Archaeomagnetic Dates and the Hohokam Phase Sequence

Few things in Southwestern archaeology are so widely and hotly contested as the Hohokam phase sequence and chronology. Presently, no fewer than 12 different Hohokam chronologies exist and more appear to be under production. Disputes concerning the Hohokam chronology involve not only the dating of phases but also, even more basically, challenges to the integrity of the phase definitions. In the last decade, controversy has focused on three aspects of the chronology; (1) the validity and ordering of phases, (2) the argument that phases defined by pottery types overlap in time, and (3) the calibration of the phase sequence. In addition to these frequently addressed issues sufficient data presently exists to investigate the contemporaneity of phases across the Hohokam range.

The over 695 archaeomagnetic samples collected from Hohokam sites in the last decade provide a data base for evaluating most of the issues surrounding the Hohokam chronology. While a major objective of archaeological efforts in southern Arizona has been to firm up the Hohokam chronology, this problem has not been addressed effectively in the context of site specific or project specific analyses of archaeomagnetic dates. On a specific site or in a specific project the number of samples has been small, and often the samples relate to only a restricted time period within Hohokam prehistory. Further, concern remains that dates derived from a curve at least partially calibrated with Hohokam dates might be in error. When gathered together as a whole the nearly 700 samples taken in southern Arizona provide an impressive empirical base for addressing chronological concerns.

This report and the analysis on which it is based are the result of support provided by the Arizona Projects Office, U.S. Bureau of Reclamation.