USGS Home
Contact USGS
Search USGS

Mineral Resources > Online Spatial Data > Geology > by state > North Carolina Geology

Geologic units in Macon county, North Carolina

[Additional scientific data in this geographic area]

Coweeta Group; Biotite Gneiss (Middle/Late Proterozoic) at surface, covers 44 % of this area

Biotite Gneiss - migmatitic; interlayered and gradational with biotite-garnet gneiss and amphibolite; locally abundant quartz and alumino-silicates. Stratigraphic position uncertain.

Lithology: biotite gneiss; amphibolite

Ocoee Supergroup, Great Smokey Group; Dean Formation (Late Proterozoic) at surface, covers 1 % of this area

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

Lithology: mica schist; metasedimentary rock

Ashe Metamorphic Suite and Tallulah Falls Formation; Biotite gneiss (Late Proterozoic) at surface, covers 11 % of this area

Biotite gneiss - interlayered with biotite-garnet gneiss, biotite-muscovite schist, garnet-mica schist, and amphibolite.

Lithology: biotite gneiss; mica schist; amphibolite

Coweeta Group (Late Proterozoic) at surface, covers 5 % of this area

Coweeta Group - quartz dioritic gneiss, feldspar-quartz-biotite gneiss, metasandstone and quartzite, alumino-silicate schist, garnetiferous biotite gneiss, and minor amphibolite. Quartz dioritic gneiss predominant.

Lithology: gneiss; metasedimentary rock; quartzite; schist; amphibolite

Quartz Diorite to Granodiorite (Devonian) at surface, covers 3 % of this area

Quartz Diorite to Granodiorite (390 my) - contains biotite, muscovite, and xenocrysts. Includes Whiteside Mountain, Stone Mountain, Mount Airy, Spruce Pine, and other smaller plutons.

Lithology: quartz diorite; granodiorite

Mineral Bluff Formation (Late Proterozoic) at surface, covers 0.2 % 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.

Lithology: schist; phyllite; quartzite; slate

Rabun Gneiss (Ordovician) at surface, covers 4 % of this area

Rabun Gneiss (450-500 my) - weakly to well foliated, granitic to quartz monzonitic.

Lithology: granitic 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

Ocoee Supergroup, Great Smokey Group; Copperhill Formation (Late Proterozoic) at surface, covers 2 % of this area

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

Lithology: metasedimentary rock; slate; mica schist; calc-silicate rock

Ocoee Supergroup, Great Smokey Group; Metasandstone, Metagraywacke, Metasiltstone, and Mica Schist (Late Proterozoic) at surface, covers 7 % 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.

Lithology: metasedimentary rock; mica schist; calc-silicate rock

Nantahala Formation and Tusquitee Quartzite, undivided (Late Proterozoic) at surface, covers 0.5 % 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.

Lithology: slate; metasedimentary rock; quartzite

Ocoee Supergroup; Great Smokey Group, undivided (Late Proterozoic) at surface, covers 5 % of this area

Great Smokey Group, undivided - thick metasedimentary sequence of massive to graded beds of metagraywacke and metasiltstone with interbedded graphitic and sulfidic slate and schist.

Lithology: metasedimentary rock; slate; schist

Ashe Metamorphic Suite and Tallulah Falls Formation; Amphibolite (Late Proterozoic) at surface, covers 0.5 % of this area

Amphibolite - equigranular, massive to well foliated, interlayered, rarely discordant, metamorphosed intrusive to extrusive mafic rock; may include metasedimentary rock.

Lithology: amphibolite; metasedimentary rock

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

Biotite Granitic Gneiss (Middle Proterozoic) at surface, covers 1 % of this area

Biotite Granitic Gneiss - unconformity; pinkish gray to light gray, massive to well-foliated, granitic to quartz monzonitic; includes variably mylonitized orthogneiss and paragneiss, interlayered amphibolite, calc-silicate rock, and marble. Includes granites of the Bryson City area, Straight Fork window, and Elk Park Plutonic Suite.

Lithology: granitic gneiss; amphibolite; calc-silicate rock; marble

Ocoee Supergroup, Great Smokey Group; Wehutty Formation (Late Proterozoic) at surface, covers 4 % of this area

Wehutty Formation - slate to schist, dark gray, graphitic and sulfidic; includes mica schist, metagraywacke, and metaconglomerate.

Lithology: slate; schist; metasedimentary rock

Coweeta Group; Amphibolite (Middle/Late Proterozoic) at surface, covers 3 % of this area

Amphibolite - equigranular, massive to well foliated, interlayered, rarely discordant, metamorphosed intrusive to extrusive mafic rock; may include metasedimentary rock.

Lithology: amphibolite; metasedimentary rock

Ashe Metamorphic Suite and Tallulah Falls Formation; Muscovite-biotite gneiss (Late Proterozoic) at surface, covers 9 % of this area

Muscovite-biotite gneiss - locally sulfidic; interlayered and gradational with mica schist, minor amphibolite, and hornblende gneiss.

Lithology: gneiss; mica schist; amphibolite

Meta-ultramafic Rock (Paleozoic/Late Proterozoic) at surface, covers 0.2 % of this area

Meta-ultramafic Rock - metamorphosed dunite and peridotite; serpentine, soapstone, and other altered ultramafic rock. Only larger bodies shown.

Lithology: metamorphic rock; serpentinite