Multi-proxy evidence of late Holocene human-induced environmental changes at Lake Pupuke, Auckland (New Zealand)

New Zealand was the last major landmass in the world to be colonised by people. Despite the short time-depth of human presence in the country there is ongoing debate about the date of earliest arrival of people that resulted in the emergence of two contrasting colonisation hypotheses: the Early hypothesis and the Short prehistory. To decide between both hypotheses we employed a range of multi-proxy investigations (geochemistry, stable isotopes and mineral magnetism) on a lacustrine sequence from Lake Pupuke, a maar lake in the city of Auckland and an area potentially among the first places in New Zealand to have been colonised by early people. The environmental history reconstructed from the multi-proxy evidence identified a clear lack of catchment disturbance from c. 2000 B.P. until several decades before the eruption of the Rangitoto volcano. The nature and abruptness of disturbance unambiguously point to anthropogenic forcings and are likely to mark the onset of prehistoric human colonisation at the site. Linear interpolation between independently dated tephrochronostratigraphic marker beds present in the sediments allowed to date this event to c. 610 cal yr B.P. This date is in compliance with the Short prehistory for this region.