Southeastern Section - 68th Annual Meeting - 2019

Paper No. 34-2
Presentation Time: 8:40 AM


THOMPSON, Jacob T., Department of Geosciences, Auburn University, 2050 Beard-Eaves Memorial Coliseum, Auburn, AL 36830 and HAMES, Willis, Department of Geosciences, Auburn University, Auburn, AL 36849

The Appalachian-Ouachita foreland is a vast and multifaceted foreland basin system that has been influenced by multiple tectonic events and mountain building episodes. The Ouachita-Arkoma and Black Warrior Basins of the Appalachian-Ouachita foreland preserve a thick accumulation of Paleozoic strata deposited throughout much of the Late Mississippian and Early Pennsylvanian. Complex Carboniferous drainage systems, controlled by varying global eustasy and regional tectonic activity, influenced sediment transport and deposition into the Ouachita-Arkoma and Black Warrior Basins. The evolution of these basins is investigated by detrital muscovite analysis focused on the uppermost Mississippian and lowermost Pennsylvanian in both the Ouachita-Arkoma and Black Warrior Basins. The Mississippian-Pennsylvanian boundary represents a transition from a stage of relatively slow sedimentation to a period of rapid deposition in the Early Pennsylvanian associated with the onset of continental glaciation.

40Ar/39Ar Detrital ages from the Ouachita-Arkoma Basins (n>1500) show distinct characteristics that are represented throughout samples from both the Late Mississippian and the Early Pennsylvanian. A dominant Taconic mode is constant throughout all samples from the Ouachita-Arkoma region. Two subordinate Acadian modes are often defined at ca. 370 Ma and 400 Ma. In the initial samples from the Black Warrior Basin, a younging upward progression is evident from the gradual shift from a prominent Taconic mode to Acadian and eventual Alleghanian mode higher in the section.

Significant similarities are observed between the two regions, such as the two subordinate Acadian modes at ca. 370 Ma and 400 Ma and the dominant Laurentian crustal signature. Noticeable differences in the detrital signatures is expressed by the lack of an Alleghanian mode in the Ouachita-Arkoma Basin samples and the presence of a constant Taconic peak in the Ouachitas that disappears in the higher section of the Black Warrior Basin. A few Pan-African aged grains from the Ouachita region suggests a possible secondary Gondwanan source. The dominant Laurentian crustal signature, indicated in both forelands, implies a primary Laurentian source of detritus transported by multiple complex axial drainage systems.