STRUCTURAL INTERPRETATIONS OF THE FRONTAL OUACHITA-ARKOMA BASIN TRANSITION ZONE IN WESTERN ARKANSAS
Constraining the structural geometry and magnitude of shortening within the frontal Ouachita-Arkoma Basin transition zone is fundamental to understanding the nature of thrust propagation into foreland settings. The transition zone between the highly-deformed Ouachita frontal thrust belt and the mildly-deformed Arkoma foreland basin is exposed at the surface in western Arkansas allowing field mapping techniques to be utilized in the structural interpretation. The Ione and Barber quadrangles are located at the intersections of Logan, Scott, Franklin, and Sebastian Counties in central-western Arkansas. A structural cross section based on field mapping, 2-D depth-converted reflection seismic profiles, and electronic petrophysical well logs across these quadrangles reveals mildly deformed Pennsylvanian aged formations creating the southern limb of the broad Washburn anticline, located between the north-vergent leading edge thrust of the frontal Ouachitas and the north-vergent Washburn fault.