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

Geologic units in Harnett county, North Carolina

Castle Hayne Formation; Comfort Member and New Hanover Member, undivided (Tertiary) at surface, covers 0.3 % of this area

Comfort Member and New Hanover Member, undivided - Comfort Member: bryozoan-echinoid skeletal limestone, locally dolomitized, solution cavities common. New Hanover Member: phosphate-pebble conglomerate, micritic, thin; restricted to basal part of Castle Hayne Formation in southeastern counties.

Lithology: limestone; dolostone (dolomite); conglomerate

Phyllite and Schist (Cambrian/Late Proterozoic) at surface, covers 5 % 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

Terrace Deposits and Upland Sediment (Tertiary) at surface, covers 5 % of this area

Terrace Deposits and Upland Sediment - gravel, clayey sand, and sand, minor iron-oxide cemented sandstone.

Lithology: terrace; gravel; sand; clay or mud; sandstone

Granitic Rock (Permian/Pennsylvanian) at surface, covers 0.2 % of this area

Granitic Rock (265-325 my) - megacrystic to equigranular. Castalia, Lillington, Medoc Mountain, Sims, Contentnea Creek (?), and Elm City (?) intrusives.

Lithology: granite

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

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

Lithology: metamorphic rock

Black Creek Formation (Cretaceous) at surface, covers < 0.1 % of this area

Black Creek Formation - clay, gray to black, lignitic; contains thin beds and laminae of fine-grained micaceous sand and thick lenses of cross-bedded sand. Glauconitic, fossiliferous clayey sand lenses in upper part.

Lithology: clay or mud; sand

Cape Fear Formation (Cretaceous) at surface, covers 12 % of this area

Cape Fear Formation - sandstone and sandy mudstone, yellowish gray to bluish gray, mottled red to yellowish orange, indurated, graded and laterally continuos bedding, blocky clay, faint cross-bedding, feldspar and mica common.

Lithology: sandstone; mudstone; sand; clay or mud

Middendorf Formation (Cretaceous) at surface, covers 67 % of this area

Middendorf Formation - sand, sandstone, and mudstone, gray to pale gray with an orange cast, mottled; clay balls and iron-cemented concretions common, beds laterally discontinuous, cross-bedding common.

Lithology: sand; sandstone; mudstone; clay or mud

Biotite Gneiss and Schist (Cambrian/Late Proterozoic) at surface, covers 5 % of this area

Biotite Gneiss and Schist - inequigranular, locally 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.

Lithology: biotite gneiss; mica schist; amphibolite; calc-silicate rock; granite

Felsic Mica Gneiss (Cambrian/Late Proterozoic) at surface, covers 6 % of this area

Felsic Mica Gneiss - interlayered with biotite and hornblende gneiss and schist.

Lithology: felsic gneiss; mafic gneiss; biotite gneiss; mica schist

Metavolcanic-Epiclastic Rock (Cambrian/Late Proterozoic) at surface, covers 0.4 % of this area

Metavolcanic-Epiclastic Rock - metamorphosed argillite, mudstone, volcanic sandstone, and conglomerate, and volcanic rock.

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