Historical:Owl Creek Formation

Lithostratigraphy: Embayment Megagroup >>Owl Creek Formation
Chronostratigraphy: Mesozoic Erathem >>Cretaceous System >>Gulfian Series

Authors

H. B. Willman and John C. Frye

Name Origin

The Owl Creek Formation (Hilgard, 1860) (fig. K-2), named for exposures along Owl Creek, 3 miles northeast of Ripley, Tippah County, Mississippi, is the uppermost Cretaceous Formation in southern Illinois.

Fig. K-2 -- Classification of the Cretaceous System

Extent and Thickness

The Owl Creek Formation is exposed in Illinois only in Pulaski County along the Ohio River near U.S. Dam 53 (SE NW NE 13, 15S-1E) and along the Cache River near Unity (NE 7, S 1/2 6, 16S-1W) (Pryor and Ross, 1962). It is 0-10 feet thick.

Stratigraphic Position

The Owl Creek overlies the McNairy Formation Formation conformably. A weathered zone at its top, marked by concentrations of hematitic nodules and a sharp upper contact, indicates an unconformity that separates the Owl Creek from the overlying Tertiary Clayton Formation.

Description

It consists of glauconitic, very micaceous, sandy, silty clay and silt.

Depositional Environment

The Owl Creek indicates a brief advance of the sea over the McNairy delta.

References

HILGARD, E. W., 1860, Report on the geology and agriculture of the State of Mississippi: Jackson, Mississippi, p.79. 84-91, 102.
PRYOR, W. A., and C. A. ROSS, 1962, Geology of the Illinois parts of the Cairo, La Center, and Thebes Quadrangles: Illinois State Geological Survey Circular 332, 39 p.

ISGS Codes

Stratigraphic Code	Geo Unit Designation
1380	Ko