USGS Home
Contact USGS
Search USGS

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

Geologic units in Union county, North Carolina

Metamorphosed granite and granodiorite (Cambrian or Neoproterozoic) at surface, covers < 0.1 % of this area

Metamorphosed granite and granodiorite

Lithology: granite; granodiorite

Felsic metavolcanic rocks and felsic gneiss interpreted to the metavolcanics (Ordovician to Neoproterozoic) at surface, covers < 0.1 % of this area

Felsic metavolcanic rocks and felsic gneiss interpreted to the metavolcanics

Lithology: felsic metavolcanic rock; gneiss

Gabbro of Concord Plutonic Suite (Devonian/Ordovician) at surface, covers 2 % of this area

Gabbro of Concord Plutonic Suite (399-479 my) - Barber, Concord, Farmington, Mecklenburg, and Weddington intrusives.

Lithology: gabbro

Floyd Church Formation; Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 10 % of this area

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

Lithology: meta-argillite; meta-conglomerate; metasedimentary rock; metavolcanic rock

Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 0.2 % of this area

Metamudstone and Meta-Argillite - bedding plane and axial-planar cleavage common; interbedded with metasandstone, meta-conglomerate, and metavolcanic rock.

Lithology: metasedimentary rock; meta-argillite; meta-conglomerate; metavolcanic rock

Granite of Salisbury Plutonic Suite (Devonian/Silurian) at surface, covers 0.9 % of this area

Granite of Salisbury Plutonic Suite (385-415 my) - pink, massive to weakly foliated. Gold Hill, Kannapolis, Salisbury, Southmont, and Yadkin intrusives.

Lithology: granite

Tuffaceous metasiltstone (Early Paleozoic-Neoproterozoic) at surface, covers < 0.1 % of this area

Tuffaceous metasiltstone

Lithology: metasedimentary rock

Metamorphosed Quartz Diorite (Paleozoic/Late Proterozoic) at surface, covers 0.2 % of this area

Metamorphosed Quartz Diorite - foliated to massive.

Lithology: metamorphic rock

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

(southwest of Asheboro); Felsic Metavolcanic Rock - metamorphosed dacitic to rhyolitic flows and tuffs, light gray to greenish gray; interbedded with mafic and intermediate metavolcanic rock, meta-argillite, and metamudstone.

Lithology: felsic metavolcanic rock; mafic metavolcanic rock; intermediate metavolcanic rock; meta-argillite; metasedimentary rock

Cid Formation; Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 57 % of this area

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

Lithology: meta-argillite; meta-conglomerate; metasedimentary rock; metavolcanic rock

Metamorphosed Mafic Rock (Paleozoic/Late Proterozoic) at surface, covers 1 % of this area

Metamorphosed Mafic Rock - metagabbro, metadiorite, and mafic plutonic-volcanic complexes.

Lithology: metamorphic rock

Waxhaw metagranite (Ordovician to Cambrian) at surface, covers < 0.1 % of this area

Waxhaw metagranite: metamorphosed fine- to medium-grained biotite granite and hypabyssal quartz porphyry, non-foliated except adjacent to Gold Hill and Waxhaw shear zones where it is gneissic to phyllonitic

Lithology: granite

Chatham Group, undivided (Triassic) at surface, covers < 0.1 % of this area

Chatham Group, undivided: conglomerate, sandstone and mudstone

Lithology: conglomerate; sandstone; mudstone

Newark Supergroup, Chatham Group; Chatham Group, Undivided (Triassic) at surface, covers 1 % of this area

Chatham Group, Undivided - conglomerate, fanglomerate, sandstone, and mudstone. Conglomerate and fanglomerate shown by pattern.

Lithology: conglomerate; sandstone; mudstone

Granitic Rock (Devonian/Ordovician) at surface, covers 0.2 % of this area

Granitic Rock - locally pinkish gray, massive to weakly foliated; contains hornblende.

Lithology: granite

Phyllite and Schist (Cambrian/Late Proterozoic) at surface, covers 11 % of this area

Phyllite and Schist - minor biotite and pyrite; includes phyllonite, sheared fine-grained metasediment and metavolcanic rock.

Lithology: phyllite; schist; phyllonite; metasedimentary rock; metavolcanic rock

Phyllonite and phyllonitic schist (Late Paleozoic) at surface, covers < 0.1 % of this area

Phyllonite and phyllonitic schist

Lithology: phyllonite; schist

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

Metamorphosed Granitic Rock (520-650 my) - megacrystic, well foliated, locally contains hornblende; Fountain intrusive.

Lithology: metamorphic rock

Persimmon Fork Formation (Cambrian to Neoproterozoic) at surface, covers 0.2 % of this area

Persimmon Fork Formation: predominately metatuff

Lithology: metavolcanic rock

Felsic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 10 % of this area

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

Lithology: felsic metavolcanic rock; mafic metavolcanic rock; intermediate metavolcanic rock; meta-argillite; metasedimentary rock

Cid Formation, Mudstone Member (Ordovician to Late Cambrian) at surface, covers 0.2 % of this area

Cid Formation, Mudstone Member: thin bedded tuffaceous metasiltstone

Lithology: metasedimentary rock

Metadiorite (Cambrian or Neoproterozoic) at surface, covers < 0.1 % of this area

Metadiorite

Lithology: diorite

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

Metavolcanic Rock - interbedded felsic to mafic tuffs and flowrock.

Lithology: felsic metavolcanic rock; mafic metavolcanic rock