Holocene Sea Levels and Coastal Change, South-west Viti Levu Island, Fiji

Abstract

For the first time, a sediment core spanning the entire Holocene has been analysed from Fiji. The 6 m core was obtained from the floor of an ancient coastal lagoon (palaeolagoon) adjacent to Bourewa, the site of the earliest known human settlement in this island group. The basal sediments, just above bedrock, date from 11 470 cal bp. A major transition occurs around 8000 cal bp where marine influences on palaeolagoon sedimentation increase sharply. Full shallow-water marine conditions are attained around 4630 cal bp and last until 3480 cal bp after which there is a regressive phase. The results agree with the area-specific predictions of sea level in the ICE-4G model, particularly in the timing of the highstand. In addition, the results support the ideas (a) that early human colonisation of Fiji occurred during the late Holocene regression, (b) that the first inhabitants of Bourewa utilised both nearshore marine (reefal) and brackish lagoon food sources, and (c) that the abrupt human abandonment of the area around 2500 cal bp could have been prompted by a reduction in these resources driven largely by sea-level fall.

Keywords:

• Core
• sediment analysis
• sea-level change
• Holocene
• Fiji
• lagoon (coastal)

Acknowledgements

We are grateful to the Vusama community, especially Tikiko Tavagone, for their hospitality and assistance with this project which was funded by the University of the South Pacific. Our thanks to Dr Susanne Pohler and Johnson Seeto for help at various stages of the project.