Provenance of Permian Delaware Mountain Group, central and southern Delaware Basin, and implications of sediment dispersal pathway near the southwestern terminus of Pangea

The Delaware Basin is located near the southwestern end of the Alleghanian–Ouachita–Marathon orogenic belt. The basin is mostly filled by Permian clastic rocks of the Delaware Mountain Group with ramp- to shelf-carbonate rimming basin edges. The Delaware Mountain Group has been well-documented as a deep-water clastic reservoir unit in the prolific Permian Basin, but its sources and related sediment dispersal pathways remain inconclusive. In this study, a total of 55 samples of the Delaware Mountain Group were collected from whole core and sidewall core from the central and southern Delaware Basin, and sandstone modal analyses and U-Pb detrital zircon geochronology were applied to constrain their potential sources. Sandstone modal analyses show that the majority of samples fall within the transitional continental source field. Age spectra of detrital zircon from five selected samples include a prominent middle Palaeozoic age cluster (~490–275 Ma), a major Neoproterozoic to early Palaeozoic age cluster (~790–510 Ma), and a series of minor age clusters of the middle to late Mesoproterozoic (~1300–920 Ma), early Mesoproterozoic (~1600–1300 Ma), late Palaeoproterozoic (~1825–1600 Ma), and Archaean and Palaeoproterozoic (> ~1825 Ma). Integrating detrital zircon data from all potential sources and coeval sandstones from the northern Delaware Basin suggests that the majority of sediment was derived from the Appalachian foreland, the Ouachita orogenic system, and the peri-Gondwanan terranes. Variation in the abundance of the different age groups reveals a provenance shift between deposition of the Brushy Canyon Formation and the Cherry and Bell Canyon Formations. To accommodate the composition, and the stratigraphic and spatial age spectral variations, we proposed that the sediment dispersal pathway includes a transcontinental fluvial system from the Appalachian orogenic belt to the east, a regional scale fluvial system from the Ouachita orogenic belt to the north and northeast, and a local, proximal fluvial system from the peri-Gondwanan terranes to the south and southeast.