Disruption of coastal societies in the Pacific Islands from rapid sea-level fall about AD 1300: new evidence from northern Viti Levu Island, Fiji

摘要

This paper reports preliminary findings of a study in northern Viti Levu Island (Fiji) intended to test the model of the AD 1300 Event. This holds that around AD 1250-1350, during the transition between the Medieval Warm Period and the Little Ice Age, there was a rapid climate-driven sea-level fall of 70-80 cm which created a food crisis for coastal dwellers throughout the tropical Pacific Islands and led to conflict and the abandonment of open coastal settlements in favour of those in more defensible locations. Two main areas were targeted—the Ba River Valley and adjoining Vatia Peninsula (plus offshore islands)—and inland/offshore sites in defensible locations, particularly in caves, ridge-top rockshelters, and isolated hilltops, were surveyed and test excavations made. Results show that while some of these sites were established during the AD 1300 Event, most were established shortly afterwards, which is exactly what the model predicts. It is concluded that prehistoric populations in Fiji (and similar island groups) were affected by the food crisis during the AD 1300 Event and did respond in ways that profoundly and enduringly altered contemporary trajectories of societal evolution. This study has great implications for the preservation of the record of prehistoric settlement in Fiji (and other tropical Pacific Island groups) because, as a consequence of this climate-forced migration from coasts to inland/upland sites, large amounts of sediment were released from island interiors and carried to their coasts where they buried earlier settlements or redistributed their material signature. Since European arrival in such places around 150 years ago, a second wave of coastal sedimentation, largely driven by plantation agriculture development had similar effects. The current rise of sea level around Pacific Island coasts is the latest in a series of (largely human) threats to the preservation of their cultural heritage.