Louden Anticline
Location
Northeastern Fayette County and vicinity (G-6)
References
Cohee and Carter 1939, Newton 1941, Lyons 1948, Du Bois 1951, Bristol and Buschbach 1973, Buschbach and Bond 1974, Bristol and Howard 1976, Cluff and Lasemi 1980, Stevenson et al. 1981, Heigold and Oltz 1991
Description
The Louden Anticline is one of the largest oil-producing structures of the Illinois Basin. Delineated by seismic means during the oil boom of the late 1930s, the Louden Oil Field has a cumulative production of 392 million barrels. Thus, it is a truly "giant" oil field and ranks just behind Salem, the leader for Illinois in production. The name Louden Anticline, as used here, refers to the area of structural closure in the Louden Oil Field. An anticlinal nose continues more than 15 miles (24 km) south of the enclosed area. The St. James, St. James East, Wilberton, St. Paul, and Kinmundy Oil Fields are located on small domes along this unnamed anticlinal nose. Their cumulative output is about 25 million barrels of oil.
The Louden Anticline lies north of and almost in line with the Salem Anticline, which in tum aligns with the east fork of the Du Quoin Monocline. At its northern end, the Louden Anticline terminates abruptly into an area of southeastward homoclinal dip. The Mattoon Anticline is offset about 15 miles (24 km) east of the Louden trend.
The axis of the Louden Anticline is slightly sinuous, curving eastward near its northern end. Maximum closures on the Beech Creek Limestone, New Albany Group, and Galena Group (Trenton) exceed 200 feet (60 m) in T8N, R3E, Fayette County. The west limb of the Louden Anticline is considerably steeper than the east limb. Dips on the east limb are parallel to and only slightly greater than regional dip. A seismic profile (fig. 46) reveals possible normal faults at depth on the west flank of the structure (Heigold and Oltz 1991).
Du Bois (1951) showed on a series of structure maps that relief on the Louden Anticline decreases markedly upward from Chesterian through upper Pennsylvanian strata. The loss of relief reflects thinning of Pennsylvanian intervals across the anticline. Du Bois also found that some, but not all, Pennsylvanian key beds (e.g. limestones) thin, pinch out, or change facies across the structure. He concluded that uplift took place during as well as after Pennsylvanian sedimentation. Cluff and Lasemi (1980) presented evidence for uplift during early Chesterian sedimentation. A tidal channel filled with fine grained, argillaceous limestone transects the Cypress Sandstone (the main producing horizon in the Louden Field) at a right angle to the anticline. Linear bodies of Cypress Sandstone, interpreted as offshore sandbars or barrier islands, parallel the anticline and pinch out updip along its east flank. Cluff and Lasemi (1980) also recognized thinning and facies changes in pre-Cypress Chesterian strata on the anticline.
Thus, the structural style and history of development of the Louden Anticline are similar to those of other major structures in the vicinity, including the Salem Anticline, Du Quoin Monocline, and La Salle Anticlinorium.
Figure(s)
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