| State | Michigan |
|---|---|
| Name | Antrim Shale |
| Geologic age | Late Devonian |
| Lithologic constituents |
Major
Sedimentary > Clastic > Mudstone > Shale > Black-shale (Bed)
Incidental
Sedimentary > Carbonate > Limestone (Bed)
|
| Comments | Secondary unit description from USGS Geologic Names lexicon (ref. MI016): The Antrim is dark gray or brown to largely black, highly carbonaceous, thinly laminated shale with meager fossil content except for profuse algal spores. Large dark brown, bituminous and pyritic limestone concretions occur in the lower Antrim and are typically from 9.6 to 1.5 m in diameter. |
| References | Milstein, Randall L. (compiler), 1987, Bedrock geology of southern Michigan: Geological Survey Division, Michigan Dept. of Natural Resources, scale 1:500,000.USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/https://ngmdb.usgs.gov/Geolex/search |
| NGMDB product | |
| Counties | Alcona - Alpena - Antrim - Benzie - Berrien - Charlevoix - Cheboygan - Emmet - Grand Traverse - Kalkaska - Leelanau - Lenawee - Macomb - Manistee - Monroe - Montmorency - Oakland - Oscoda - Otsego - Presque Isle - Saint Clair - Sanilac - Washtenaw - Wayne |