SAND PROVENANCE ACROSS THE WHITE RIVER BADLANDS TOWARD THE NEBRASKA SAND HILLS

This study was conducted to test whether White River Badlands sediment is a significant component of the sand in the Nebraska Sand Hills (NSH). This investigation advances our previous work with a new statistical approach while also improving the accuracy of our data. It is predicted that dunes located in the White River Badlands (WRB) downwind of the White River Group (WRG) source rock contain sediment with a maturation signal intermediate between the source rocks and the NSH sand. Previous investigators found systematic changes in mineralogical and textural maturity in the NSH, suggesting dominant continuous downwind transport from NW to SE. In addition, these investigators suggested that Eocene and Oligocene age strata of the WRG in the WRB are a possible source of sand in the NSH. Because the WRG outcrops and WRB dune fields are to the NW of the western section of the NSH, it is possible that sand from this area may have reached the NSH. To test this hypothesis, we collected samples from terraces and floodplains of the Cheyenne and White Rivers, and their tributaries, together with sand samples from NSH and WRB dunes. We analyzed these samples using laser-induced breakdown spectroscopy (LIBS) to identify major element compositions. Our newest interpretation aims to spatially compare the NSH geochemical composition to the suspected WRG source by distance using trends along vectors in component element abundances. The hypothesis to be tested is that if White River Group sediment a source for the western NSH, then major element composition should reflect sand maturation with distance from the proposed source.