Evaluation of trade and interaction between Chaco Canyon and Chaco outlier sites in the American Southwest by investigating trachybasalt temper in pottery sherds

Deciphering trade and interaction in prehistory is central for archeologists to understand social, economic, political, and religious ties among groups in a particular area. Constraint on the provenance of raw materials used for manufacturing pottery vessels and their original sources is critical to these goals. In this study, trade patterns and interaction between Pueblo Bonito in Chaco Canyon and Pueblo groups in the Chuska Mountains, along with four Chaco outliers in the Four Corners area of the American Southwest, were investigated using chemical analysis of sanidine crystal inclusions identified in three groups of trachybasalt pottery temper and rocks from the Navajo volcanic field. Initial petrographic analyses were then complemented with chemical analyses using EMP and LA-ICP-MS to determine the concentrations of major and rare trace elements of the sanidine identified in trachybasalt rocks and temper sherds. Partial least squares regression on trace element concentrations from sanidine analyses for the pottery sherds and rock samples demonstrate that although the majority of sanidine tempered materials was procured from Narbona Pass in the Chuska Mountains, New Mexico, some ceramic samples were still procured from other areas of the Navajo volcanic field. The results of our provenience and geochemical study indicate that a strong relationship between Chaco Canyon and Chaco outliers should be reconsidered, and that a political and religious model of exchange-people in Chaco Canyon and Chuska Mountains controlled production and exchange systems in the San Juan Basin-should be reevaluated.