Geologic units in Burke county, North Carolina

Additional scientific data in this geographic area

Biotite Gneiss and Schist (Cambrian/Late Proterozoic) at surface, covers 27 % of this area

Inequigranular, locally abundant potassic feldspar and garnet; interlayered and gradational with calc-silicate rock, sillimanite-mica schist, mica schist, and amphibolite. Contains small masses of granitic rock.

Mica Schist (Cambrian/Late Proterozoic) at surface, covers 24 % of this area

Garnet, staurolite, kyanite, or sillimanite occur locally; lenses and layers of quartz schist, micaceous quartzite, calc-silicate rock, biotite gneiss, amphibolite, and phyllite.

Migmatitic Granitic Gneiss (Ordovician/Cambrian) at surface, covers 14 % of this area

Foliated to massive, granitic to quartz dioritic; biotite gneiss and amphibolite common.

Biotite Granitic Gneiss (Middle Proterozoic) at surface, covers 9 % 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.

Metamorphosed Granitic Rock (Ordovician/Cambrian) at surface, covers 7 % of this area

Equigranular to megacrystic, foliated to massive. Includes Toluca Granite.

Chilhowee Group; Lower Chilhowee (Cambrian) at surface, covers 3 % of this area

Feldspathic quartzite, white to yellowish gray. Minor silty slate, feldspathic metasiltstone, and metaconglomerate in lower part.

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

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

Henderson Gneiss (Cambrian) at surface, covers 2 % of this area

Monzonitic to granodioritic; inequigranular.

Alligator Back Formation; Gneiss (Late Proterozoic) at surface, covers 2 % of this area

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

Megacrystic Biotite Gneiss (Cambrian/Late Proterozoic) at surface, covers 2 % of this area

Poorly layered to massive; megacrysts of microcline and quartz; local mica schist, amphibolite, and biotite gneiss

Amphibolite and Biotite Gneiss (Cambrian/Late Proterozoic) at surface, covers 2 % of this area

Interlayered; minor layers and lenses of hornblende gneiss, metagabbro, mica schist, and granitic rock.

Inequigranular Biotite Gneiss (Cambrian/Late Proterozoic) at surface, covers 2 % of this area

Weakly foliated to massive, contains plagioclase megacrysts and, rarely, larger megacrysts of quartz and feldspar.

Rocks of Brevard Fault Zone (Uncertain, possibly Permian or Devonian) at surface, covers 1 % of this area

"Fish scale" schist and phyllonite, graphitic; interlayered with feldspathic metasandstone, marble lenses.

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

Vitreous quartzite, white to light gray; interbedded sandy metasiltstone and slate.

Metamorphosed Granite (Late Proterozoic) at surface, covers 1.0 % of this area

Massive to foliated, locally mylonitic. Equivalent to Brown Mountain Granite.

Grandfather Mountain Formation; Meta-arkose (Late Proterozoic) at surface, covers 0.4 % of this area

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

Meta-ultramafic Rock (Paleozoic/Late Proterozoic) at surface, covers < 0.1 % of this area

Metamorphosed dunite, local peridotite, serpentinite, soapstone, and other ultramafic rock. Only larger bodies shown.

Grandfather Mountain Formation; Porphyritic felsic volcanic rock (Late Proterozoic) at surface, covers < 0.1 % of this area

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

Grandfather Mountain Formation; Greenstone (Late Proterozoic) at surface, covers < 0.1 % of this area

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

Linville Metadiabase (Late Proterozoic) at surface, covers < 0.1 % of this area

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

Grandfather Mountain Formation; Felsic metavolcanic rocks and metasedimentary rocks (Late Proterozoic) at surface, covers < 0.1 % of this area

Tentatively correlated with Grandfather Mountain Formation.

Grandfather Mountain Formation; Metasiltstone (Late Proterozoic) at surface, covers < 0.1 % 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 < 0.1 % 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.