Rheic Ocean closure recorded in the deepwater Atoka Formation, Ouachita Mountains: Integrate sedimentology and provenance assessment

Bharat Banjade
The University of Tulsa, Department of Geoscience Tulsa, Oklahoma, USA 74104
[email protected]

Tectonostratigraphic evolution of the Ouachita trough is the result of the closure of the Rheic Ocean, which separated Laurassia from Gondwana for most of the Paleozoic Era. The mid-Carboniferous deepwater Atoka Formation records the final stages of ocean closure that in turn was followed by orogenic suturing (Ouachita fold-thrust belt) to form Pangea. Despite decades of study and proposed contradictory plate tectonic models, this major Earth history event is not well understood along the southern margin of Laurentia. For the resolution of the problem, three hypothetical plate tectonic models are considered to explain final closure of the Rheic Ocean: 1) subduction of oceanic lithosphere beneath Laurentia; 2) oceanic lithosphere subduction beneath Gondwana continental crust; and 3) oceanic lithosphere subduction involving island arc complex.

This research includes both the field work and lab work to test the proposed models. Field work will be conducted in two parts of the Ouachita fold-thrust belt: the frontal zone of Ouachita (northern part of Ouachita, proximal to Laurentia), and the southern fold-thrust belt with exposures in the Boktukola Mountains and the Athens Plateau areas (distal to Laurentia and proximal to any Gondwana terranes). Field work includes detailed stratigraphic section measurement, and sample collection, of both sandstone and mudstone, with reference to lithofacies and paleocurrent indicators. The lab work will includes study of thin-sections, bulk rock geochemistry, trace element geochemistry, and heavy minerals. The result of the research will give the proximity and type of provenance terranes, changes in sediment source, and basin evolution through time.

AAPG Search and Discovery Article #90157©2012 AAPG Foundation 2012 Grants-in-Aid Projects