STRAIN PARTITIONING OF THE SOUTHERN ARKOMA BASIN IN WESTERN ARKANSAS

The Arkoma Basin is an asymmetrical peripheral foreland basin of the Pennsylvanian Ouachita Orogeny. The basin is structurally bounded by the Arbuckle Mountains of Oklahoma to the west, the Ouachita Mountains of Oklahoma and Arkansas to the south, and the Ozark Uplift of Arkansas and Missouri to the north. The basin consists of anticlines and synclines that have broader wavelengths and shallower amplitudes moving northward away from the Ouachita frontal thrust belt. This broadening sequence reflects the northward decreasing effect of contractional strain within the basin. In the Southern Arkoma Basin there are sporadic anticline and thrust pairs that occur along strike of the Ouachita frontal thrust fault. These thrust paired anticlines provide evidence at the surface that there is significant strain within the Southern Arkoma Basin.

This study intends to provide a better understanding of transition from the mildly deformed to the flat lying rocks of the Arkoma Basin. The subsurface structure as interpreted by field mapping, 2-D seismic reflection lines, and electric well log data deduces that the deformation in the subsurface is shown to be a triangle zone. Work is being done to determine the amount of compression that the triangle zone as well as the broadening anticlines and synclines have accommodated in the Southern Arkoma Basin. This work will be used to create a kinematic model of deformation and subsequently determine the strain partitioning of the Southern Arkoma Basin in Western Arkansas within the Ione and Barber Quadrangles.