Bond Formation

Lithostratigraphy: McLeansboro Group >>Bond Formation
Chronostratigraphy: Paleozoic Erathem >>Pennsylvanian Subsystem >>Missourian Series
Allostratigraphy: Absaroka 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)

M. E. Hopkins and J. A. Simon

Name

Original description

The Bond Formation of the McLeansboro Group (Kosanke et al., 1960, p. 39, 50, 70-73).

Derivation

Named for Bond County, where exposures are prominent.

Type section

Type location

Seven separate outcrops in three counties constitute the type section (NE NE NE 3, 10N-2W, Montgomery County; SE NE 28, 12N-1W, Christian County; NE NW SE 7, 8N-2W, Montgomery County; east-central 24, 6N-5W, S 1/2 7, 6N-4W, E edge 6, 7, 6N-4W, and SW NW 29, 7N-4W, Bond County).

Stratigraphic relationships

It includes all strata from the base of the Shoal Creek Limestone Member or the La Salle Limestone Member to the top of the Millersville Limestone Member or the Livingston Limestone Member (fig P-2).

Fig. P-2 -- Classification of the Pennsylvanian System. In the graphic column, blank space indicates gray shale. Named members are listed to the right of the graphic column.

Extent and thickness

The Bond Formation varies from less than 150 feet thick in eastern Illinois to over 300 feet in southeastern Illinois and averages about 250 feet (fig. P-15).

Fig. P-15 -- Thickness of the Bond Formation (based on map by K. E. Clegg).

Lithology

The Bond is characterized by a high percentage of limestone and calcareous clays and shales. The limestone members that bound the formation are the thickest and purest limestones in the Pennsylvanian System of Illinois. The upper limestone is as much as 50 feet thick and the lower is in places as much as 30 feet thick. Both are extensively quarried. In southern Illinois, south of the area of prominent development, there is no major single bench of the Millersville, and the equivalent strata are difficult to identify. Red claystones and shales are present in the Bond and are best developed in northern Illinois. Other units of the formation - gray shales, siltstones, and sandstones - are similar to those in the underlying Modesto Formation. Gray shales constitute the greatest portion of the formation, but thick channel sandstones are developed locally.

Age and correlation

The formation is also called Bond in Indiana, and it is equivalent to a portion of the Sturgis Formation in western Kentucky.

References

KOSANKE, R. M., J. A. SIMON, H. R. WANLESS, and H. B. WILLMAN, 1960, Classification of the Pennsylvanian strata of Illinois: Illinois State Geological Survey Report of Investigations 214, 84 p.

ISGS Codes

Stratigraphic Code	Geo Unit Designation
1880	b