ABSTRACT

Subsurface Catahoula Formation samples were collected near Marco, Louisiana by the U.S. Army Corps of Engineers for the Red River Lock and Dam No. 3 investigation. Core samples were classified in the field by geologists and later analyzed in the lab for grain size, sorting and mineralogy. Compiled cross sections based on core and electric log data portray local stratigraphic facies of interbedded sands, sandy claystones, and claystones with occasional lignites. Paleobotanic analysis of leaf imprints (Myrica sp. and Iva sp.) indicate a subtropical, coastal/deltaic environment of deposition. Scanning electron microscope, petrographic and X-ray diffraction analyses conducted on representative samples revealed major amounts of montmorillonite, kaolinite, illite, and cristobalite. These findings support the concept of rapid burial of coastal/deltaic sand and clay bodies derived from eroded continental material and occasional volcanic sources.