Geologic units containing bentonite

Mineral Resources On-Line Spatial Data

Bentonite

A soft, plastic, porous, light-colored rock composed essentially of clay minerals of the montmorillonite (smectite) group plus colloidal silica, and produced by devitrification and accompanying chemical alteration of a glassy igneous material, usually a tuff or volcanic ash.

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Alabama

Colvin Mountain Sandstone (Ordovician): Colvin Mountain Sandstone - light-gray quartzose sandstone, pebbly in part. Locally contains thin beds of bentonite in the upper part.
Little Oak and Newala Limestones undifferentiated (Ordovician): Little Oak and Newala Limestones undifferentiated - Little Oak Limestone -- dark-gray medium to thick-bedded fossiliferous, argillaceous to silty limestone containing chert nodules. Locally includes thin beds of bentonite in the upper part. Newala Limestone -- light to dark-gray thick-bedded micritic and peloidal limestone and minor dolomite.
Little Oak Limestone (Ordovician): Little Oak Limestone - dark-gray medium to thick-bedded fossiliferous, argillaceous to silty limestone containing chert nodules. Locally includes thin beds of bentonite in the upper part.
Nashville and Stones River Groups undifferentiated (Ordovician): Nashville and Stones River Groups undifferentiated - medium to dark-gray fossiliferous limestone, argillaceous in part; yellowish-gray laminated silty limestone in upper part. Contains one or more thin beds of bentonite and bentonitic shale.
Oligocene Series undifferentiated (Oligocene): Oligocene Series undifferentiated - Descriptions of the units of the Oligocene Series follow in descending order. Paynes Hammock Sand - locally fossiliferous, calcareous, argillaceous medium to coarse sand; pale-blue-green clay; and thin-bedded sandy limestone; exposed at Paynes Hammock and at St. Stephens. Chickasawhay Limestone - white to yellowish-gray fossiliferous, glauconitic limestone and soft marl. Byram Formation includes three members in descending order: Bucatunna Clay Member - dark, bentonitic, carbonaceous, sparsely fossiliferous clay and greyish-yellow sand; unnamed marl member - light-grey to yellowish-grey sandy, glauconitic , fossiliferous marl; Glendon Limestone Member - irregularly indurated coquinoid and crystalline limestone, weathering to indurated rock containing large tubular cavities, locally known as 'horsebone'. Marianna Limestone - white to yellowish-grey soft, porous, very fossiliferous limestone. Forest Hill sand - dark-greenish-grey carbonaceous clay with lenses of glauconitic fossiliferous sand; extends eastward from MS into Choctaw, Clarke and Washington Counties. Red Bluff Clay - greenish-gray calcareous clay locally containing selenite crystals, yellowish-grey glauconitic, fossiliferous limestone; and light-gray silty clay with interbeds of sand (Forest Hill equivalent); from Tombigbee River eastward grades into glauconitic fossiliferous limestone equivalent to the Bumpnose Limestone. Bumpnose Limestone - very light-gray to yellowish-gray chalky, subcoquinoid, glauconitic, argillaceous, fossiliferous limestone; intertongues with Red Bluff Clay in vicinity of the Alabama River and is readily differentiated eastward from the Sepulga River.
Sequatchie Formation, Colvin Mountain Sandstone, Greensport Formation undifferentiated (Ordovician): Sequatchie Formation, Colvin Mountain Sandstone, Greensport Formation undifferentiated - variegated dusky-red and pale-yellowish-orange shale, calcareous mudstone, dolomite, siltstone, and minor sandstone. Mapped in areas of facies transition with the Chickamauga Limestone (Scraper Mountain) and in the structurally complex area at the east end of Dry Creek Mountain.
Stones River Groups undifferentiated in part (Ordovician): Stones River Groups undifferentiated in part - medium to dark-gray thick to thin-bedded limestone, argillaceous in part, locally very fossiliferous. Contains a zone of bentonite and bentonitic shale near the top. Mapped seperately from the Nashville Group only in Jackson County.

Arizona

Cretaceous sedimentary rocks (Cretaceous): Tan sandstone (Dakota Sandstone) overlain by gray shale (Mancos Shale); deposited in beach, river delta, and shallow sea settings. The Mancos Shale is overlain by the Mesaverde Group (map unit Kmv). This unit includes related sandstone and shale exposed near Show Low, Morenci (Pinkard Formation), and around Deer Creek south of Globe. (about 88-97 Ma)
San Rafael Group (Middle to Late Jurassic): Commonly cross-bedded, ledge-forming sandstone and slope-forming siltstone. Rock typically has a striped red and white aspect. The Carmel Formation and Entrada Sandstone are prominent members of this group. (Late to Middle Jurassic, about 160-180 Ma)

Colorado

Pierre Shale--Lower unit (Phanerozoic | Mesozoic | Cretaceous): Sharon Springs Member (organic-rich shale and numerous bentonite beds) in lower part

Idaho

Tuffaceous shale, sandstone, conglomerate, and lignite; Eocene to Pliocene alluvial and lacustrine deposits; central and southern Idaho (Tertiary): Tertiary continental sediments; predominantly Upper Tertiary in age; subdivisions are:(Tpd, Tmd, and Ted).

Mississippi

Vicksburg group and Chickasawhay limestone (Oligocene): Vicksburg group and Chickasawhay limestone - Chickasawhay limestone, sandy limestone, and sand, present only in eastern MS (mapped with it is the overlying Paynes Hammock sand of Miocene age); Vicksburg group, predominantly limestone and marl, but contains some bentonite and near the top, chocolate-colored clay and some sand.

Montana

Bearpaw shale (Phanerozoic | Mesozoic | Cretaceous-Late): Bearpaw shale: Dark-gray and brownish clay shale; thick units of nonfissile bentonitic shale; calcareous and ferruginous concretions throughout; contains some thick bentonite beds.
Belle Fourche shale (Phanerozoic | Mesozoic | Cretaceous-Late): Belle Fourche shale: dark blue-gray siliceous shale with many calcareous and ferruginous concretions and intercalated thin layers of bentonite.
Claggett formation (Phanerozoic | Mesozoic | Cretaceous-Late): Claggett formation: chiefly dark-gray shale with iron-stained concretions; locally sandstone present; numerous bentonite beds near base.
Frontier formation (Phanerozoic | Mesozoic | Cretaceous-Late): Frontier formation: mainly gray sandy shale; locally Torchlight sandstone member constitutes upper third and thinner Peay sandstone member is at base; contains some thick beds of bentonite.
Greenhorn formation (Phanerozoic | Mesozoic | Cretaceous-Late): Greenhorn formation: mainly light-gray marl and calcareous shale.
Mowry shale (Phanerozoic | Mesozoic | Cretaceous-Early): Mowry shale: chiefly light-gray silicified shale and claystone with minor amounts of sandy shale and sandstone; contains some thick beds of bentonite.
Niobrara formation (Phanerozoic | Mesozoic | Cretaceous-Late): Niobrara formation: chiefly calcareous shale with limestone concretions; many thin bentonite beds locally.
Pierre shale (Phanerozoic | Mesozoic | Cretaceous-Late): Pierre shale: dark-gray clay shale with calcareous and ferruginous concretions and sandy members.
Tertiary sedimentary rocks, undifferentiated (Phanerozoic | Cenozoic | Tertiary): Tertiary sedimentary rocks, undifferentiated: clastic deposits in western Montana, mostly in valleys, and in most places not divided into formations; mostly poorly consolidated gravel, sand, silt, and clay; includes some tuffaceous material and locally lenses of lignite and bentonite; a little hot spring tufa; and in areas not yet mapped in detail, lava may be included. These rocks were in part laid down in lakes but a large part was formed in streams and alluvial fans. These rocks are Tertiary in age and as now mapped may even include some beds of Cretaceous age. Some late Tertiary terrace deposits may be included.
Thermopolis shale (Phanerozoic | Mesozoic | Cretaceous-Early): Thermopolis shale: dark-gray shale with some sandstone. The subsurface consists of Muddy sandstone member or Newcastle sandstone member at top, Skull Creek shale member in middle, and Fall River sandstone or First Cat Creek sand of drillers at base.
Two Medicine formation (Phanerozoic | Mesozoic | Cretaceous-Late): Two Medicine formation: greenish-gray clay with local nodular limestone and crossbedded sandstone; locally some coal in lower part. Rocks equivalent to Judith River formation, Claggett formation, and upper part of Eagle sandstone are included in this unit.

New Mexico

Grayburg and Queen Fromations (Phanerozoic | Paleozoic | Permian): Grayburg and Queen Formations; sandstone, gypsum, anhydrite, dolomite, and red mudstone; Guadalupian

Pennsylvania

Hamilton Group (Devonian): Hamilton Group - Includes, in descending order, the Mahantango (Dmh) and Marcellus (Dmr) Formations.
Marcellus Formation (Devonian): Marcellus Formation - Black shale; sparse marine fauna and siderite concretions. Contains local limestone ("Purcell") member. Tioga bentonite included at base in eastern Pennsylvania.
Onondaga and Old Port Formations, undivided (Devonian): Onondaga and Old Port Formations, undivided - Includes, in descending order, the Onondaga Formation (Don), Ridgeley Member of Old Port Formation (Dor), and Shriver, Mandata, Corriganville, and New Creek Members of Old Port Formation, undivided (Dosn).
Onondaga Formation (Devonian): Onondaga Formation - Medium-gray calcareous shale; marine fossils; medium-gray argillaceous limestone of Selinsgrove Member at top; called "Needmore Formation" west of 78° longitude; Tioga bentonite at top.

Tennessee

Bays Formation (Ordovician): Bays Formation - Maroon, well-jointed claystone and siltstone, commonly mottled greenish, evenly bedded; light- gray sandstone beds and metabentonite in upper part. Maximum thickness 1,000 feet.
Bays Formation (Ordovician): Bays Formation - Maroon claystone and siltstone, commonly mottled greenish, evenly bedded; to northeast, light- gray to white, thick-bedded sandstone; metabentonite in upper part. Maximum thickness 1,000 feet.
Carters Limestone (Ordovician): Carters Limestone - Fine-grained, yellowish-brown limestone; thin-bedded in upper part; thicker bedded and very slightly cherty with scattered mottlings of magnesian limestone in lower part. Contains thin bentonite beds. Thickness 60 to 250 feet.
Martinsburg Shale, including Reedsville Shale and Unnamed Limestone Unit (Ordovician): Martinsburg Shale - Bluish-gray, calcareous clay shale, weathers yellowish-brown; with thin beds of nodular gray, fossiliferous limestone; thin layers of metabentonite near base. Thickness about 1,000 feet. Incluldes Reedsville Shale - Greenish-gray calcareous shale. Thickness 200 to 400 feet. and Unnamed Limestone Unit - Medium-grained, fossiliferous, gray limestone, shaly in part. Thickness as much as 600 feet.
Middle and Lower Parts of Chickamauga Group, including Mocassin Formation, Bays Formation, Sevier Shale, Ottosee Shale, Holston Formation, Lenoir Limestone and Athens Shale (Ordovician): Middle and Lower Parts of Chickamauga Group - A sequence of about 1,400 feet of limestone in the northeast, which thickens and becomes more clastic to the southeast and is divided into the formations shown at right. Maximum thickness about 8,000 feet. Includes Mocassin Formation - Maroon calcareous shale, siltstone, and limestone; thin metabentonite layers in upper part; mud cracks, ripple marks common. Thickness 800 to 1,000 feet; (Ob) Bays Formation - Maroon claystone and siltstone, commonly mottled greenish, evenly bedded; to northeast, light- gray to white, thick-bedded sandstone; metabentonite in upper part. Maximum thickness 1,000 feet. (Osv) Sevier Shale - Calcareous, bluish-gray shale, weathers yellowish-brown; with thin gray limestone layers; sandstone, siltstone, and locally conglomerate to the east. Thickness 2,000 to 7,000 feet; (Oo) - Ottosee Shale - Bluish-gray calcareous shale, weathers yellow; with reef lenses of coarsely crystalline reddish fossiliferous limestone ("marble"). Thickness about 1,000 feet; (Oh) - Holston Formation - Pink, gray, and red coarsely crystalline limestone (Holston Marble); in many areas upper part is sandy, crossbedded ferruginous limestone and brown to greenish calcareous shale. Thickness 200 to 600 feet; (Ol) Lenoir Limestone - Nodular, argillaceous, gray limestone; in places basal sedimentary breccia, conglomerate, quartz sand; Mosheim Limestone Member (dense, light- to medium-gray limestone) near base. Thickness 25 to 500 feet; (Oa) Athens Shale - Medium- to dark-gray, calcareous, graptolitic shale; calcareous gray sandstone, siltstone, and locally fine-pebble quartz conglomerate; nodules of shaly limestone near base. Maximum thickness 1,500 feet.
Middle and Lower parts of Chickamauga Group, including Moccassin Formation, Bays Formation, Sevier Shale, Ottosee Shale, Holston Formation, Lenoir Limestone, and Athens Shale (Ordovician): Middle and Lower Parts of Chickamauga Group - A sequence of about 1,400 feet of limestone in the northwest part of Valley and Ridge, which thickens and becomes more clastic to the southeast and is divided into the formations shown at right. Maximum thickness about 7,000 feet. Includes Moccasin Formation - Maroon calcareous shale, siltstone, and limestone; thin metabentonite layers in upper part; mud cracks, ripple marks common. Thickness 800 to 1,000 feet;. (Ob) Bays Formation - Maroon, well-jointed claystone and siltstone, commonly mottled greenish, evenly bedded; light- gray sandstone beds and metabentonite in upper part. Maximum thickness 1,000 feet; (Osv) Sevier Shale - Calcareous, bluish-gray shale, weathers yellowish-brown; with thin, gray limestone layers; sandstone, siltstone, and locally conglomerate to the east. Thickness 2,000 to 7,000 feet; (Oo) Ottosee Shale - Bluish-gray calcareous shale, weathers yellow; with reef lenses of coarsely crystalline reddish fossiliferous limestone ("marble"). Thickness about 1,000 feet; (Oh) Holston Formation - Pink, gray, and red coarsely crystalline limestone (Holston Marble); in many areas upper part is sandy, crossbedded ferruginous limestone and brown to greenish calcareous shale. Thickness 200 to 600 feet; (Ol) Lenoir Limestone - Nodular, argillaceous, gray limestone; in places basal sedimentary breccia, conglomerate, quartz sand; Mosheim Limestone Member (dense, light- to medium-gray limestone) near base. Thickness 25 to 500 feet; (Oa) Athens Shale - Medium- to dark-gray, calcareous, graptolitic shale; calcareous gray sandstone, siltstone, and locally fine-pebble quartz conglomerate; nodules of shaly limestone near base. Maximum thickness 1,500 feet.
Stones River Group; Carters Limestone (Ordovician): Stones River Group; Carters Limestone - Fine-grained, yellowish-brown limestone; thin-bedded in upper part; thicker bedded and very slightly cherty with scattered mottlings of magnesian limestone in lower part. Contains thin bentonite beds. Thickness 50 to 100 feet.

Texas

Austin Chalk (Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]): Austin Chalk
Manning Formation (Phanerozoic | Cenozoic | Tertiary | Eocene): Manning Formation
Manning, Wellborn, and Cadell Formations, undivided (Phanerozoic | Cenozoic | Tertiary | Eocene): Manning, Wellborn, and Cadell Formations, undivided

Virginia

Marcellus Shale and Needmore Formation (Devonian): Marcellus Shale and Needmore Formation - Black, fissile shale; gray, non-fissile shale; Tioga metabentonite at top of Needmore
Millboro Shale and Needmore Formation (Devonian): Millboro Shale and Needmore Formation - Black, fissile shale; gray calcareous shale; Tioga metabentonite at top of Needmore.

West Virginia

Marcellus Formation and Needmore Shale, undivided (Devonian): Marcellus Formation and Needmore Shale, undivided - Marcellus Formation (part of Millboro Shale): predominantly gray-black to black thinly laminated non-calcareous pyritic shale. Contains one or more thin-bedded limestones, including the Purcell Member of Pennsylvania. Needmore Shale (part of Onesquethaw ("Onondaga") Group): predominantly dark grey or green, calcitic, mostly non-fissile shale. Gives strong "kick" on gamma ray logs. Tioga Bentonite near the top. Includes the black Beaver Dam Shale Member. Grades westward into the Huntersville Chert. Not mappable at scale of this map. Included with Dmn.
Trenton Group (Ordovician): Trenton Group - dark, crystalline, nodular, and argillaceous limestones, with some metabentonite streaks. Includes the Nealmont, Oranda, Edinburg, and the upper part of the Chambersburg Limestones of northeastern West Virginia; also the Moccasin and Eggleston Formation of Mercer and Monroe Counties.
Trenton Group and Black River Group, undivided (Ordovician): Trenton Group and Black River Group, undivided - Trenton Group: dark, crystalline, nodular, and argillaceous limestones, with some metabentonite streaks. Includes the Nealmont, Oranda, Edinburg, and the upper part of the Chambersburg Limestones of northeastern West Virginia; also the Moccasin and Eggleston Formation of Mercer and Monroe Counties. Black River Group: predominantly gray aphanitic limestones, with many bioclastic streaks; siliceous in the lower part.

Wyoming

Bear River Formation (Phanerozoic | Mesozoic | Cretaceous-Early): BEAR RIVER FORMATION--Black shale, fine-grained brown sandstone, thin limestone, and bentonite beds.
Mowry Shale (Phanerozoic | Mesozoic | Cretaceous-Early): MOWRY SHALE (AGE 94 TO 98 Ma)--Silvery-gray hard siliceous shale containing abundant fish scales and bentonite beds.
Newcastle Sandstone and Skull Creek Shale (Phanerozoic | Mesozoic | Cretaceous-Early): NEWCASTLE SANDSTONE AND SKULL CREEK SHALE. NEWCASTLE SANDSTONE--Gray sandstone and sandy shale containing some bentonite and coal. SKULL CREEK SHALE--Black soft fissile shale.
Sage Junction, Quealy, Cokeville, THomas Fork, and Smiths Formations (Phanerozoic | Mesozoic | Cretaceous-Early): SAGE JUNCTION, QUEALY, COKEVILLE, THOMAS FORK, AND SMITHS FORMATIONS. SAGE JUNCTION FORMATION--Gray and tan siltstone and sandstone. QUEALY FORMATION--Variegated mudstone and tan sandstone. COKEVILLE FORMATION--Tan sandstone, claystone, limestone, bentonite, and coal. THOMAS FORK FORMATION--Variegated mudstone and gray sandstone. SMITHS FORMATION--Ferruginous black shale and tan to brown sandstone.