Sunbury Shale

Sunbury Shale
State Michigan
Name Sunbury Shale
Geologic age Mississippian-Devonian
Lithologic constituents
Sedimentary > Clastic > Mudstone > Shale > Black-shale (Bed)
Comments Age is listed as "unassigned" on map, but is placed between Mississippian and Devonian on stratigraphic section. Secondary unit description from USGS Geologic Names lexicon (ref. MI016): Sunbury Shale is the youngest of the regionally extensive black gas shales. It is typically fissile black shale that weathers into small discoidal sharp-edged chips. Pyrite is common, particularly near the base where it separates a zone of small inarticulate brachiopods and SIPHONODELLA conodont fauna from the underlying Berea. Unit is present only in the western part of the basin. Crops out at many places along the eastern flank of the Cincinnati arch in OH and northeastern KY and ranges there from 10 to 40 ft thick. Thins to a featheredge toward the east. Overlies the Berea throughout eastern OH, WV, and northern KY, but overlies the Cleveland Member of the Ohio Shale in central KY. Grades laterally into the upper unit of the Gassaway Member of the Chattanooga Shale in south-central KY and is present only as a biostratigraphic zone in the top of the Gassaway in north-central TN.

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:

NGMDB product
Counties Alcona - Huron - Lenawee - Livingston - Macomb - Montmorency - Oakland - Oscoda - Saint Clair - Sanilac - Washtenaw - Wayne