Lusk Shale Member: Difference between revisions
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Revision as of 22:50, 27 January 2017
Lithostratigraphy: McCormick Group >>Caseyville Formation >>Lusk Shale Member
Chronostratigraphy: Paleozoic Erathem >>Pennsylvanian Subsystem >>Morrowan 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 Lusk Shale Member of the Caseyville Formation (Weller, 1940, p. 36).
Derivation
Named for Lusk Creek in Pope County.
Other names
History/background
Type section
Type location
The type section consists of exposures along the creek north of Waltersburg (12, 13S-6E).
Type author(s)
Type status
Reference section
Reference location
Reference author(s)
Reference status
Stratigraphic relationships
The Lusk Shale member is the basal unit of the Pennsylvanian System in southeastern Illinois.
Extent and thickness
The thickness of the Lusk varies from zero to over 200 feet.
Lithology
The member is composed of various amounts of silty shale, siltstone, and sandstone. Quartz pebbles are common to abundant in some sandstone units as much as 25 feet or more thick, and these units are similar to the Battery Rock and Pounds Sandstone Members. Other sandstone units as much as 50 feet thick are fine grained. The Lusk contains a few thin, unnamed, nonpersistent coal seams and a few zones with marine fossils, most of them fragmentary. In general, all the Pennsylvanian rocks in southern Illinois below the Battery Rock Sandstone are assigned to either the Lusk Shale or the Wayside Sandstone.
Core(s)
Photograph(s)
Contacts
Well log characteristics
Fossils
Age and correlation
Environments of deposition
Economic importance
Remarks
References
WELLER, J. M., 1940, Geology and oil possibilities of extreme southern Illinois: Illinois State Geological Survey Report of Investigations 71, 71 p.
ISGS Codes
Stratigraphic Code | Geo Unit Designation |
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