The purpose of this study was to investigate the 4100-year sediment and geochemical record of a hydrologically-closed coastal body of water, Lake Thetis, in Western Australia. Sediment types and biota were recorded from two cores. The following climate proxies were identified: Sedimentology, Biota, and Carbon (d13C) and Oxygen (d18O) isotopic compositions. In addition, Radiocarbon dating of organic matter was used to provide a Geochronologic framework and rate of Sediment deposition.