Geologic units in Sargent county, North Dakota

Additional scientific data in this geographic area

Carlile Formation (Upper Cretaceous) at surface, covers 70 % of this area

Dark-gray shale; marine offshore sediment; as thick as 120 metres (400 feet).

Niobrara Formation (Upper Cretaceous) at surface, covers 28 % of this area

Light-brown to dark-gray calcareous shale; marine offshore sediment; as thick as 75 metres (250 feet).

Greenhorn Formation (Upper Cretaceous) at surface, covers 0.8 % of this area

Dark-gray calcareous shale; marine offshore sediment; as thick as 45 metres (150 feet).

Pierre Formation (Upper Cretaceous) at surface, covers 0.6 % of this area

Dark-gray shale; marine offshore sediment; as thick as 700 metres (2,300 feet).

Belle Fourche-Skull Creek, Undivided (Lower to Upper Cretaceous) at surface, covers 0.2 % of this area

Belle Fourche Formation (as described in Kb). Mowry Formation: medium- to dark-gray shale; marine offshore sediment; as thick as 55 metres (180 feet). Newcastle Formation: light-gray, fine- to medium-grained sandstone; marine shoreline and offshore sediment; as thick as 45 metres (150 feet). Skull Creek Formation: medium-gray to dark-gray shale; marine offshore sediment; as thick as 40 metres (140 feet).

Pierre Shale (Upper Cretaceous) 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, and light-brown chalky shale. Contains minor sandstone, conglomerate, and abundant carbonate and ferruginous concretions. Thickness up to 1,000 ft (305 m).

Niobrara Formation (Upper Cretaceous) at surface, covers < 0.1 % of this area

White to dark-gray argillaceous chalk, marl, and shale. Weathers yellow to orange. Contains thin, laterally continuous bentonite beds, chalky carbonaceous shale, minor sand, and small concretions. Thickness up to 150 ft (46 m).