The Stratigraphy and Correlation of the Bell Canyon Formation (Middle Permian, Guadalupian Series) in the Apache Mountains Near Van Horn, Texas

Michael J. Sweatt and Merlynd K. Nestell
Earth and Environmental Science, University of Texas at Arlington, Arlington, TX

The Bell Canyon Formation (Middle Permian, Guadalupian Series) has been mapped in the northwestern part of the Apache Mountains approximately 35 miles northwest of Van Horn, West Texas. At this location, exposures of Capitan reef and shelf-to-basinal strata can be correlated to similar age strata in the Guadalupe Mountains, about 50 miles to the north. The Bell Canyon Formation consists of interbedded limestone and siltstone, and several debris flows. The Castile and Rustler formations (Upper Permian, Lopingian) are also present in the mapped area and successively overly the Bell Canyon Formation. They consist of thick sequences of evaporates (dolomite, halite, and gypsum). The Bell Canyon Formation is approximately 200 meters thick within a four square mile area to the east of and bounded on the northwest by Texas FM 2185, where a series of road cuts expose several discontinuous sections of strata of the Bell Canyon, Castile, and Rustler formations. The mapped limestone units of the Bell Canyon Formation can be tentatively correlated to parts of its well known limestone members (Hegler, Pinery, Rader, McCombs, Lamar, and Reef Trail) as described in the Guadalupe Mountains by using microfossil data from conodonts, fusulinids and other foraminifers. The upper boundary of the Guadalupian Series can be traced across the area in a few meters interval of strata just below the Castile Formation. It is identified by the presence of the conodont Clarkina postbitteri hongshuiensis. Several structural trends have been mapped in the area which has a number of dislocated fault blocks. The distinctive debris flows exposed in the mapped area also have aided in the differentiation of the various faulted parts of the Bell Canyon Formation.

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas