Arsenal Member
Lithostratigraphy: Knox Dolomite Megagroup >>Prairie du Chien Group >>Oneota Dolomite >>Arsenal Member
Chronostratigraphy: Paleozoic Erathem >>Ordovician System >>Canadian Series >>Trempealeauan 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)
H. B. Willman and T. C. Buschbach
Name
Original description
The Arsenal Member of the Oneota Dolomite (Buschbach, 1964, p. 45).
Derivation
Named for the Joliet Arsenal, Will County.
Other names
History/background
Type section
Type location
The type section for the Arsenal Member is located near Joliet Arsenal, where the type section is represented in a boring (NE NE SW 25, 34N-9E) by samples (sample set 6199) from 980-1085 feet deep.
Type author(s)
Type status
Reference section
Reference location
Reference author(s)
Reference status
Stratigraphic relationships
The Arsenal Member of the Oneota Dolomite is the lower, very cherty member.
Extent and thickness
The Arsenal Member is recognized in the northeastern quarter of the state, where it varies from 90 to almost 200 feet thick.
Lithology
It is a cherty to very cherty dolomite that is light gray with some brown or pink tinting. The dolomite is medium grained but has some coarsely crystalline zones. The chert is white or light gray, partly banded, and only rarely oolitic. Sand grains are rare, but thin shale partings are common near the base.
Core(s)
Photograph(s)
Contacts
Well log characteristics
Fossils
Age and correlation
Environments of deposition
Economic importance
Remarks
References
BUSCHBACH, T. C., 1964, Cambrian and Ordovician strata of northeastern Illinois: Illinois State Geological Survey Report of Investigations 218, 90 p.
ISGS Codes
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