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Mineral Resources > Online Spatial Data > Geology > by state > Georgia Geology

Geologic units in Richmond county, Georgia

Meta-argillite/ Phyllite (Precambrian-Paleozoic) at surface, covers 4 % of this area

Meta-argillite/ Phyllite

Lithology: metasedimentary rock; phyllite

Lower Tertiary-Cretaceous undifferentiated (Lower Tertiary-Cretaceous) at surface, covers 30 % of this area

Lower Tertiary-Cretaceous undifferentiated, as mapped includes Middendorf Formation (Sloan, 1904); "Channel Sands" (LaMoreaux, 1946); Tuscaloosa Formation (Cooke, 1939); and "Huber beds" (Buie, informal terminology)

Lithology: sand; clay or mud

Stream alluvium (Quaternary) at surface, covers 15 % of this area

Stream alluvium and undifferentiated terrace deposits

Lithology: alluvium; alluvial terrace

McBean Formation (Eocene) at surface, covers 0.6 % of this area

McBean Formation

Lithology: clay or mud

Alluvial Valley Swamp (Quaternary) at surface, covers 0.3 % of this area

Alluvial Valley Swamp: Unconformable on all underlying units, fluvial sand and gravel at base, grading upwards into fine sands and silts, local peat. May be overrun with recent sediments from forest cutting and agriculture.

Lithology: sand; gravel; silt; peat

Socastee Formation (Pleistocene) at surface, covers < 0.1 % of this area

Socastee Formation: Low coastal formation in Carolinas like Penholoway but younger and lower in altitude.

Lithology: sand; clay or mud

Twiggs Clay (Eocene) at surface, covers 15 % of this area

Twiggs Clay

Lithology: clay or mud

Metavolcanic and metasedimentary rocks of Bel Air Belt (Ordovician to Neoproterozoic) at surface, covers < 0.1 % of this area

Metavolcanic and metasedimentary rocks of Bel Air Belt

Lithology: metavolcanic rock; metasedimentary rock

Black Creek/Cusseta/Blufftown Formations (Cretaceous) at surface, covers < 0.1 % of this area

Black Creek/Cusseta/Blufftown Formations: Moderately to poorly sorted sand and clay deposited in delta-dominated shallow marine environments. Unit is characterized by sands containing locally abundant (F-VC grained) tourmaline and (F-VC grained) muscovite with some monazite and garnet. Clay layers are also common and some lower delta plain deposits form commercial kaolin bodies. Generally very restricted marine in eastern Georgia becoming more open marine to the east and west.

Lithology: sand; clay or mud

Felsic Metavolcanics (Precambrian-Paleozoic) at surface, covers 0.2 % of this area

Felsic Metavolcanics

Lithology: felsic metavolcanic rock

Irwinton Sand (Eocene) at surface, covers 33 % of this area

Irwinton Sand (Ei), up-dip equivalent of Twiggs Clay, Sandersville Limestone, and Cooper Marl. As mapped, also includes younger clastics of indefinite Late Tertiary age.

Lithology: sand

Chenier plain and deltas of Suwannee & Chattahoochie Rivers (Holocene) at surface, covers < 0.1 % of this area

Chenier plain and deltas of Suwannee & Chattahoochie Rivers

Lithology: unconsolidated deposit