Assessing the fidelity of palaeomagnetic records of geomagnetic reversal

Abstract

A major difficulty facing the study of geomagnetic polarity reversals lies in interpreting palaeomagnetic records of polarity transitions. These records are the sole source of information about what happens to the field as it reverses. In addition to comparison of records of the same reversal from different types of recorders to check for accuracy, we need some internal measure that can be used as a gauge of the temporal resolution provided by the data. This paper explores methods using the extent to which secular variation is recorded in the full polarity intervals bounding polarity transitions to estimate the temporal extent to which the transitional record should be interpreted. Cumulative dispersion and two autocorrelation methods are evaluated using datasets representative of different end–member palaeomagnetic records of secular variation and polarity transitions.