Geologic units in Watauga county, North Carolina

Additional scientific data in this geographic area

Biotite Granitic Gneiss (Middle Proterozoic) at surface, covers 30 % of this area

Unconformity; contains paragneiss and granitic to quartz monzonitic orthogneiss; locally schistose and mylonitic. Locally includes tectonic slices, infolded remnants, or recrystallized equivalents of the Grandfather Mountain Formation. Equivalent to the Wilson Creek Gneiss.

Ashe Metamorphic Suite and Tallulah Falls Formation; Amphibolite (Late Proterozoic) at surface, covers 14 % of this area

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

Alligator Back Formation; Gneiss (Late Proterozoic) at surface, covers 10 % of this area

Finely laminated to thin layered; locally contains massive gneiss and micaceous granule conglomerate; includes schist, phyllite, and amphibolite.

Granodioritic Gneiss (Middle Proterozoic) at surface, covers 10 % of this area

Unconformity; greenish gray to pinkish gray, porphyroclastic to mylonitic; epidote, sericite, and chlorite common.

Ashe Metamorphic Suite and Tallulah Falls Formation; Muscovite-biotite gneiss (Late Proterozoic) at surface, covers 8 % of this area

Locally sulfidic; interlayered and gradational with mica schist, minor amphibolite, and hornblende gneiss.

Grandfather Mountain Formation; Metasiltstone (Late Proterozoic) at surface, covers 6 % of this area

Locally contains thin bedded iron-bearing dolomitic marble; interlayered with phyllite, metagraywacke, and meta-arkose.

Blowing Rock Gneiss (Middle Proterozoic) at surface, covers 4 % of this area

Unconformity; abundant white potassic feldspar megacrysts in finely banded biotite schist, locally calcareous; interlayered with quartz-feldspar schist, calcareous biotite schist, phyllite, black slate, calcareous quartzite, sulfidic greenstone, and siliceous tuff.

Metamorphosed Granitic Rock (Late Proterozoic) at surface, covers 4 % of this area

Massive to foliated, locally mylonitic. Beech, Crossnore, Brown Mountain, Lansing, and other granitic rocks.

Grandfather Mountain Formation; Metagraywacke (Late Proterozoic) at surface, covers 4 % of this area

Cross-bedding and graded bedding common, locally conglomeratic; interlayered with metasiltstone and phyllite.

Grandfather Mountain Formation; Greenstone (Late Proterozoic) at surface, covers 2 % of this area

Schistose to massive, amygdaloidal; interlayered with metasedimentary rocks. Includes Montezuma Member (metabasalt) in upper part.

Grandfather Mountain Formation; Meta-arkose (Late Proterozoic) at surface, covers 2 % of this area

Sericitic, conglomeratic, locally cross-bedded; interlayered metasiltstone and slate.

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

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.

Chilhowee Group; Lower Chilhowee (Cambrian) at surface, covers 1 % of this area

Feldspathic arenite, white to yellowish gray. Minor silty shale, feldspathic siltstone, and conglomerate in lower part. Includes Unicoi Formation of Hot Springs window.

Grandfather Mountain Formation; Felsic metavolcanic rocks and metasedimentary rocks (Late Proterozoic) at surface, covers 0.9 % of this area

Tentatively correlated with Grandfather Mountain Formation.

Linville Metadiabase (Late Proterozoic) at surface, covers 0.4 % of this area

Metadiabase, greenstone, and amphibolite dikes and sills; massive to schistose.

Alligator Back Formation; Amphibolite (Late Proterozoic) at surface, covers 0.3 % of this area

Equigranular, massive to well foliated, interlayered, rarely discordant, metamorphosed intrusive and extrusive mafic rock; may include metasedimentary rock.

Grandfather Mountain Formation; Porphyritic felsic volcanic rock (Late Proterozoic) at surface, covers 0.2 % of this area

Phyllitic to schistose, contains euhedral to subhedral phenocrysts of gray quartz and pink potassic feldspar. Resembles quartzite and meta-arkose.

Cranberry Granite (Precambrian) at surface, covers 0.1 % of this area

Complex of intertonguing rock types including migmatite, granitic gneisses, monzonite, quartz diorite, greenstone, mica and hornblende schists, abundant granitic pegmatite.