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

Geologic units in Transylvania county, North Carolina

[Additional scientific data in this geographic area]

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

Granite gneiss: equigranular to inequigranular granite gneiss and augen gneiss, undivided

Lithology: granitic gneiss

Toxaway Gneiss (Middle Proterozoic) at surface, covers 8 % of this area

Toxaway Gneiss (1203 my) - unconformity; poorly foliated to well-foliated; equigranular to inequigranular, granitic.

Lithology: granitic gneiss

Henderson Gneiss (Cambrian) at surface, covers 28 % of this area

Henderson Gneiss (524 my) - monzonitic to granodioritic; inequigranular.

Lithology: gneiss

Ashe Metamorphic Suite and Tallulah Falls Formation; Amphibolite (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

Henderson Gneiss (Cambrian) at surface, covers < 0.1 % of this area

Henderson Gneiss: biotite granitoid augen gneiss having distinctive microcline augen; monzonite to granodiorite composition

Lithology: augen gneiss

Ashe Metamorphic Suite and Tallulah Falls Formation; Muscovite-biotite gneiss (Late Proterozoic) at surface, covers 16 % 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 < 0.1 % 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

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

Caesars Head Granite: well foliated, banded to non-banded biotite granitoid gneiss or gneissic granitoid; cuts Seneca thrust fault

Lithology: granitic gneiss

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

Garnetiferous mica schist: aluminous muscovite-biotite schist, locally having subordinate amphibolite layers

Lithology: mica schist; amphibolite

Ashe Metamorphic Suite and Tallulah Falls Formation; Biotite gneiss (Late Proterozoic) at surface, covers 21 % of this area

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

Lithology: biotite gneiss; mica schist; amphibolite

Rocks of Brevard Fault Zone (Uncertain, possibly Permian or Devonian) at surface, covers 5 % of this area

Rocks of Brevard Fault Zone - "fish scale" schist and phyllonite, graphitic; interlayered with feldspathic metasandstone, marble lenses.

Lithology: schist; phyllonite; metasedimentary rock; marble

Quartz Diorite to Granodiorite (Devonian) at surface, covers 9 % 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

Garnet-Mica Schist (Cambrian/Late Proterozoic) at surface, covers 3 % of this area

Garnet-Mica Schist - interlayered with amphibolite.

Lithology: mica schist; amphibolite

Caesars Head Granite Gneiss (Devonian/Silurian) at surface, covers 2 % of this area

Caesars Head Granite Gneiss (409 my) - equigranular to porphyritic, massive to well foliated; contains biotite and muscovite.

Lithology: granitic gneiss

Granite Gneiss (Silurian/Ordovician) at surface, covers 4 % of this area

Granite Gneiss (438 my) - poorly foliated; interlayered with biotite augen gneiss.

Lithology: granitic gneiss; augen gneiss