ABSTRACT

Structural and lithological analysis of four exposures along the South Muskogee Fault indicates that a section of this fault is incorrectly located on the geologic maps in portions of Muskogee and Cherokee Counties in northeastern Oklahoma. The South Muskogee Fault is a normal fault, dipping to the north, bringing Pennsylvanian-aged rocks in contact with Mississippian strata. Drag folds are present in the area and are used, in conjunction with lithological similarities, to determine the true location of the fault. Drag-fold geometry shows that drag along the footwall of a normal fault will increase in dip as it approaches the fault plane. Structural attitudes of these four exposures, located on the hanging wall side of the fault by present maps, show an increase in dip toward the north, indicating that the four exposures are located on the footwall side of the fault. These measurements indicate that the fault is incorrectly located on the present geologic maps and should be relocated at least 0.3 to 0.5 miles (0.47 to 0.8 km) to the north of its present position.