USGS Home
Contact USGS
Search USGS

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

Geologic units in Clark county, Arkansas

Brownstown Marl (Phanerozoic | Mesozoic | Cretaceous-Late) at surface, covers 5 % of this area

Brownstown Marl

Lithology: mixed clastic/carbonate; sand; limestone

Nacatoch Sand (Phanerozoic | Mesozoic | Cretaceous-Late) at surface, covers 6 % of this area

Nacatoch Sand

Lithology: sand; limestone; clay or mud; mixed clastic/carbonate

Ozan Formation (Phanerozoic | Mesozoic | Cretaceous-Late) at surface, covers 3 % of this area

Ozan Formation

Lithology: mixed clastic/carbonate

Marlbrook Marl (Phanerozoic | Mesozoic | Cretaceous-Late) at surface, covers 2 % of this area

Marlbrook Marl

Lithology: mixed clastic/carbonate

Wilcox Group (Phanerozoic | Cenozoic | Tertiary | Eocene-Early) at surface, covers 8 % of this area

Wilcox Group

Lithology: sand; silt; clay or mud; gravel; coal

Jackfork Sandstone (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Early [Morrowan]) at surface, covers 8 % of this area

Jackfork Sandstone

Lithology: sandstone; shale

Tokio Formation (Phanerozoic | Mesozoic | Cretaceous-Late) at surface, covers 2 % of this area

Tokio Formation

Lithology: clay or mud; sand; coal; novaculite

Arkadelphia Marl (Phanerozoic | Mesozoic | Cretaceous-Late) at surface, covers 4 % of this area

Arkadelphia Marl

Lithology: mixed clastic/carbonate; clay or mud; sandstone; limestone

Stanley Shale (Phanerozoic | Paleozoic | Carboniferous Mississippian-Early) at surface, covers 11 % of this area

Stanley Shale - Includes Chickasaw Creek Chert equivalent of Harlton (1938) near top and Hatton Tuff Lentil and Hot Springs Sandstone Member near base

Lithology: shale; sandstone; siltstone; chert; tuff

Terrace deposits (Phanerozoic | Cenozoic | Quaternary | Pleistocene-Late) at surface, covers 6 % of this area

Terrace deposits - Alluvial deposits on one or more terrace levels

Lithology: alluvial terrace

Sartoga Chalk (Phanerozoic | Mesozoic | Cretaceous-Late) at surface, covers 2 % of this area

Sartoga Chalk

Lithology: limestone; sand

Arkansas Novaculite (Phanerozoic | Paleozoic | Devonian-Late Carboniferous Mississippian-Early) at surface, covers < 0.1 % of this area

Arkansas Novaculite - Includes upper division (Mississippian), middle division (Mississippian and Devonian), and lower division (Devonian)

Lithology: novaculite; shale

Johns Valley Shale (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Early [Morrowan]) at surface, covers 3 % of this area

Johns Valley Shale

Lithology: shale; sandstone; limestone

Alluvium (Phanerozoic | Cenozoic | Quaternary | Holocene) at surface, covers 29 % of this area

Alluvium - Alluvial deposits of present streams

Lithology: alluvium

Atoka Formation - Lower part (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle [Atokan]) at surface, covers 4 % of this area

Atoka Formation - Lower part

Lithology: sandstone; shale

Midway Group (Phanerozoic | Cenozoic | Tertiary | Paleocene) at surface, covers 5 % of this area

Midway Group

Lithology: clay or mud; mixed clastic/carbonate; sandstone; limestone