Volcanic lithofacies and geochemistry of Cambrian rift-related rhyolites in the West Timbered Hills, Arbuckle Mountains, southern Oklahoma

Abstract

The Cambrian Carlton Rhyolite group forms the uppermost main unit in a major rift fill sequence in southern Oklahoma. The rhyolites crop out in the Wichita and Arbuckle Mountains. The most extensive outcrops in the latter area occur in the West Timbered Hills. My project is the first detailed volcanological and geochemical study of the West Timbered Hills rhyolites. The rhyolites there have similar A-type affinities to felsic rocks elsewhere in the southern Oklahoma rift. Seven rhyolite lava flows separated in places by sedimentary interbeds and a thick debrisflow deposit filling a paleochannel have been identified. The lava flows show a standard vertical zonation indicating they were erupted as non-explosive, simple cooling units, and the outcrop exposures may be remnants of laterally extensive flows similar to those seen in some other Atype provinces.