Niobrara Formation (NEKn;0)

Niobrara Formation

Argillaceous chalk, limestone and shale. Chalk is medium gray to white, interbedded with thin layers of chalky shale; contains many fossil clams, oysters, and formanifera. Limestone is light gray to medium gray and yellowish gray, interbedded with medium-gray chalky shale; also contains fossil clams, oysters, and formanifera. Bedding plans commonly marked by thin layers of gypsum and locally a thin bed of red flint occurs at top of unit. Approx. max thickness 570 ft.

State	Nebraska
Name	Niobrara Formation
Geologic age	Late Cretaceous
Lithologic constituents	Major Sedimentary > Carbonate > Limestone (Bed)Chalk= Limestone Sedimentary > Clastic > Mudstone > Shale (Bed)
Comments	Colorado Group
References	Burchett, R.R., 1986, Geologic Bedrock Map of Nebraska: Nebraska Geological Survey. Scale 1:1 million. Burchett, R.R., Dreeszen, V.H., Souders, V.L., and Prichard, G.E., 1988, Bedrock Geologic Map Showing the Bedrock Surface in the Nebraska Part of the Sioux City 1x2 Quad.: USGS Map I-1879. Scale 1:250 K. https://pubs.er.usgs.gov/publication/i1879
NGMDB product	NGMDB product page for 39227
Counties	Adams - Boyd - Cedar - Clay - Colfax - Dawes - Dixon - Fillmore - Franklin - Frontier - Furnas - Gosper - Hall - Hamilton - Harlan - Howard - Kearney - Knox - Madison - Merrick - Nance - Nuckolls - Pierce - Platte - Polk - Red Willow - Sheridan - Stanton - Wayne - Webster - York

Niobrara Formation

Burchett, R.R., 1986, Geologic Bedrock Map of Nebraska: Nebraska Geological Survey. Scale 1:1 million.

Burchett, R.R., Dreeszen, V.H., Souders, V.L., and Prichard, G.E., 1988, Bedrock Geologic Map Showing the Bedrock Surface in the Nebraska Part of the Sioux City 1x2 Quad.: USGS Map I-1879. Scale 1:250 K.