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Geologic units in Randolph county, North Carolina

Uwharrie Formation; Felsic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 31 % of this area

(At Asheboro and to south) Metamorphosed dacitic to rhyolitic flows and tuffs, light gray to greenish gray; interbedded with mafic and intermediate metavolcanic rock, meta-argillite, and metamudstone.

Metamorphosed Granitic Rock (Cambrian/Late Proterozoic) at surface, covers 16 % of this area

Megacrystic, well foliated; locally contains hornblende. Chapel Hill, Chatham, Farrington, Meadow Flats, Mt. Moriah, Parks Crossroads plutons, and Roxboro and Vance County suites.

Tillery Formation; Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 15 % of this area

(Southwest of Asheboro) Thin to thick bedded; bedding plane and axial-planar cleavage common; interbedded with metasandstone, metaconglomerate, and metavolcanic rock.

Metavolcanic-Epiclastic Rock (Cambrian/Late Proterozoic) at surface, covers 11 % of this area

Metamorphosed argillite, mudstone, volcanic sandstone, conglomerate, and volcanic rock.

Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 9 % of this area

Thin to thick bedded; bedding plane and axial-planar cleavage common; interbedded with metasandstone, metaconglomerate, and metavolcanic rock.

Felsic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 5 % of this area

Metamorphosed dacitic to rhyolitic flows and tuffs, light gray to greenish gray; interbedded with mafic and intermediate metavolcanic rock, meta-argillite, and metamudstone.

Mafic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 5 % of this area

Metamorphosed basaltic flows and tuffs, dark green to black; interbedded with felsic and intermediate metavolcanic rock and metamudstone.

Cid Formation; Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 3 % of this area

(Southwest of Asheboro) Thin to thick bedded; bedding plane and axial-planar cleavage common; interbedded with metasandstone, metaconglomerate, and metavolcanic rock.

Cid Formation; Mafic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 2 % of this area

(Southwest of Asheboro) Metamorphosed basaltic flows and tuffs, dark green to black; interbedded with felsic and intermediate metavolcanic rock and metamudstone.

Metamorphosed Gabbro and Diorite (Paleozoic/Late Proterozoic) at surface, covers 2 % of this area

Foliated to massive.

Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 0.6 % of this area

Interbedded felsic to mafic tuffs and flowrock.

Phyllite and Schist (Cambrian/Late Proterozoic) at surface, covers 0.2 % of this area

Locally laminated and pyritic; includes phyllonite, sheared fine-grained metasediment, and metavolcanic rock. In Lilesville granite aureole, includes hornfels.

Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers < 0.1 % of this area

Interbedded felsic to mafic tuffs and flowrock.