Assumption Coal Member
Lithostratigraphy: Kewanee Group >>Spoon Formation >>Assumption Coal Member
Chronostratigraphy: Paleozoic Erathem >>Pennsylvanian Subsystem >>Desmoinesian Series
Allostratigraphy: Absaroka Sequence
Primary source
Willman, H. B., Elwood Atherton, T. C. Buschbach, Charles Collinson, John C. Frye, M. E. Hopkins, Jerry A. Lineback, and Jack A. Simon, 1975, Handbook of Illinois Stratigraphy: Illinois State Geological Survey Bulletin 95, 261 p.
Contributing author(s)
M. E. Hopkins and J. A. Simon
Name
Original description
The Assumption Coal Member of the Spoon Formation (Cady, 1935, p. 53).
Derivation
Named for Assumption, Christian County, where the coal was mined at a depth of 1002 feet in the long-abandoned Assumption Coal and Mining Company Mine.
Other names
History/background
Type section
Type location
The type section is in the Assumption Coal and Mining Company Mine (NE NW SE 2, 12N-1E).
Type author(s)
Type status
Reference section
Reference location
Reference author(s)
Reference status
Stratigraphic relationships
Extent and thickness
The extent of the Assumption Coal has not been ascertained, but a coal at approximately this position has been encountered in a few borings scattered throughout the Illinois Basin.
Lithology
In the mine the coal was 3-4 feet thick and was commonly split into 2 benches. In part of the mine the coal was overlain by limestone correlated with the Seville Limestone, which overlies the Rock Island Coal. The two benches were within 2 feet of each other in some parts of the mine. Where the coal seam was more widely split, the limestone formed the roof of the lower bench, and the interval to the upper bench, as much as 25 feet, consisted of sandstone and carbonaceous shale. The lower bench is the Assumption Coal Member.
Core(s)
Photograph(s)
Contacts
Well log characteristics
Fossils
Age and correlation
The lower of the two benches is tentatively correlated with the Litchfield Coal of southwestern Illinois and the Rock Island (No. 1) Coal of western Illinois.
Environments of deposition
Economic importance
Remarks
References
CADY, G. H., 1935, Classification and selection of Illinois coals: Illinois State Geological Survey Bulletin 62, 354p.
ISGS Codes
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