Arikaree Group

Consists mainly of gray, fine, loose to compact sand that has layers of hard, fine-grained dark-gray concretions which vary from few in to 15 in and often have tabular form. Includes a large amount of volcanic ash mixed in with the sand. Contains a number of channels filled with coarse conglomerate along ridge south of North Platte River. About 500 ft thick.
State Nebraska
Name Arikaree Group
Geologic age Miocene to Oligocene
Lithologic constituents
Major
Igneous > Volcanic (Pyroclastic-air fall)Includes a large amount of volcanic ash mixed in with the sand
Unconsolidated > Coarse-detrital > Sand (Bed)
Minor
Sedimentary > Clastic > Conglomerate (Bed)
Comments Includes in decending order: Monroe Creek and Sharps FMs.
References
NGMDB product
Counties Banner - Box Butte - Cherry - Dawes - Morrill - Scotts Bluff - Sheridan - Sioux