Empirical Bayes estimation for archaeological stratigraphy

Abstract

Models and algorithms are presented for the stratigraphic analysis of earth core samples collected at archaeological sites. The aim is to separate the occupation of the site into distinct periods, by dividing the earth core into well-defined blocks of uniform magnetic susceptibility. The models describe the response of detector equipment by using both a spread function and an error process, and they incorporate prior beliefs regarding the nature of the true susceptibility values. The prior parameters are estimated by using pseudolikelihood and the susceptibilities by maximum a posteriori methods via the one-step-late algorithm. These procedures are illustrated with data from synthetic and real core specimens. The new procedures prove to be far superior to other approaches, producing reconstructions which clearly show distinct periods of uniform magnetic susceptibility separated by sharp discontinuities.