A history of vegetation and climate change in northern Australia during the last 130,000 years

The monsoon is the main source of moisture for the northern third of the Australian continent. As recent climate records over the last four decades show rainfall is increasing in this region. However, the duration of these records is short, spanning less than 100 years. It is unclear if this trend is part of normal climate variability or a long term trend with important implications for agricultural development and natural hazard management. The palaeoclimate history of northern Australia has the potential to inform the likely future trend of climate. Previous investigations of past climate in this region are few in number, of short duration, and are largely limited to coastal sites which may not be regionally representative. In this thesis, the past climate record of a number of lakes/swamps located across the Northern Territory of Australia at different distances from the coast was investigated to reconstruct past changes in the extent and intensity of monsoon influence in northern Australia. The specific aims of this work were to: 1. Evaluate palaeo lake conditions across a latitudinal gradient in northern Australia during the last glacial cycle, using sedimentological, geomorphic, geochemical and isotopic approaches. 2. Develop records of the temporal patterns in hydrological activity across northern Australia, and based on this, reconstruct changes in the extent and strength of Australian Summer Monsoon (ASM) through time.