The Margaret Wash section of the Mogul fault, Pinal County, Arizona

Abstract

The Mogul fault is a strand of the Texas lineament. The Margaret Wash section of the fault is 27 air-line miles north-northeast of Tucson near the north end of the Santa Catalina Mountains0 Attitudes were measured on bedding and foliation in a long narrow belt of Pinal schist which has been in part deformed by movements on the Mogul fault. At the east end of the belt the bedding strikes northeast and dips northwest, however, at the west end of the belt bedding and gneissic foliation strike west-northwest and dip south- southwest. The writer interprets the internal structure of the Pinal schist as reflecting left lateral strike slip in a fault zone which includes the west end of the schist belt but lies to the north of the east end. The age and amount of strike slip are unknown. Later normal faulting which is probably Cenozoic cuts obliquely (more northwest) across the strike slip oriented schist. The normal fault dips steeply to the south and the maximum dip slip is probably a few hundred feet.