2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 5
Presentation Time: 2:30 PM

Compression of Depositional Facies Belts as a Result of Transgression in a Narrow Sea, Chihuahua Trough, Cretaceous, West Texas

LANGFORD, Richard P., Geological Sciences, University of Texas at El Paso, 500 W. University, El Paso, TX 79968-0555 and HAMMER, Crystal L., Geological Sciences, Univ Texas - El Paso, 500 W University Ave, El Paso, TX 79968-0555, langford@geo.utep.edu

Narrow seas, such as the modern Red sea and early Atlantic seas for a unique depositional environment, with the restricted shelves, and rift associated rapid subsidence and deep basins. During the latest Jurassic through the early Late Cretaceous, the Chihuahua Trough formed a narrow sea along the present day West Texas and Mexico border. The trough is a major and poorly understood tectonic element of North American and there are conflicting theories its origin.

In the Indio Mountains of West Texas, the clastic early rift fill is the 1,500 m thick Yucca Formation. The restricted facies belts associated with the narrow sea provides a stratigraphic correlation of allows definition of 6 stratigraphic intervals. The lowest two form an alluvial fan complex. Units 3 through 5 were deposited in a coastal fluvial system and comprise a series of braided and meandering streams, floodplains and associated deltaic deposits. The top of unit 5 records an abrupt transgression that forms the primary stratigraphic marker within this interval and allows correlation between thrust sheets.

Along with the change from fluvial, to interstratified fluvial and marine strata was a compression of the lateral facies changes. The upper marine influenced intervals change from almost entirely fluvial to dominantly marine within three kilometers. This abrupt change, both stratigraphically and creates a piercing point that allows correlation of the direction and magnitude of thrusting as well as expansion of section into the deeper central Chihuahua trough.