Late Devonian shale deposition based on known and predicted occurrence of Foerstia in Michigan basin
The fossil Foerstia (Protosalvinia) marks a time zone within Late Devonian shale sequences in the eastern US. Its recent discovery in Michigan has led to more accurate correlations among the three large eastern basins. Subdivisions of the Devonian-Mississippi shale sequence in Michigan based on gamma-ray correlations reveal an idealized black shale geometry common to other eastern black shales, such as the Sunbury of Michigan and Ohio, the Clegg Creek of Indiana, the Dunkirk of Pennsylvania and New York, and the lower Huron of Ohio and West Virginia. In Michigan, Foerstia occurs at a stratigraphic position postulated to mark a major change in depositional conditions and source areas. This position strengthens the physical and paleontologic evidence for a formal division of the Antrim. Isopach maps of the shale sequence above and below Foerstia show a relatively uniform and continuous black shale deposit (units 1A, 1B, and 1C) below Foerstia. This deposit is unlike the wedge of sediment found above Foerstia, which is composed of a western facies (Ellsworth) and an eastern facies (upper Antrim) that should be combined in a single stratigraphic unit conforming to Forgotson's concept of a format.
- Research Organization:
- R.D. Matthews, Inc., Chicago, IL
- OSTI ID:
- 7053592
- Report Number(s):
- CONF-8610158-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 70:8; Conference: AAPG Eastern section meeting, Ann Arbor, MI, USA, 1 Oct 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BLACK SHALES
DEPOSITION
MICHIGAN
SEDIMENTARY BASINS
DEVONIAN PERIOD
GEOLOGIC FORMATIONS
MISSISSIPPIAN PERIOD
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CHATTANOOGA FORMATION
ENERGY SOURCES
FEDERAL REGION V
FOSSIL FUELS
FUELS
GEOLOGIC AGES
GEOLOGIC STRUCTURES
MATERIALS
NORTH AMERICA
OIL SHALES
PALEOZOIC ERA
USA
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Geology
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