Archaeological sequence diagrams and Bayesian chronological models

This paper develops directed graph representations for a class of archaeological sequence diagrams, such as the Harris Matrix, that do not include information on duration. These “stratigraphic directed graphs” differ from previous software implementations of the Harris Matrix, which employ a mix of directed graph and other data structures and algorithms. A “chronological directed graph” to represent the relationships in a Bayesian chronological model that correspond to the possibilities inherent in a sequence diagram, and an algorithm to map a stratigraphic directed graph to a chronological directed graph are proposed and illustrated with an example. These results are intended to be a proof of concept for the design of a front-end for Bayesian calibration software that is based directly on the archaeological stratigrapher's identification of contexts, observations of stratigraphic relationships, inferences concerning parts of once-whole contexts, and selection of materials for radiocarbon dating.