PLANT WAX BIOMARKERS IN LATE NEOGENE PALEOSOLS AS ARCHIVES OF GREAT PLAINS VEGETATION
Here we explore plant wax biomarkers from late Neogene sediments of the Meade Basin in southwest Kansas as a tool for reconstructing vegetation in the Great Plains over the last ca.10 million years. Critical steps for generating reliable data for paleoecological reconstructions include establishing sampling protocols that prevent potential contamination from modern plant waxes and assessing biomarker preservation prior to isotopic analysis. Plant wax molecular distributions from Meade Basin sediments indicate excellent biomarker preservation and concentrations sufficient for compound specific isotope analysis in nearly all samples. Carbon isotope data indicate a wide range of environments from C3‑dominated (>75% C3 vegetation) to C4‑dominated landscapes with an overall trend towards more C4 vegetation from the late Miocene to present. Plant wax isotope data from the C31 n‑alkane show the best agreement with co-existing carbon isotope data from carbonate samples taken from the same stratigraphic horizon. Plant wax isotope data from terrestrial sediments in the Meade Basin illustrate the potential for biomarkers in reconstructing local vegetation from terrestrial sediments, particularly from paleosols where pedogenic carbonates are absent.