The potential of tephrochronology for linking climate, environmental change and human colonisation of the South Pacific

The archipelagos of Polynesia (some 7,500 islands) in the South Pacific were the last habitable places on earth colonised by prehistoric humans. However, the timing of this colonisation has been poorly resolved across many islands, with dates varying by up to 1000 years, precluding understanding of the interplay between human, ecological and climate impacts on these pristine ecosystems. The late colonisation of many Pacific islands makes them, theoretically, the ideal location to study natural environments prior to, and subsequent to the arrival of humans, but conversely there is a paucity of palaeoenvironmental research. Very little high quality well dated palaeoenvironmental data spanning this period exists for the South Pacific. In order to begin to answer questions about the interplay between prehistoric human migration, the climate and environment, archaeological and palaeoenvironmental records need to be well dated and independently synchronised, something which is not currently possible. Existing chronologies are based on radiocarbon dating which is challenging in some of these sites especially where plant macrofossils are not available. This poster examines how volcanic ash can provide a chronological framework for dealing with these questions against a suite of new palaeoenvironmental and palaeoclimate data from Holocene lake sediment archives across the South Pacific.