Clay City Anticline (New Name)
Old Name: Clay City Anticlinal Belt
Location
From central Jasper County to southern Wayne County (H, I-7)
References
Bell and Cohee 1938, Bell 1943, Lowenstam 1951,Siever and Cady 1951, Du Bois and Siever 1955
Description
Bell and Cohee (1938) mapped an anticline in Richland County and informally called it the "Noble anticline." Bell (1943) and other geologists applied the name Clay City Anticlinal Belt to a larger structure that includes the Noble anticline. Although the name Noble has priority, it never achieved widespread usage and has been supplanted by Clay City. The Clay City structure is a long, sinuous, southward-plunging anticlinal nose with numerous small areas of closure. It is properly called an anticline; therefore, the name is changed here to Clay City Anticline. The term "anticlinal belt" implies a series of parallel or en echelon anticlines and is not appropriate in this case.
From the west flank of the La Salle Anticlinorium in Jasper County, the Clay City Anticline trends on a heading of 515°W through Richland and Wayne Counties. It is flanked on the west by the Bogota-Rinard Syncline and bordered on the east by an unnamed trough. Numerous stratigraphic and structural traps within the Clay City Anticline support prolific oil fields. Cumulative production from the Clay City Consolidated field is 361 million barrels.
The Clay City Anticline has been mapped at numerous levels, including the Ordovician Galena Group (Bristol and Buschbach 1973), Devonian-Mississippian New Albany Group (Bell 1943, Stevenson et al. 1981), Mississippian Karnak Limestone Member of the Ste. Genevieve Limestone (Bristol and Howard 1976), Beech Creek ("Barlow") Limestone(Bristol 1968), and Pennsylvanian Herrin Coal and West Franklin Limestone Members (Lowenstam 1951, Siever and Cady 1951, Du Bois and Siever 1955). The anticline is plotted on plate 1 as it appears at the base of the New Albany on the map of Stevenson et al. (1981).
A cross section made by Bell and Cohee (1938) demonstrates that principal deformation of the Clay City ("Noble") Anticline took place in early Pennsylvanian time, in common with most anticlinal structures in the region. A seismic reflection profile (fig. 24) shows that the anticline affects all strata down to the deepest identifiable Paleozoic reflector at the base of the Knox Group (Upper Cambrian). No faulting is detectable at the scale of the profile. The profile shows sets of strong reflectors below two-way travel times of 1.5 seconds within Precambrian basement. Such deep reflectors have appeared on many seismic lines in southern Illinois and are discussed by Pratt et al. (1989) and Heigold and Oltz (1991).
References
Figure(s)
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