PROVENANCE CHANGES AND SEDIMENT ROUTING IN THE PENNSYLVANIAN ARKOMA FORELAND BASIN, ARKANSAS AND OKLAHOMA

The Arkoma foreland basin formed due to the Pennsylvanian Laurentia-Gondwana collision in western Arkansas and central Oklahoma. The basin succession ranges from passive margin strata overlain by deep water fan systems, that are followed by tidally influenced deltaic, paludal and fluvial deposits of shallower environments. This stratigraphic succession developed in response to rapid creation of accommodation space as the peripheral basin initially formed, followed by a decrease of subsidence rates relative to sediment supply as the collision slowed.

This study looks at provenance changes during the collision. In a transect from Arkansas to Oklahoma, Morrowan (Early Pennsylvanian) through Desmoinesian (Middle Pennsylvanian) strata were sampled for detrital zircons. Results show that most of the section has a strong Laurentian provenance signal and suggest an Appalachian source from basin-axial input systems. However, the basal part of the Desmoinesian Boggy Formation, also known as the Bluejacket Sandstone, stands out with age peaks of ~2.1 Ga and 0.55-0.7 Ga from likely Gondwanan sources. Interestingly, the Gondwanan signal disappears in sandstones higher in the Boggy Formation in Oklahoma, whereas the overlying Thurman Formation (known to be sourced from the Ouachita uplift) shows an elevated 0.55-0.7 Ga peak, but a lesser ~2.1 Ga peak.

The ~2.1 Ga signal suggests a major drainage reorganization from predominantly Laurentian sources feeding the Arkoma basin system from the northeast to a mixture of northern and southern input sources derived from Gondwana and/or peri-Gondwanan terranes. Both known West African and Amazonian basement sources for the 2.1 Ga peak can be considered but the recycling and uplift of intervening terranes like the Sabine, Suwannee or Mayan terranes are other source options being further studied with detrital zircon mixing models.