Geologic units in Chatham county, North Carolina

Felsic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 37 % 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.

Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 20 % of this area

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

Newark Supergroup, Chatham Group; Chatham Group, Undivided (Triassic) at surface, covers 14 % of this area

Conglomerate, fanglomerate, sandstone, and mudstone. Conglomerate and fanglomerate shown by pattern.

Metamorphosed Granitic Rock (Cambrian/Late Proterozoic) at surface, covers 7 % 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.

Mafic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 6 % of this area

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

Newark Supergroup, Chatham Group; Pekin Formation (Triassic) at surface, covers 6 % of this area

Conglomerate, sandstone, and mudstone.

Metavolcanic-Epiclastic Rock (Cambrian/Late Proterozoic) at surface, covers 3 % of this area

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

Intermediate Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 2 % of this area

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

Newark Supergroup, Chatham Group; Sanford Formation (Triassic) at surface, covers 2 % of this area

Conglomerate, fanglomerate, sandstone, and mudstone.

Newark Supergroup, Chatham Group; Cumnock Formation (Triassic) at surface, covers 0.8 % of this area

Sandstone and mudstone, gray to black; coal beds and carbonaceous shale. Grades into Pekin and Sanford formations.

Metamorphosed Granitic Rock (Cambrian/Late Proterozoic) at surface, covers 0.7 % of this area

Megacrystic, well foliated, locally contains hornblende; Vance County suite and Buckhorn granite.

Biotite Gneiss and Schist (Cambrian/Late Proterozoic) at surface, covers 0.6 % of this area

Inequigranular and megacrystic; in places contains garnet; interlayered and gradational with mica schist and amphibolite; includes small masses of granitic rock.

Volcanic Metaconglomerate (Cambrian/Late Proterozoic) at surface, covers 0.5 % of this area

Includes metagraywacke and metamudstone.

Phyllite and Schist (Cambrian/Late Proterozoic) at surface, covers 0.1 % of this area

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

Metamorphosed Gabbro and Diorite (Paleozoic/Late Proterozoic) at surface, covers 0.1 % of this area

Foliated to massive.

Newark Supergroup, Chatham Group; Diabase (Jurassic) at surface, covers < 0.1 % of this area

Diabase - dikes and sills, gray to black.