Geologic units in Henderson county, North Carolina

Henderson Gneiss (Cambrian) at surface, covers 44 % of this area

Monzonitic to granodioritic; inequigranular.

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

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

Garnet-Mica Schist (Cambrian/Late Proterozoic) at surface, covers 12 % of this area

Interlayered with amphibolite.

Granite Gneiss (Silurian/Ordovician) at surface, covers 11 % of this area

Poorly foliated; interlayered with biotite augen gneiss.

Porphyroblastic Gneiss (Cambrian/Late Proterozoic) at surface, covers 6 % of this area

Massive to foliated, granodioritic, migmatitic.

Caesars Head Granite Gneiss (Devonian/Silurian) at surface, covers 6 % of this area

Equigranular to porphyritic, massive to well foliated; contains biotite and muscovite.

Rocks of Brevard Fault Zone (Uncertain, possibly Permian or Devonian) at surface, covers 3 % of this area

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

Ashe Metamorphic Suite and Tallulah Falls Formation; Metagraywacke (Late Proterozoic) at surface, covers 2 % of this area

Foliated to massive, locally conglomeratic; interlayered and gradational with mica schist, muscovite-biotite gneiss, and rare graphitic schist.

Amphibolite and Biotite Gneiss (Cambrian/Late Proterozoic) at surface, covers 0.9 % of this area

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

Migmatitic Granitic Gneiss (Ordovician/Cambrian) at surface, covers 0.5 % of this area

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

Biotite Gneiss and Schist (Cambrian/Late Proterozoic) at surface, covers < 0.1 % 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.

Migmatitic granitoid gneiss (Ordovician) at surface, covers < 0.1 % of this area

Variably foliated, variably migmatitic, and granitic to quartz dioritic in composition

Quartz Diorite to Granodiorite (Devonian) at surface, covers < 0.1 % of this area

Contains biotite, muscovite, and xenocrysts. Includes Whiteside Mountain, Stone Mountain, Mount Airy, Spruce Pine, and other smaller plutons.

Garnetiferous mica schist (Cambrian or Neoproterozoic) at surface, covers < 0.1 % of this area

Aluminous muscovite-biotite schist, locally having subordinate amphibolite layers

Megacrystic biotite gneiss (Cambrian or Neoproterozoic) at surface, covers < 0.1 % of this area

Variably layered biotite-quartz-feldspar gneiss having porphyroclasts and/or porphyroblasts of plagioclase and locally of quartz and potassium feldspar

Caesars Head Granite (Ordovician to Silurian) at surface, covers < 0.1 % of this area

Well foliated, banded to non-banded biotite granitoid gneiss or gneissic granitoid; cuts Seneca thrust fault