Gunn Member
Lithostratigraphy: Potsdam Sandstone Megagroup >>Mt. Simon Sandstone >>Gunn Member
Chronostratigraphy: Paleozoic Erathem >>Cambrian System >>Croixan Series >>Dresbachian Stage
Allostratigraphy: Sauk 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)
T. C. Buschbach
Name
Original description
The Gunn Member of the Mt. Simon Sandstone (Templeton, 1950, p. 155).
Derivation
Named for Gunn School, De Kalb County.
Other names
History/background
Type section
Type location
The type section of the Gunn Member of the Mt. Simon Sandstone is located 2.75 miles southeast of Gunn School, De Kalb County. The member is 1648-1880 feet deep (sample set 1466) in the same boring as the Lacey Member.
Type author(s)
Type status
Reference section
Reference location
Reference author(s)
Reference status
Stratigraphic relationships
The Gunn Member overlies the Lacey Member of the Mt. Simon Sandstone.
Extent and thickness
The Gunn Member is 130-150 feet thick in the Chicago area, but elsewhere it is 71-260 feet thick.
Lithology
It is a relatively fine-grained member, but the sand ranges from fine to medium grained. A few thin conglomeratic beds are present in some areas.
Core(s)
Photograph(s)
Contacts
Well log characteristics
Fossils
Age and correlation
Environments of deposition
Economic importance
Remarks
References
TEMPLETON, J. S., 1950, Mt. Simon Sandstone in northern Illinois: Illinois Academy of Science Transactions, v. 43, p. 151-159.
ISGS Codes
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