Niobrara Chalk

E683719
chalk formation geologic formation sedimentary rock unit

Niobrara Chalk is a Late Cretaceous marine sedimentary rock formation of soft, fossil-rich chalk and shale that is especially noted for its abundant marine reptile and fish fossils across the central United States.

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Observed surface forms (1)

Surface form Occurrences
Niobrara Formation 2

Statements (49)

Predicate Object
instanceOf chalk formation ⓘ
geologic formation ⓘ
sedimentary rock unit ⓘ
age Campanian ⓘ
Coniacian ⓘ
Santonian ⓘ
color light-colored ⓘ
contains coccoliths ⓘ
foraminifera ⓘ
microfossils ⓘ
country United States of America ⓘ
surface form: United States
depositionalEnvironment Western Interior Seaway NERFINISHED ⓘ
epicontinental sea ⓘ
discoveredBy early American geologists ⓘ
economicUse source of limestone ⓘ
fossilContent ammonites ⓘ
birds ⓘ
invertebrates ⓘ
marine turtles ⓘ
mosasaurs ⓘ
plesiosaurs ⓘ
pterosaurs ⓘ
teleost fish ⓘ
fossilPreservation exceptional vertebrate fossils ⓘ
geologicPeriod Late Cretaceous NERFINISHED ⓘ
knownFor well-preserved fish skeletons ⓘ
well-preserved mosasaur skeletons ⓘ
well-preserved pterosaur fossils ⓘ
lithology chalk ⓘ
shale ⓘ
namedFor Niobrara River NERFINISHED ⓘ
notableFor abundant fish fossils ⓘ
abundant marine reptile fossils ⓘ
outcropsIn Colorado NERFINISHED ⓘ
Kansas NERFINISHED ⓘ
Nebraska NERFINISHED ⓘ
New Mexico NERFINISHED ⓘ
South Dakota NERFINISHED ⓘ
Wyoming NERFINISHED ⓘ
overlies Carlile Shale NERFINISHED ⓘ
paleontologicalSignificance important vertebrate fossil lagerstätte ⓘ
primaryMineral calcite ⓘ
region central United States ⓘ
rockType marine sedimentary rock ⓘ
stratigraphicUnitOf Western Interior Seaway succession ⓘ
subunit Fort Hays Limestone Member NERFINISHED ⓘ
Smoky Hill Chalk Member NERFINISHED ⓘ
texture soft ⓘ
underlies Pierre Shale NERFINISHED ⓘ

Referenced by (3)

Full triples — surface form annotated when it differs from this entity's canonical label.

Gove County, Kansas → hasGeology → Niobrara Chalk ⓘ
Western Interior Basin → includesFormation → Niobrara Chalk ⓘ
this entity surface form: Niobrara Formation
Pierre Shale → overlies → Niobrara Chalk ⓘ
this entity surface form: Niobrara Formation