NEODYMIUM ISOTOPE AND REE CONSTRAINTS ON PALEOZOIC SEDIMENT DISPERSAL TO THE FORT WORTH BASIN

The Fort Worth basin in east-central Texas is a foreland basin of the Ouachita orogeny, which was formed by the oblique collision of Laurentia and Gondwana during the late Paleozoic. Despite the fact that the basin is enriched with hydrocarbon resources, the sediments dispersal patterns and their influences on hydrocarbon enrichment in the basin are not well constrained. Siliciclastic grains within the late Paleozoic strata in the Fort Worth basin were proposed to be derived from local sources including the basin-bounding Ouachita orogen and Muenster uplift, or distal source of the Appalachians, or both. These hypotheses cannot be tested using detrital zircon geochronology because of the lack of sandstone and conglomerate in the Paleozoic strata in the basin, and because that the high fertility of Grenvillian zircon in sediment recycling could be misinterpreted to be Appalachian provenance. Here we study the late Paleozoic mudstone rocks in the Fort Worth basin using Nd isotope and rare-earth element (REE) compositions in order to test the hypotheses of sediment provenance. By combining our data with published detrital zircon and Nd isotope data in eastern and southern Laurentia, we will document any changes in sediment dispersal patterns to the Fort Worth basin and reconstruct paleogeography before and during the Ouachita orogeny. Our results will test the hypotheses of sediment delivery from local and distal sources during the late Paleozoic.