Culture and Ecology of Chaco Canyon and the San Juan Basin

--------Basketmaker III to Pueblo I 125from the University of Arizona's R. GwinnVivian, do so few archaeologists makeanything of it? (Stuart 2000:55)Unknown to Stuart at the time, a dune dam across theChaco Wash at its confluence with the Escavada Washmay have ensured a high water table in the canyon. (Force et a1. 2002).Stuart accepted that from the A.D. 700s on therewere two rainfall patterns in the San Juan Basin. Tothe west, a bimodal pattern provided water duringboth winter snowfalls and summer rainfaHs. To theeast and southeast, mid-sununer to late summer providedthe rains. Stuart considered Chaco to be on theboundary between these two areas; he proposed thatthe Chacoans became brokers in trade between theseareas and that pottery was the medium of exchange.Thus, during Pueblo I, the young families of farmersmoving into new areas used trade networks to shareresources. The period around A.D. 830 or 840 iswhen we see the presence of different settlement typesthat include the beginnings of great house settlementsand communities (Stuart 2000:56).Yet, as Schelberg (1982a) noted, importation ofceramics, lithics, and other nonlocal materials intoChaco Canyon was taking place as early asBasketmaker III. The ability to move from place toplace during this period, whether to hunt and gather orto establish new agricultural fields, would haveafforded kin groups the opportunity to provide theirrelatives and associates with objects obtained fromlong distances or to exchange goods and informationwith non-kin groups. At this time, we have notexamined the data in an attempt to link different roomsuites and their outdoor areas within sites to differentsources. We have not deciphered whether lithicartifacts from excavated sites indicate that differentsources may have been used as the result of visitingdifferent areas as part of the annual round or whetherthey represent changes in places where people traded.Judge's observations on obsidian and basalt imports atdifferent times and Cameron's analysis of lithicmaterials suggest shifts in the intensity and type of useof resource areas by periods. We may begin toappreciate how decisions made in times past affectedthe options available later and how Puebloan traditionsthat exist today may have started early.Recently Wilshusen and Ortman (1999), who areworking north of the San Juan River, suggested thatthe minor changes in rainfall during the late A. D.800s initiated a movement of peoples out ofsouthwestern Colorado toward the south. If accurate,the late A.D. 800s in Chaco Canyon may also haveaccommodated increasing numbers of northernneighbors, many of whom could have been related .Mobility options may have been determined throughkin groups and based on who had sufficient surplus tohandle additional relatives. The effects of shiftingpopulations and additional populations in some areas(e.g., Chaco Canyon) on social organization are justbeginning to be discussed.In summary, data from the Chaco Project helpedto clarify and establish a chronology for architecturalchanges that took place from Basketmaker III toPueblo 1. What is evident is that there were aireadysome large settlements in the canyon duringBasketmaker III, but that these settlements shifted tolower latitudes by Pueblo I, probably because ofincreasing dependence on agriculture, which requiredestablishment on better watered lands. By the mid­A.D. 800s, at least three major settlements along theconfluences of smaller washes that drain into theChaco had evidence for the establishment of largerthan-averagestructures that later grew into the greathouses for which Chaco is so well known.Models for subsistence and social organizationby Chaco Project investigators and their colleaguesvary, but all questioned the model put forth by JulianSteward (1937) that suggests a band-to-tribe organization.Instead, Schelberg (1982a) proposed that aranked social order would have been necessary inorder to monitor changes in production across theregion. Wills and Windes (1989) did not believe thata ranked society existed during the Basketmaker IIIperiod; they proposed that there was still reliance onseasonal pinon harvests and that leadership would besituational. They did propose use of two differentstorage facilities (antechambers and cists) representingshort-term and long-term facilities. They interpretedthis to indicate less-than-full-time agricultural dependence.In contrast, the macrobotanical analysis ofM. Toll (1993a) suggested that the ubiquity of comduring the Basketmaker III and Pueblo I periods wasmuch higher than during Pueblo II. If dependence on