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Galen W. Miller1, Kevin J. Smart1
(1) University of Oklahoma, Norman, OK

Abstract: The Potato Hills revisited: Exploration potential aided by mesoscale structural studies

The Potato Hills are a roughly elliptical exposure of Ordovician to Mississippian rocks in the Central Ouachita Mountains of southeastern Oklahoma. The Potato Hills have been variously interpreted, both as a structural window through an upper folded thrust sheet and as pop-up block between oppositely-vergent thrusts (i.e., forethrust and backthrust). Ongoing exploration interests in the Ouachita Mountains, and particularly deeper structures in the Potato Hills, suggests that a better understanding of the complex deformation history is needed. This study focuses on a detailed mesoscale analysis and 1:24000 scale geologic mapping of the Potato Hills with the goal of clarifying the structural interpretation and integrating this into the overall tectonic development of the Ouachitas.

Preliminary field mapping confirms the presence of numerous upright to steeply-inclined, subhorizontal, tight to isoclinal folds that span a range of scales (from a few meters to 100’s of meters). Many folds display straight limbs and small angular hinges (kink folds) that are parasitic with respect to larger folds. The structural fabric is nearly east-west (strike varies from 075 to 080), although local variations exist, particularly near the western edge of the Potato Hills where the structures plunge more steeply to the west. Although the overall structural interpretation (window vs. pop-up) is still unclear, the strongly-plunging folds near the western edge of the Potato Hills, lends support to the window interpretation.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana