A bootstrap algorithm for deriving the archeomagnetic field intensity variation curve in the Middle East over the past 4 millennia BC

Abstract

Recent compilations of archeomagnetic intensity data have shown the existence of outliers. Acknowledging this problem, we propose a new way of generating and studying the uniqueness of regional archeomagnetic master curves bypassing the need to assume a normal data error distribution. Our approach lessens the weight of outliers by applying an iteratively re-weighted least-squares method combined with a bootstrap algorithm. Given a particular set of archeomagnetic data associated with experimental and dating uncertainties, we produce an ensemble of curves that are designed to sample the conditional probability distribution of the true master curve. Using this technique, we propose an archeointensity master curve with its probability density for the Middle East region that covers the past four millennia BC. © 2010 by the American Geophysical Union.