Chalfin Member
Lithostratigraphy: Mammoth Cave Limestone Megagroup >>Salem Limestone >>Chalfin Member
Chronostratigraphy: Paleozoic Erathem >>Mississippian Subsystem >>Valmeyeran Series
Allostratigraphy: Kaskaskia 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)
Elwood Atherton, Charles Collinson, and Jerry A. Lineback
Name
Original description
The Chalfin Member of the Salem Limestone (Baxter, 1960a, p. 24-27).
Derivation
Named for the village of Chalfin Bridge, Monroe County.
Other names
History/background
Type section
Type location
The type section of the Chalfin Member is in the Mississippi River bluffs 1 mile southwest of the village of Chalfin Bridge (NE SW 7, 4S-10W), where the member is 39.5 feet thick.
Type author(s)
Type status
Reference section
Reference location
Reference author(s)
Reference status
Stratigraphic relationships
Extent and thickness
The Chalfin is 26-57 feet thick in the outcrop area.
Lithology
The Chalfin consists of varying thicknesses of fine-grained limestone; fine- to medium-grained, fossiliferous, locally oolitic limestone; and semilithographic limestone, some of it brecciated. The lower 10 feet is predominantly a calcarenite composed of bryozoan detritus, crinoid columnals, microcrystalline pellets, and a few oolites.
Core(s)
Photograph(s)
Contacts
Well log characteristics
Fossils
Eoendothyranopsis group pressus-rarus, Koninckopora sahariensis, K. inflata, Septabrunsiina, and profuse Calcisphaera characterize the Chalfin.
Age and correlation
Environments of deposition
Economic importance
Remarks
References
BAXTER, J. W., 1960a, Salem Limestone in southwestern Illinois: Illinois State Geological Survey Circular 284, 32
ISGS Codes
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