CHACOAN AND POST-CHACO OCCUPATIONS IN THE MIDDLE SAN JUAN REGION: CHANGES IN SETTLEMENT AND POPULATION

Abstract

The Middle San Juan region occupies a critical location between Chaco Canyon to the south and Mesa Verde to the north. Site-settlement analysis and demographic reconstruction reveal continuous occupation across the Pueblo II–III transition and steady population growth for 200 years prior to regional depopulation in the late A.D. 1200s. These findings challenge previous research which postulated two distinct occupations: Chacoan domination during the Pueblo II period, followed by abandonment and subsequent immigration from Mesa Verde comprising reoccupation during the Pueblo III period. Our research indicates that late Pueblo II Chacoan colonization at Salmon Pueblo (along the San Juan River) and Aztec Ruins (on the Animas River) occurred abruptly in areas with little previous settlement. In contrast, much smaller Chacoan outliers were built within dense, extant communities in the La Plata Valley and lower San Juan River between A.D. 1075 and 1125. Instead of abandonment coinciding with the region-wide drought during the mid-1100s, we argue that demographic trends and other archaeological evidence indicate sustained population growth coinciding with changes in social identity during the post-Chaco era. Depopulation did not occur until the late thirteenth century when a similar process affected the entire Four Corners area.