Coleraine Formation

Conglomerate, lignite, sandstone, and shale; shallow marine and non-marine. Late Cenomanian age is inferred. Despite exposures in mines on the Mesabi Iron Range, the position of much of the unit contact is highly speculative.
State Minnesota
Name Coleraine Formation
Geologic age Late Cenomanian
Lithologic constituents
Sedimentary > Clastic > Conglomerate (Bed)
Sedimentary > Coal > Lignite (Bed)
Sedimentary > Clastic > Sandstone (Bed)
Sedimentary > Clastic > Mudstone > Shale (Bed)

Jirsa, Mark A., Boerboom, Terrence J., Chandler, Val W., Mossler, John H., Runkel, Anthony C., and Setterholm, Dale R., 2011, S-21 Geologic Map of Minnesota-Bedrock Geology; Minnesota Geological Survey, State Map Series S-21. Scale 1:500,000.

NGMDB product
Counties Aitkin - Cass - Crow Wing - Itasca - Saint Louis