Abstract
<jats:title>ABSTRACT</jats:title> <jats:p>Subsidence and lithostratigraphic trends suggest that three separate clastic wedges derived from the northeast (southern Appalachian; Pennington-Lee), southeast (Cahaba), and southwest (Black Warrior) merged into a connected foreland system by Early Pennsylvanian time at the juncture between the Alleghanian and Ouachita thrust belts. To investigate sediment provenance, we used detrital zircon U-Pb geochronologic data from uppermost Mississippian and Lower Pennsylvanian strata in the southern Appalachian foreland basin, the Cahaba synclinorium, and the Black Warrior foreland basin. Results show that the Pottsville Formation, as well as the underlying Parkwood and Pennington-Parkwood formations, exhibit similar age spectra and are defined by a dominant Grenville (1250–900 Ma) age mode alongside smaller Appalachian (490–330 Ma), Granite-Rhyolite (1550–1300 Ma), Yavapai-Mazatzal (1800–1600 Ma), Trans-Hudson (2000–1800 Ma), and Wyoming-Superior (&gt;2500 Ma) age modes. The overall homogeneity of age spectra requires that strata from these distinct depocenters either received sediment from a similar source terrane or that detrital zircon geochronology provides indistinguishable signatures for Pennsylvanian strata in eastern North America. Proportional differences in age spectra associated with an increased abundance in Granite-Rhyolite or Yavapai-Mazatzal age modes do differentiate some of our samples, which we interpret to be associated with either transverse or longitudinal sediment-routing systems, relative to the structural development of the southern Appalachians. We suggest that a combination of Cambrian through Devonian strata currently within the Alleghanian thrust belt represents the source region for Lower Pennsylvanian strata at the juncture of the Ouachita and Alleghanian thrust belts, requiring unique routing systems for each depocenter. This study highlights the difficulty of using detrital zircon U-Pb geochronology for sediment provenance investigations of late Paleozoic units in eastern North America.</jats:p>