The magnetisation of some New Zealand pleistocene varved glacial sediments

Abstract

A palaeomagnetic survey in order to determine the possibility of obtaining the secular variation of the earth's field in the Pleistocene from New Zealand's glacial lake sequences, has been carried out. The sediments from Bryant's Gully, Rakaia Valley are found to possess consistent and stable magnetisation directions, and the scatter is such that good statistical accuracy of the mean directions of magnetisation is easily attainable. The differences in the means of beds separated in time has been attributed to a secular variation of the field of the same order as at present. It has also been shown that wide variations in intensity of magnetisation are likely to be found in sediments from differing localities. Fairly large variations between beds and smaller within-bed variations also occur.