Archaeomagnetic Dating and the Bonito Phase Chronology

A method is presented for the reanalysis of a large archaeomagnetic data set from the Chaco Canyon region in northwest New Mexico, U.S.A., for which virtual geomagnetic pole (VGP) position data have not been reported. Reanalysis based upon the archaeomagnetic curve model SWCV590-CSU resulted in large age ranges. The level of precision reported in the past was not reproducible given available data. The consistent lateness of archaeomagnetic dates reported by Robert DuBois is accounted for by recent research that has altered segments of the archaeomagnetic curve. Archaeomagnetic and tree-ring data from the Late Bonito phase Chacoan community of Bis sa'ani are used to contrast the results of two different methods of interpretation. Factors that have influenced the composition of the archaeomagnetic data base are identified. Recommendations are made for reporting archaeomagnetic dates.