An ethnographic perspective on prehistoric platform mounds of the Tonto Basin, Central Arizona

The function of prehistoric platform mounds in the American Southwest has been a subject of archaeological debate for more than 100 years. Two basic theories have been suggested: platform mounds were the residential domains of elite leaders who ruled socially complex groups, or platform mounds were nonresidential ceremonial centers used by groups of low social complexity. These theories have been based primarily on archaeological data because platform mounds were not constructed by any historic period Southwestern group. To better understand the nature of these features and the groups that used them, a cross-cultural analysis is undertaken of ethnographic or ethnohistoric platform mound-using groups from the Pacific Ocean region, South America, and the southeastern United States. Nine groups are examined in detail, and common attributes of mound-using groups are abstracted and synthesized. Insights gained through this analysis are then applied to a prehistoric settlement system in the Eastern Tonto Basin of central Arizona. This system was most intensively occupied during the Roosevelt phase (A.D. 1250-1350), when it contained five platform mounds within a 6-km stretch of the Salt River. A new model for Roosevelt phase settlement is presented that suggests that the platform mounds were constructed by two competing descent groups. Although the mounds were not residential, the groups that used them were socially complex with well-defined, institutionalized leadership. The mounds played a role in the management of irrigation and other subsistence systems and were used to integrate groups of different enculturative backgrounds and to mark descent group territory