The characterization and significance of a MIS 5a distal tephra on mainland Australia

Lynch's Crater provides the main reference section for late Quaternary environmental change in northeast Australia. We have identified a cryptotephra horizon within late Marine Isotope Stage-5 (MIS-5) lake sediments obtained from the site. The major element geochemistry of this tephra has been compared with data from southwest Pacific sources, and our results indicate that the cryptotephra is most likely to be of Papuan origin. This is the first discovery of an aerially derived tephra in Australia that originated from outside the mainland. The Lynch's Crater tephra is potentially an important marker horizon which could be used to connect disparate palaeoarchives at a time of significant climatic and environmental change.