Analysis of palaeomagnetic inclination data

Abstract

The analysis of palaeomagnetic data where only inclinations are available is considered. Maximum likelihood estimates for the mean inclination I0 and Fisher's precision parameter k are derived. It is shown that they are in all cases biased although the bias is small for low inclinations. The case of steep inclinations and small values of k is examined and it is shown that in this region I0 and k are not separable as distinct variables, because the lack of declination information in this region leads to fundamental ambiguities. Unbiased estimates for I0 and (1/k) are derived for the case where the portion of the distribution folded about the vertical is insubstantial. A worked example of the method, with calculation of confidence limits, is appended.