Washburne Anticline Delta Structure: Model Based on Integration of Thematic Mapper, Seismic, and Well-Log Data

R. L. Dodge, M. L. Keeling, D. H. Cassiani

The Washburne anticline located in western Arkansas is a prominent, thrust-related structure at the leading edge of the Ouachita orogenic belt. Previously interpreted as a complexly thrust-faulted anticline, the feature has been reinterpreted as a delta or triangle structure based on integration of surface mapping from thematic mapper (TM) data with subsurface interpretation of seismic and well-log cross sections.

The northern limb of the Washburne anticline consists of a relatively unfaulted, steeply north-dipping sheet above a major north-dipping backthrust. The southern limb consists of several steeply south-dipping imbricate thrust sheets that form a duplex zone in the center of the delta structure. Seismic and well-log interpretations indicate the presence of the imbrication in the duplex zone, but poor seismic resolution within the structure made interpretation of the back thrust difficult. Surface mapping from TM imagery indicates the presence of the back thrust and the extent and geometry of the delta structure. Imbricate thrust sheets and horses also crop out, and their geometry is a guide to interpretation of subsurface data sets.

The new model of the Washburne anticline as a delta structure has aided in subsurface-data analysis and has resulted in a better understanding of trap geometry and distribution. This study also demonstrates the application of detailed surface mapping from satellite remote-sensing data to prospect-scale analysis.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.