U-Pb ages of detrital zircons in lower Permian sandstone and siltstone of the Permian Basin, west Texas, USA: Evidence of dominant Gondwanan and peri-Gondwanan sediment input to Laurentia

摘要

The Permian Basin of west Texas, one of the most economically significant hydrocarbon basins in the United States, formed along the southwest margin of Laurentia in the foreland of the Ouachita-Marathon orogen during the late Paleozoic. While its stratigraphic record temporally coincides with syn- and post-orogenic Ouachita-Marathon sedimentation, sediment provenance, sediment routing and dispersal, and paleo-drainage evolution have remained controversial. This study presents more than 2000 new detrital zircon U-Pb ages from 16 samples across the Permian Basin to elucidate early Permian sediment provenance and basin-fill evolution. The data show that Wolfcampian sandstones are dominated by 950-1070 Ma and 500-700 Ma detrital zircon U-Pb ages, whereas Leonardian sandstones and siltstones are dominated by 500-700 Ma and 280-480 Ma detrital zircon U-Pb ages. Most of these age clusters are not typical Laurentian basement ages, but rather indicative of a southern Gondwanan and peri-Gondwanan sources of Mexico and Central America. This interpretation is corroborated by zircons with peri-Gondwanan and Gondwanan rimcore relationships, as well as major age components of euhedral zircons, matching Maya block basement ages. Regional comparison of these new detrital zircon results with published data from Carboniferous and Permian sedimentary rocks in various terranes of Mexico and Central America, Appalachian foreland basins, Ouachita orogenic belt, mid-continent of United States, and Fort Worth Basin (Texas), indicates that most sediment influx to the Permian Basin during the early Permian (Wolfcampian and Leonardian) was derived from basement or recycled upper Paleozoic strata associated with Gondwanan and peri-Gondwanan terranes in modern Mexico and Central America. North American basements such as the Appalachian Grenville (950-1300 Ma), Granite-Rhyolite (1300-1500 Ma), and Yavapai-Mazatzal (1600-1800 Ma) provinces, appear to have provided only minor amounts of sediment. In light of depositional age constraints, the timing of Marathon-Ouachita collision, and careful detrital zircon U-Pb age spectra comparison, the sediment provenance shift from Wolfcampian to Leonardian points to a diachronous, oblique continent-continent collision between Gondwana/peri-Gondwanan terranes and Laurentia.