentiated (Precambrian-Paleozoic) at surface, covers 2 % of this area

Metagraywacke undifferentiated

Quartzite (Precambrian-Paleozoic) at surface, covers 2 % of this area

Quartzite

Lithology: quartzite

Amphibolite (Precambrian-Paleozoic) at surface, covers 1 % of this area

Amphibolite

Lithology: amphibolite

Conglomerate (Precambrian-Paleozoic) at surface, covers 0.9 % of this area

Conglomerate

Lithology: conglomerate

Phyllite and Quartzite (Precambrian-Paleozoic) at surface, covers 0.7 % of this area

Phyllite and Quartzite

Lithology: phyllite; quartzite

Great Smoky Group, including Anakeesta Formation, Thunderhead Sandstone, and Elkmont Sandstone (Precambrian) at surface, covers 0.4 % of this area

Great Smoky Group - Characterized by very massive layers of coarse graywacke and arkose. The formations have been mapped only in the region of the Great Smoky Mountains. Near Ducktown, in ascending order, the Copperhill, Hughes Gap, Hothouse, and Dean Formations are recognized. Thickness 14,000 to about 40,000 feet. Includes Anakeesta Formation - Dark-gray, bluish-gray, and black slate with dark-gray interbeds of fine-grained sandstone. Thickness 3,000 to 4,500 feet; Thunderhead Sandstone - Coarse, gray feldspathic sandstone, graywacke, and conglomerate; occurs in massive ledges; graded bedding and blue quartz characteristic. Thickness 5,500 to 6,300 feet; Elkmont Sandstone - Coarse to fine, gray feldspathic sandstone, graywacke, and fine conglomerate; generally finer grained beds in lower part; graded bedding typical. Thickness 1,000 to 8,000 feet

Walden Creek Group, including Sandsuck Formation, Wilhite Formation, Shields Formation, and Licklog Formation (Cambrian) at surface, covers 0.3 % of this area

Walden Creek Group - The formations, other than the Sandsuck, are applicable mainly in the region of the Great Smoky Mountains. Thickness about 8,000 feet, Includes Sandsuck Formation - Olive-green and gray, argillaceous, micaceous shale with coarse feldspathic sandstone and quartz- pebble conglomerate. Thickness about 2,000 feet; Wilhite Formation - Gray to green siltstone and slate with interbeds of pebble conglomerate, sandstone, and quartzite. Thickness about 4,000 feet; Shields Formation - Massive conglomerate, sandstone, argillaceous slate; conglomerate (pebbles of various rock types) characteristic. Thickness about 1,500 feet.; Licklog Formation - Feldspathic sandstone, greenish phyllite, and bluish-gray slate. Thickness about 1,500 feet.

Ocoee Supergroup, Great Smokey Group; Metasandstone, Metagraywacke, Metasiltstone, and Mica Schist (Late Proterozoic) at surface, covers 0.2 % of this area

Metasandstone, Metagraywacke, Metasiltstone, and Mica Schist - 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.

Biotite Gneiss (Precambrian-Paleozoic) at surface, covers 0.1 % of this area

Biotite gneiss

Lithology: biotite gneiss

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

Mineral Bluff Formation - quartz-chlorite-sericite schist and phyllite with thin quartzite layers and minor interbedded graphitic schist, garnet-mica schist, staurolite schist, cross-biotite schist, and dark slate.

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

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

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

Brasstown Formation - cross-biotite schist; includes micaceous quartzite in lower part.

Lithology: mica schist; quartzite

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

Mica Schist/ Gneiss

Lithology: mica schist; gneiss

Murphy Marble, Andrews Formation, and Nottely Quartzite, undivided (Late Proterozoic) at surface, covers < 0.1 % of this area

Murphy Marble, Andrews Formation, and Nottely Quartzite, undivided - Murphy Marble: calcareous to dolomitic; Andrews Formation: calcareous cross-biotite schist; Nottely Quartzite: meta-orthoquartzite with slate.

Lithology: marble; schist; quartzite; slate

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

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

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

Copperhill Formation - metagraywacke, massive, graded bedding common; includes dark-gray slate, mica schist, and nodular calc-silicate rock.