A 10,000 year long record of geomagnetic field changes, South Mavora Lake, Fiordland (New Zealand)

Abstract

A 5.5m lake sediment core from South Mavora Lake, South Island, New Zealand, has provided a geomagnetic secular variation record spanning ~11,000 to ~600 years before present, as constrained by radiocarbon dating. A stable single component magnetization resulted in reliable directional records, which are in good agreement with other regional records and reasonable agreement with records predicted by the global model CALS10k. Also predominantly clockwise looping of the geomagnetic vector corresponds with the same trends in other regional records, and possible westward drifting of the non-dipolar field. A relative palaeointensity curve was compiled through ARM normalization of the NRM intensity. This curve may eventually serve as a basis for an absolute intensity curve, and together with the directional data, provide a valuable addition in understanding secular variation in the SW Pacific.