Chana Member

Lithostratigraphy: Ottawa Limestone Megagroup >>Platteville Group >>Pecatonica Formation >>Chana Member
Chronostratigraphy: Paleozoic Erathem >>Ordovician System >>Champlainian Series >>Blackriveran 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 Chana Member of the Pecatonica Formation (Templeton and Willman, 1963, p. 76).

Derivation

Named for Chana, Ogle County, 9 miles east of the type section.

Type section

Type location

The type section of the Chana Member is located in a ravine (W 1/2 SE SE NE 24, 23N-9E) where it is 6.2 feet thick.

Extent and thickness

In the northern outcrop area the Chana Member is commonly less than 5 feet thick, but it reaches 20 feet in southern Illinois.

Lithology

In the northern area the Chana Member is largely brown, thick-bedded, vuggy, pure dolomite that contains disseminated sand grains and, in places, thin beds of sandstone of the St. Peter texture. The basal part commonly has slightly argillaceous or shaly beds and phosphatic pebbles. In southern Illinois it is largely pure, thick-bedded limestone.

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
8140	--