Abstract: A Regional Perspective on the Ouachita Trend and Related Foreland Structures
Randy G. Keller
The Ouachita trend represents a major Paleozoic orogenic belt which is only exposed in the Ouachita Mountains and the Marathon region of West Texas. Despite its location in what is commonly viewed as "oil country," the structure, evolution, and petroleum potential of this significant geologic feature is poorly known. Because of the scarcity of detailed studies and deep drilling, some insight can be gained from the analysis of regional geophysical data such as gravity, magnetic, and retraction surveys. The UTEP geophysics group has been engaged in studies of the Ouachita trend for many years, and we continue to enlarge our database in the area. The integration of seismic retraction data with gravity and drilling data has led to a surprising picture of the early Paleozoic p ssive continental margin which developed prior to the Ouachita orogeny. This margin appears to be largely intact beneath thrust sheets that are indicative of thin-skinned tectonics. It is thus a very viable deep exploration target. The Ouachita thrust sheets appear to overlap this margin to varying degrees along the trend. About half of the Arkoma basin is overthrusted whereas an entire basin may be overthrusted near San Antonio. A deep wildcat presently being drilled west of San Antonio appears to be testing this hypothesis. Most of the structural framework of the adjacent foreland areas is due either to the early Paleozoic rifting which formed the Ouachita margin or the late Paleozoic Ouachita orogeny. The sub-Ellenberger units which resulted have yet to be adequately tested in many ar as.
AAPG Search and Discovery Article #90960©1995 AAPG Southwest Section Meeting, Dallas, Texas