Provenance Variations of Cretaceous Sandstones from Arkansas and Drainage Reorganization in Southern USA: Evidence from Detrital Zircon Ages

Detrital zircon (DZ) ages of Cretaceous sandstones in the United States contain critical spatial and temporal information on their sedimentary provenance and on the reorganization of drainage patterns. Herein, we report zircon U-Pb ages of sandstones from Lower Cretaceous and Upper Cretaceous formations of Arkansas. All Arkansas sandstones studied, except for those from the Upper Cretaceous Nacatoch Formation, display dominant Appalachian-Grenville DZ ages from among the Appalachian-Ouachita DZ grains that were studied. Our work shows that the sedimentary provenance of Arkansas sandstones started to change during the middle part of the Cretaceous. Notably, DZ grains from the Woodbine formation, which was deposited during the middle part of Cretaceous, show moderate contributions from Western Cordillera sources (275–55 Ma), and DZ grains from the Upper Cretaceous Nacatoch Formation exhibit dominant Western Cordillera sourcing. Our Arkansas-based DZ data suggest that the onset of DZ contribution of the Western Cordillera began at about 94 Ma, and the peak of the Western Cordillera source contribution occurred at about 73 Ma. Therefore, we can show that North American drainage reorganization with regard to Western Cordilleran DZ sourcing in Arkansas began during the time span 94–73 Ma, which is earlier than the previously reported onset of drainage reorganization with regard to Texas (i.e., 66–55 Ma).