Glenhaven Member

Lithostratigraphy: Ottawa Limestone Megagroup >>Galena Group >>Decorah Subgroup >>Guttenberg Formation >>Glenhaven Member
Chronostratigraphy: Paleozoic Erathem >>Ordovician System >>Champlainian Series >>Trentonian 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 Glenhaven Member of the Guttenberg Formation (Templeton and Willman, 1963, p. 113).

Derivation

Named for Glenhaven, Grant County, Wisconsin, 2.5 miles northeast of the type section.

Type section

Type location

The type section of the Glenhaven Member is located in the same exposure as the type section for the Garnavillo Member (the roadcut of U.S. Highway 52 on the northwest side of Guttenberg (SW SW 5, 92N-2W)), where the Glenhaven is 14.8 feet thick.

Stratigraphic relationships

The Glenhaven Member is the upper member of the Guttenberg Formation. In northwestern Illinois the Glenhaven is commonly separated from the overlying Dunleith Formation by a transition zone as much as a foot thick.

Extent and thickness

The Glenhaven Member thins southward from the type area to 10-12 feet in northwestern Illinois and 7-9 feet in southwestern Illinois.

Lithology

The Glenhaven consists of tan, white-weathering, lithographic to very fine-grained limestone in beds 1-4 inches thick that are separated by layers of dark brown-red shale, generally thin but locally as much as 2 inches thick. The lower part is consistently more shaly, thinner bedded, and has wavier bedding planes than the upper part. The upper is purer and has more fossil debris and calcarenite layers. Lenses of chert are widely present in a single layer 1-2 feet above the base of the upper part and are scattered through the lower foot in the southwestern outcrops. In places in subsurface the entire formation is cherty. A bentonite bed up to 1 inch thick is widely present at the base of the Glenhaven in both northern and southern outcrop areas.

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

Stratigraphic Code	Geo Unit Designation
7760	--