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

Geologic units in Steele county, North Dakota

Oahe Formation- Pond Sediment (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers < 0.1 % of this area

Dark, obscurely bedded clay and silt; typically a few meters thick; in modern ephemeral ponds.

Lithology: clay or mud; silt

Glacial Sediment- Collapsed/Draped Transition Sediments (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 18 % 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- River Sediment- Uncollapsed River Sediment (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 0.7 % 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

Oahe Formation- River Sediment (Phanerozoic | Cenozoic | Quaternary | Holocene) at surface, covers 14 % 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

Glacial Sediment- Collapsed Glacial Sediment (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 36 % 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

Glacial Sediment- Collapsed Glacial Sediment (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 20 % 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

Glacial Sediment- Glacial Sediment Draped Over Pre-existing Topography (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 1 % 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

Glacial Sediment- Wave-Eroded Glacial Sediment (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene) at surface, covers 10 % 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

Pierre Formation (Phanerozoic | Mesozoic | Cretaceous-Late) at surface, covers 0.5 % of this area

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

Lithology: shale