A Late Pleistocene record of paleoenvironmental variability in Lake George, Southeastern Australia

Abstract

Changing glacial periodicities are important events in Earth’s climatic history. However, their influence on environmental variability remains poorly studied, with existing studies on environmental variability during these events being largely restricted to continental and marine proxies in the Northern Hemisphere (Elderfield et al., 2012; Lisiecki and Raymo, 2005). This thesis presents a pilot study of core GG-1 from Lake George, Southeastern Australia, dating back to the Jaramillo Reversal event approximately 1.05 mega-annum (Ma) when glacial periodicity transitioned from 41 kilo-annum (ka) cycles to 100 ka cycles. A Late Pleistocene record of paleoenvironmental variability in Lake George is also presented based on ostracod paleoecology geochemical, a transfer function, and geochemical analysis of ostracod valves. The lake was found to record four phases: a La Niña phase, a steady state phase, an El Niño phase, and a positive Indian Ocean Dipole phase. Additionally, the findings from this thesis suggests that Mn/Ca is a potential proxy for temperature in the reconstruction of paleoenvironmental variability.