Establishment Member
Lithostratigraphy: Ottawa Limestone Megagroup >>Platteville Group >>Plattin Subgroup >>Mifflin Formation >>Establishment Member
Chronostratigraphy: Paleozoic Erathem >>Ordovician System >>Champlainian Series >>Blackriveran Stage
Allostratigraphy: Tippecanoe 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)
H. B. Willman and T. C. Buschbach
Name
Original description
The Establishment Member of the Mifflin Formation (Templeton and Willman, 1963, p. 82).
Derivation
Named for Establishment Creek in Ste. Genevieve County, Missouri.
Other names
History/background
Type section
Type location
The type section of the Establishment Member is an exposure in a tributary ravine just north of the village of Zell (W1/4 34, 38N-8E), where the member is 5.5 feet thick.
Type author(s)
Type status
Reference section
Reference location
Reference author(s)
Reference status
Stratigraphic relationships
Extent and thickness
The Establishment Member is 2-8 feet thick in southern Illinois. In northern Illinois it is commonly about 5 feet thick.
Lithology
The Establishment Member in southern Illinois is a green shale with thin interbeds of argillaceous, chalky limestone. The shale facies appears to be limited to a region bordering the Ozarks and is a persistent marker bed; elsewhere the member is thin-bedded, shaly, brown lithographic limestone. In the northern area, it is limestone, and is gray, dolomite mottled, argillaceous, thin bedded, and shaly. It contains a few thin beds of calcarenite.
Core(s)
Photograph(s)
Contacts
Well log characteristics
Fossils
Age and correlation
Environments of deposition
Economic importance
Remarks
References
TEMPLETON, J. S., and H. B. WILLMAN, 1963, Champlainian Series (Middle Ordovician) in Illinois: Illinois State Geological Survey Bulletin 89, 260 p.
ISGS Codes
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