ABSTRACT
The Ste. Genevieve fault zone extends eastward from Missouri across the Mississippi River into Jackson County, Illinois, about 75 mi (120 km) southeast of St. Louis. Outcrop studies have dated movement along portions of the zone as pre-Middle Devonian, post-Mississippian, and post-Pennsylvanian. Present displacement is down to the north and east with throw ranging up to 3,000 ft (915 m). However, pre-Middle Devonian movement was down to the south and west.
The present upthrown block shows no evidence of vertical movement during the Cambrian and Ordovician. Nor is there any indication that the fault zone was part of the northern border of the Reelfoot basin, where earliest Paleozoic sediments infilled an aulacogen at the northern end of the Mississippi embayment.
