Geologic units in Guilford county, North Carolina

Metamorphosed Granitic Rock (Cambrian/Late Proterozoic) at surface, covers 52 % 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.

Granitic Rock (Permian/Pennsylvanian) at surface, covers 22 % of this area

Megacrystic to equigranular. Churchland Plutonic Suite (Western group) - Churchland, Landis, and Mooresville intrusives.

Metamorphosed Gabbro and Diorite (Paleozoic/Late Proterozoic) at surface, covers 13 % of this area

Foliated to massive.

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

Inequigranular and megacrystic; 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.

Mafic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 4 % of this area

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

Felsic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 2 % 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.

Intermediate Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 1.0 % of this area

Metamorphosed andesitic tuffs and flows, medium to dark grayish green; minor felsic and mafic metavolcanic rock.

Uwharrie Formation; Felsic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 0.8 % 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.

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

Interbedded felsic to mafic tuffs and flowrock.

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

Metamorphosed dunite and peridotite; serpentine, soapstone, and other altered ultramafic rock. Only larger bodies shown.