Bridgeport Anticline (New)
Part of the La Salle Anticlinorium
Location
Northwestern Lawrence County (H-8)
References
Blatchley 1913, Cady 1920, Potter 1956
Description
A large north-trending anticline in northwestern Lawrence County was documented by the authors cited above and noted as a "significant unnamed structure" by Treworgy (1981). The name Bridgeport Anticline is proposed here; the name is taken from the town of Bridgeport, which lies near the southern end of the structure.
The Bridgeport Anticline has been mapped at numerous structural levels, but it is portrayed in greatest detail on the Beech Creek ("Barlow") Limestone (fig. 19). At this level, the enclosed area is about 10 miles (16 km) long and 2 miles (3 km) wide. Closure on the Beech Creek is about 220 feet (67 m); the highest point is in the northeast quarter of Section 30, T4N, R12W. The Bridgeport Anticline lies along the crest of the newly named Charleston Monocline, near the southern end of the La Salle Anticlinorium. The monocline, which faces west-southwest, has more than 1,500 feet (450 m) of structural relief.
The Bridgeport Anticline is bordered on the east by an irregular, unnamed syncline. Northward, it is separated from the Hardinville Anticline by a saddle, the axes of the two anticlines being offset. On the south the Bridgeport Anticline plunges abruptly, and it is offset from the Lawrenceville Dome to the southeast.
Like other structures in the La Salle Anticlinorium, the Bridgeport Anticline bears evidence of both pre- and post-Pennsylvanian movement. The area of the anticline and the amount of closure (about 100 ft; 30 m) are considerably less on the Herrin Coal Member (Pennsylvanian) than on Mississippian strata (Potter 1956).
Although oil production data for the Bridgeport Anticline are not available, the so-called "Lawrence County Division," which includes pools on the Bridgeport Anticline, Lawrenceville Dome, and several smaller structures, had produced (as of December 1992) more than 413 million barrels of oil from 7,526 acres. Of the 24 pay zones, ranging from middle Pennsylvanian to the Ordovician Galena Group, the most important are the Chesterian, Cypress and Yankeetown ("Benoist") Sandstones, the Ste. Genevieve Limestone, and lower Pennsylvanian sandstones.
Figure(s)
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