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Detroit River Group

Detroit River Group
State Michigan
Name Detroit River Group
Geologic age Middle Devonian
Comments Secondary unit description from USGS Geologic Names lexicon (ref. MI016): Named the Detroit River dolomite in southeastern MI, western Ontario, CAN, and northern OH for the Detroit River. Includes (ascending) Flat Rock dolomite (40 to 150 feet thick), Anderdon limestone (40 to 50 feet thick), Amherstburg dolomite (20 feet thick), and Lucas dolomite (200 feet thick) members. Disconformably overlies Sylvania sandstone. The Detroit River is of Devonian age. Revised the Detroit River to the Detroit River group. Includes the Sylvania sandstone at base. Maximum thickness is 1,000 feet in wells in central part of Southern Peninsula of MI; outcrop thickness commonly less than 200 feet.
Primary rock type dolostone (dolomite)
Secondary rock type limestone
Other rock types sandstone
Lithologic constituents
Major
Sedimentary > Carbonate > Dolostone (Bed)
Minor
Sedimentary > Carbonate > Limestone (Bed)
Incidental
Sedimentary > Clastic > Sandstone (Bed)Revised the Detroit River to the Detroit River group. Includes the Sylvania sandstone at base.
Map references
Milstein, Randall L. (compiler), 1987, Bedrock geology of southern Michigan: Geological Survey Division, Michigan Dept. of Natural Resources, scale= 1:500,000
Unit 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 (GEOLEX)
Counties Charlevoix - Cheboygan - Emmet - Leelanau - Monroe - Presque Isle - Washtenaw - Wayne