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Geological Formation

Niobrara Formation

Named Rock Formations and Groups

The Niobrara Formation, also called the Niobrara Chalk, is a geologic formation across the Great Plains of the United States and Canada, deposited between about 87 and 82 million years ago during the Coniacian, Santonian and Campanian stages of the Late Cretaceous. It consists of two members, the Smoky Hill Chalk overlying the Fort Hays Limestone, composed mainly of chalk with some shale, formed from the accumulated coccoliths of microorganisms that lived in the Western Interior Seaway, the shallow inland sea that divided North America for much of the Cretaceous. The formation's type locality is the Niobrara River in Knox County, in northeastern Nebraska.

Connections

Associated With

Chalk, Materials
Source Niobrara Formation (Wikipedia)
Cretaceous, Eras
Source Niobrara Formation (Wikipedia)
Limestone, Materials
Source Niobrara Formation (Wikipedia)

Caused By

Sedimentation, Processes
Source Niobrara Formation (Wikipedia)

In Discipline

Stratigraphy, Disciplines
Source Niobrara Formation (Wikipedia)
In the Other Atlases

Found In

Canada

Also in Geography Atlas: where this subject is found.

United States

Also in Geography Atlas: where this subject is found.

Sources
Niobrara Formation (Wikipedia)
  • Associated With: Cretaceous, Lead paragraph
    The Niobrara Formation , also called the Niobrara Chalk, is a geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the Late Cretaceous.
  • Associated With: Limestone, Lead paragraph
    It is composed of two structural units, the Smoky Hill Chalk Member overlying the Fort Hays Limestone Member.
  • Associated With: Chalk, Lead paragraph
    It is composed of two structural units, the Smoky Hill Chalk Member overlying the Fort Hays Limestone Member.
  • Associated With: Cretaceous, Lead, age Cretaceous
    The Niobrara Formation , also called the Niobrara Chalk, is a geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the Late Cretaceous.
  • Associated With: Chalk, Lead, rock Chalk
    The Niobrara Formation , also called the Niobrara Chalk, is a geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the Late Cretaceous.
  • Associated With: Limestone, Lead, rock Limestone
    It is composed of two structural units, the Smoky Hill Chalk Member overlying the Fort Hays Limestone Member.
  • In Discipline: Stratigraphy, Lead paragraph
    The Niobrara Formation , also called the Niobrara Chalk, is a geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the Late Cretaceous
  • Caused By: Sedimentation, Lead paragraph
    The Niobrara Formation , also called the Niobrara Chalk, is a geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the Late Cretaceous
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