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

Geologic units in Washington county, Arkansas

[Additional scientific data in this geographic area]

Bloyd and Hale Formations (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Early) at surface, covers < 0.1 % of this area

TULSA- "Bloyd Formation," limestone and shale. "Hale Formation," limestone and sandstone. FORT SMITH- IPbh "Bloyd Formation," shale and limestone; and "Hale Formation," limestone and sandstone.

Lithology: limestone; shale; sandstone

Atoka Formation, undivided (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle [Atokan] ) at surface, covers 24 % of this area

Atoka Formation, undivided

Lithology: sandstone; shale; coal

Pitkin Limestone, Fayetteville Shale (including the Wedington Sandstone member), and Batesville Sandstone (including the Hindsville Limestone Member) (Phanerozoic | Paleozoic | Carboniferous Mississippian-Late [Chesterian]) at surface, covers 25 % of this area

Pitkin Limestone, Fayetteville Shale (including the Wedington Sandstone member), and Batesville Sandstone (including the Hindsville Limestone Member)

Lithology: sandstone; shale; limestone

Pitkin + Fayetteville + Hindsville + Moorefield Formations (Phanerozoic | Paleozoic | Carboniferous Mississippian-Late) at surface, covers < 0.1 % of this area

FORT SMITH- Mp "Pitkin Formation," limestone; "Fayetteville Formation," shale and limestone; "Hindsville Formation," limestone and shale; and "Moorefield Formation," limestone.

Lithology: limestone; shale

Bloyd Shale, and Prairie Grove Member of the Hale Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle [Morrowan]) at surface, covers 14 % of this area

Bloyd Shale, and Prairie Grove Member of the Hale Formation

Lithology: sandstone; shale; limestone; conglomerate

Cane Hill Member of Hale Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Early [Morrowan]) at surface, covers 5 % of this area

Cane Hill Member of Hale Formation

Lithology: sandstone; siltstone; conglomerate

Atoka Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle) at surface, covers < 0.1 % of this area

TULSA- IPat "Atoka Formation," shale, siltstone, sandstone, and thin limestone. FORT SMITH- IPat "Atoka Formation," shale and sandstone. ARDMORE-SHERMAN- Shale, dark-gray, and sandstone, buff to white, fine- to coarse-grained, with some chert conglomerates; thickness, 800 to 3,000 feet. McALESTER TEXARKANA- Shale, gray to tan, illitic, chloritic, with many sandstones, fine- to coarse-grained, quartzose, micaceous, well- to poorly sorted; "Fanshawe" and "Red Oak Sandstones" in middle and "Spiro Sandstone" at base; thickness, 3,000 to 10,000 feet, increasing southeastward in subsurface, south of growth faults.

Lithology: shale; sandstone; siltstone; limestone; conglomerate

Chattanooga Shale (Lower Mississippian and Upper Devonian), Clifty Limestone (Middle Devonian), and Penters Chert (Lower Devonian) (Phanerozoic | Paleozoic | Devonian-Early Devonian-Middle(?) Devonian-Late(?) Carboniferous Mississippian-Early) at surface, covers 0.6 % of this area

Chattanooga Shale (Lower Mississippian and Upper Devonian), Clifty Limestone (Middle Devonian), and Penters Chert (Lower Devonian)

Lithology: shale; limestone; dolostone (dolomite); sandstone; siltstone; chert

Alluvium (Phanerozoic | Cenozoic | Quaternary | Holocene) at surface, covers < 0.1 % of this area

WOODWARD- Lenticular and interfingering deposits of gravel, sand, silt, and clay. Generally light-tan to gray. Thickness along major streams ranges up to 100 feet and probably averages 40 feet; along minor streams the thickness ranges up to 45 feet and probably averages 20 feet. ENID- Sand, silt, clay, and locally gravel. Maximum thickness ranges from 30 to 80 feet (9 to 24 m) along major streams and from 0 to 60 feet (0 to 18 m) along minor streams. TULSA- Gravel, sand, silt, and clay. TULSA- Gravel, sand, silt, and clay. OKLAHOMA CITY- Sand, silt, clay, and lenticular beds of gravel. Thickness ranges from about 30 to 100 feet and probably averages about 50 feet along major streams. Along minor streams, thickness ranges from a few feet to about 50 feet and probably averages about 25 feet. LAWTON- Sand, clay, and gravel as much as 50 feet (15 m) thick; Shown only along major streams and tributaries . ARDMORE-SHERMAN- Gravel, sand, silt, and clay, including low terraces; thickness, about 25 to 100 feet. McALESTER TEXARKANA- Gravel, sand, silt, and clay, including low terraces about 30 feet above channels; thickness, about 50 feet along Little River and 110 feet along Red River

Lithology: alluvium

Keokuk and Reeds Spring Formations and St. Joe Group (Phanerozoic | Paleozoic | Carboniferous Mississippian-Early) at surface, covers < 0.1 % of this area

TULSA- "Keokuk Formation," chert and limestone. "Reeds Spring Formation," chert and limestone. "St. Joe Group," limestone and shale. FORT SMITH- Mkr "Keokuk Formation," chert; "Reeds Spring Formation," chert and limestone; and "St. Joe 'Group,'" limestone and marlstone.

Lithology: chert; limestone; shale; carbonate

Boone Formation (Phanerozoic | Paleozoic | Carboniferous Mississippian-Early [Meramecian Osagean]) at surface, covers 31 % of this area

Boone Formation

Lithology: limestone; chert; shale