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Mineral Resources > Online Spatial Data > Geology > by state > North Dakota Geology

Geologic units in Emmons county, North Dakota

Oahe Formation- River Sediment (Phanerozoic | Cenozoic | Quaternary | Holocene) at surface, covers 4 % of this area

Dark, obscurely bedded clay and silt (overbank sediment); generally overlying cross-bedded sand (channel sediment); as thick as ten meters (30 feet); on flood plains of modern streams.

Lithology: clay or mud; silt; sand

Oahe Formation- Windblown Sand (Phanerozoic | Cenozoic | Quaternary | Holocene) at surface, covers 0.9 % of this area

Well-sorted, medium sand with obscure bedding; poorly developed palesols common; as thick as 10 meters (30 feet); knobby topography consisting of inactive transverses or longitudinal dunes nearly obliterated by more recent blowouts.

Lithology: sand

Sand of the Oahe and Older Formations, Undivided (Phanerozoic | Cenozoic | Tertiary Quaternary | Pliocene Pleistocene(?) Holocene) at surface, covers 2 % of this area

Windblown sand of the Oahe Formation, as thick as 3 meters (10 feet), and sand of older formations with an undulating wind-scoured surface.

Lithology: sand

Glacial Sediment- Collapsed Glacial Sediment (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 3 % of this area

Unbedded, unsorted mixture of clay, silt, sand, and pebbles, and a few cobbles and boulders; as thick as 30 meters (100 feet)

Lithology: clay or mud; silt; sand; gravel

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

Landslides

Lithology: landslide

Coleharbor Formation- River Sediment- Uncollapsed River Sediment (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 0.6 % of this area

Moderately well sorted cross-bedded sand and plane-bedded gravel, including sediment of melt-water and other rivers; as thick as 30 meters (100 feet). Flat-bedded sediment of gently sloping plains and terraces, commonly with braided-channel scars.

Lithology: sand; gravel

Cannonball Formation (Phanerozoic | Cenozoic | Tertiary | Paleocene) at surface, covers < 0.1 % of this area

Olive-brown sand, shale, and sandstone; marine shoreline and offshore sediment; as thick as 120 meters (400 feet).

Lithology: sand; shale; sandstone

Fox Hills Formation (Phanerozoic | Mesozoic | Cretaceous-Late) at surface, covers 36 % of this area

Olive-brown sand, shale, and sandstone; marine shoreline and offshore sediment; as thick as 120 meters (400 feet).

Lithology: sand; shale; sandstone

Lacustrine Sediments (Phanerozoic | Cenozoic | Quaternary | Pleistocene [Upper Wisconsin]) at surface, covers < 0.1 % of this area

Glaciolacustrine clay and silt with minor sand and gravel. Forms flat, low-lying terrain. Includes deposits from Glacial Lake Dakota and Glacial Lake Agassiz. Thickness up to 60 ft (18m).

Lithology: clay or mud; silt; sand; gravel

Glacial Sediment- Collapsed/Draped Transition Sediments (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 14 % of this area

Unbedded, unsorted mixture of clay, silt, sand, and pebbles, and a few cobbles and boulders; as thick as 30 meters (100 feet)

Lithology: clay or mud; silt; sand; gravel

Coleharbor Formation- Offshore Sediment- Proglacial Lake Sediment (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 1 % of this area

Laminated silt and clay of glacier-dammed lakes; as thick as 60 meters (200 feet). Flat-bedded sediment of low-lying plains

Lithology: silt; clay or mud

Quaternary and Upper Tertiary Sediment, Undivided (Phanerozoic | Cenozoic | Tertiary Quaternary | Pliocene Pleistocene(?) Holocene) at surface, covers < 0.1 % of this area

Largely river sediment; includes upper Quaternary terrace, fan, and pediment gravel composed of subanglar pebbles and cobbles of locally-derived material such as sandstone, silicified wood, and concretions and Pliocene (?) to middle (?) Quaternary clay, silt, sand, and gravel composed of rounded pebbles and cobbles of quartzite and porphyry derived from the Black Hills or Rocky Mountains; as thick as 100 meters (300 feet)

Lithology: gravel

Coleharbor Formation- Offshore Sediment- Ice-Walled Lake Sediment or Collapsed Supraglacial-Lake Sediment (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 0.1 % of this area

Laminated silt and clay of glacier-dammed lakes; as thick as 60 meters (200 feet). Flat-bedded sediment elevated above surrounding area or floded sediment with hummocky topography.

Lithology: silt; clay or mud

Glacial Sediment- Collapsed Glacial Sediment (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 0.8 % of this area

Unbedded, unsorted mixture of clay, silt, sand, and pebbles, and a few cobbles and boulders; as thick as 30 meters (100 feet)

Lithology: clay or mud; silt; sand; gravel

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

Clay to boulder-size clasts with locally abundant organic material. Thickness up to 75 ft (23m).

Lithology: clay or mud; silt; sand; gravel

Outwash, Terrace (Phanerozoic | Cenozoic | Quaternary | Pleistocene [Upper Wisconsin]) at surface, covers < 0.1 % of this area

Heterogeneous clay to gravel of glaciofluvial orgin. Thickness up to 60 ft (18m)

Lithology: clay or mud; silt; sand; gravel

Coleharbor Formation- River Sediment- Collapsed River Sediment (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 5 % of this area

Moderately well sorted cross-bedded sand and plane-bedded gravel, including sediment of melt-water and other rivers; as thick as 30 meters (100 feet). Faulted and contorted supraglacial sediment with hummocky topography.

Lithology: sand; gravel

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

Dark-gray shale; marine offshore sediment; maximum outcrop thickness is a few hundred meters.

Lithology: shale

Pierre Shale (Phanerozoic | Mesozoic | Cretaceous-Late) at surface, covers < 0.1 % of this area

Blue-gray to dark-gray, fissile to blocky shale with persistent beds of bentonite, black organic shale, or light-brown chalky shale. Contains minor sandstone, conglomerate, and abundant carbonate and ferruginous concretions. Thickness 1,000-2,700 ft (305-823 m).

Lithology: shale; clay or mud; sandstone; conglomerate

Oahe Formation- Windblown Silt (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 12 % of this area

Obscurely bedded silt with paleosols; as thick as 6 meters (20 feet) where mapped. As much as 2 meters (7 feet) of windblown silt is present, but not mapped, on many level uplands southwest of the Missouri River, and less than 1 meter (3 feet) occurs at the surface throughout the state.

Lithology: silt

Fox Hills Sandstone (Phanerozoic | Mesozoic | Cretaceous-Late) at surface, covers < 0.1 % of this area

Bluish-green to green, white to dark-gray, yellow to tan, carbonaceous and iron-stained, cross-bedded, very fine- to coarse-grained, glaconitic sandstone and siltstone. Interbedded with gray and green to brown shale and silty shale. Thickness 25-400 ft (8-122 m).

Lithology: sandstone; siltstone; shale

Glacial Sediment-Glacial Sediment Draped Over Pre-existing Topography (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 4 % of this area

Unbedded, unsorted mixture of clay, silt, sand, and pebbles, and a few cobbles and boulders; as thick as 30 meters (100 feet)

Lithology: clay or mud; silt; sand; gravel

Hell Creek Formation (Phanerozoic | Mesozoic | Cretaceous-Late) at surface, covers 11 % of this area

Gray sand, silt, clay, and sandstone; river sediment; as thick as 150 meters (500 feet).

Lithology: sand; silt; clay or mud; sandstone