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

Geologic units in Johnston county, North Carolina

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 16 % 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

Felsic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 7 % 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

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

Amphibolite - equigranular, massive to well foliated, dioritic to basaltic dikes and sills; variably metamorphosed.

Lithology: amphibolite; basalt; diorite

Black Creek Formation (Cretaceous) at surface, covers 13 % 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

Phyllite and Schist (Cambrian/Late Proterozoic) at surface, covers 4 % 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 17 % 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

Castle Hayne Formation; Comfort Member and New Hanover Member, undivided (Tertiary) at surface, covers 0.2 % 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

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

Injected Gneiss - biotite gneiss and schist intruded by numerous sills and dikes of granite, pegmatite, and aplite; minor hornblende gneiss.

Lithology: biotite gneiss; schist; granite; pegmatite; aplite; mafic gneiss

Biotite Gneiss and Schist (Cambrian/Late Proterozoic) at surface, covers 10 % 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

Foliated to Massive Granitic Rock (Permian/Pennsylvanian) at surface, covers 6 % of this area

Foliated to Massive Granitic Rock (270-320my) - megacrystic to equigranular. Butterwood Creek intrusive and Rocky Mount intrusive suite.

Lithology: granite

Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 0.9 % 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

Yorktown Formation and Duplin Formation, Undivided (Tertiary) at surface, covers 13 % of this area

Yorktown Formation and Duplin Formation, Undivided - Yorktown Formation: fossiliferous clay with varying amounts of fine-grained sand, bluish gray, shell material commonly concentrated in lenses; mainly in area north of Neuse River. Duplin Formation: shelly, medium- to coarse-grained sand, sandy marl, and limestone, bluish gray; mainly in area south of Neuse River.

Lithology: clay or mud; sand; limestone