Geologic units in Craig county, Oklahoma

Additional scientific data in this geographic area

Senora Formation (Middle Pennsylvanian) at surface, covers 22 % of this area

TULSA- Shale with thin and lenticular sandstone, minor limestone, and coal. OKLAHOMA CITY- Mainly fine-grained micaceous sandstone and shale locally containing coal beds. Thickness ranges from about 500 to 950 feet. FORT SMITH- Shale, sandstone, and thin coal seams. ARDMORE-SHERMAN- Shale, gray, and light-brown medium-grained sandstone; thickness, 150 to 500 feet, decreasing southwestward. Subdivided into lower sandstone, 350 feet thick, and upper shale, 150 feet thick.

Savanna Formation (Middle Pennsylvanian) at surface, covers 19 % of this area

TULSA- "Savanna Formation," shale and thin sandstone, limestone, and coal. FORT SMITH- IPsa "Savanna Formation," shale, sandstone, and coal ARDMORE-SHERMAN- Sandstone and shale, gray to brown, fine- to coarse-grained, cherty, with several thin coal seams near middle; thickness, 1,120 to 1,600 feet (Lower Franks Conglomerate) McALESTER TEXARKANA- Shale, tan to brown, illitic, chloritic, and sandstone, fine-to coarse-grained, micaceous, quartzose, with several thin coal seams in middle, one of which is "Cavanal coal;" thickness, 1,470 to 2,000 feet, increasing eastward.

Fort Scott Limestone (Middle Pennsylvanian) at surface, covers 14 % of this area

TULSA- Limestone and shale. (Mapped with the Labette Formation south of Bird Creek inTulsa County).

Boggy Formation (Middle Pennsylvanian) at surface, covers 9 % of this area

TULSA- Shale, sandstone, and coal. FORT SMITH- Shale, sandstone, and coal; includes Bluejacket Sandstone Member at base. ARDMORE-SHERMAN- Shale and sandstone, blue-gray to brown, fine- to coarse- grained, with some thin limestone lenses and a coal bed 2.5 feet thick about 400 feet above base. Thickness, 1,250 to 2,800 feet. "Bluejacket Sandstone," IPbj, at base, 8 to 12 feet thick, with 2-foot "Secor coal" 50 feet above top of Bluejacket. (Lower Franks Conglomerate) McALESTER TEXARKANA- Shale, brown, to blue-gray, illitic, chloritic, with many sandstones, fine- to coarse-grained, micaceous, quartzose, moderately to well-indurated, with "Secor coal" about 50 feet above base; thickness, 2,140 to 4,000 feet, increasing eastward.

McAlester and Hartshorne Formations (Middle Pennsylvanian) at surface, covers 9 % of this area

TULSA- "McAlester and Hartshorne Formations", shale and some sandstone and coal. FORT SMITH- IPmh "McAlester" and "Hartshorne Formations" (undifferentiated), shale, sandstone, and coal.

Pitkin + Fayetteville + Batesville + Hindsville + Moorefield Formations (Late Mississippian) at surface, covers 7 % of this area

TULSA- "Pitkin Formation," limestone. "Fayetteville Formation," shale and thin limestone. "Batesville Formation," fine-grained sandstone. "Hindsville Formation," limestone and shale. "Moorefield Formation," limestone, shale, and siltstone.

Keokuk and Reeds Spring Formations and St. Joe Group (Early Mississippian) at surface, covers 6 % 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.

Labette Formation (Middle Pennsylvanian) at surface, covers 5 % of this area

TULSA- Shale and thin sandstone and limestone.

Alluvium (Holocene) at surface, covers 5 % 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.

Oolagah Formation (Middle Pennsylvanian) at surface, covers 4 % of this area

TULSA- Thin-bedded limestone and some shale in the southern part of the area. North of Oolagah, in western Rogers County, the map unit, IPol, includes the following formations: "Altamont Formation," limestone and minor shale; "Bandera Formation," shale and thin sandstone; "Pawnee Formation," limestone and minor shale.

Atoka Formation (Middle Pennsylvanian) at surface, covers 0.2 % 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.

Marmaton Group (Early Pennsylvanian- Desmoinesian) at surface, covers < 0.1 % of this area

Includes: Lost Branch FM, Memorial Shale, Lenapah Limestone (base LE), Nowata Shale, Altamont Limestone (base PA), Bandera Shale, Pawnee Limestone (base PA), Labette Shale and Fort Scott Limestone.

Savanna + McAlester + Hartshorne + Atoka Formations (Middle Pennsylvanian) at surface, covers < 0.1 % of this area

TULSA- "Savanna, McAlester, Hartshorne, and Atoka Formations," shale, sandstone, siltstone, limestone, and coal.