9 The Primary Architecture of the Chacoan Culture A Cosmological Expression Anna Sofaer TUDIES BY THE SOLSTICE PROJECT indicate that the solar-and-lunar regional pattern that is symmetri- Smajor buildings of the ancient Chacoan culture cally ordered about Chaco Canyon’s central com- of New Mexico contain solar and lunar cosmology plex of large ceremonial buildings (Sofaer, Sinclair, in three separate articulations: their orientations, and Williams 1987). These findings suggest a cos- internal geometry, and geographic interrelation- mological purpose motivating and directing the ships were developed in relationship to the cycles construction and the orientation, internal geome- of the sun and moon. try, and interrelationships of the primary Chacoan From approximately 900 to 1130, the Chacoan architecture. society, a prehistoric Pueblo culture, constructed This essay presents a synthesis of the results of numerous multistoried buildings and extensive several studies by the Solstice Project between 1984 roads throughout the eighty thousand square kilo- and 1997 and hypotheses about the conceptual meters of the arid San Juan Basin of northwestern and symbolic meaning of the Chacoan astronomi- New Mexico (Cordell 1984; Lekson et al. 1988; cal achievements. For certain details of Solstice Pro- Marshall et al. 1979; Vivian 1990) (Figure 9.1). ject studies, the reader is referred to several earlier Evidence suggests that expressions of the Chacoan published papers.1 culture extended over a region two to four times the size of the San Juan Basin (Fowler and Stein Background 1992; Lekson et al. 1988). Chaco Canyon, where most of the largest buildings were constructed, was The Chacoan buildings were of a huge scale and the center of the culture (Figures 9.2 and 9.3). The “spectacular appearance” (Neitzel 1989). The canyon is located close to the center of the high buildings typically had large public plazas and desert of the San Juan Basin. elaborate “architectural earthworks” that formed Twelve of the fourteen major Chacoan buildings road entries (Stein and McKenna 1988). The major are oriented to the midpoints and extremes of the Chacoan buildings, the subject of the Solstice Pro- solar and lunar cycles (Sofaer, Sinclair, and Don- ject’s studies (Figures 9.3 and 9.4), are noted in ahue 1991). The eleven rectangular major Chacoan particular for their massive core veneer masonry. buildings have internal geometry that corresponds They were up to four stories high and contained as to the relationship of the solar and lunar cycles many as seven hundred rooms, as well as numer- (Sofaer, Sinclair, and Donahue 1991). Most of the ous kivas, including great kivas, the large ceremo- major buildings also appear to be organized in a nial chambers of prehistoric Pueblo culture (Lekson 225 Figure 9.1. The San Juan Basin and adjoining region, showing the buildings and roads of the Chacoan culture. The inset shows the relation of this region to the present-day states. (Suzanne Samuels, By Design Graphics; © 1995 226 by The Solstice Project) Anna Sofaer Figure 9.2. Aerial view of central area of Chaco Canyon, looking north. The photograph shows three major buildings: Pueblo Bonito (left), Pueblo Alto (above center), and Chetro Ketl (right). Casa Rinconada (bottom center) and New Alto are also shown. (Photograph by Adriel Heisey, © 1995 by Adriel Heisey) 1984; Marshall et al. 1979; Powers, Gillespie, and of the buildings suggests that extensive planning Lekson 1983). and engineering were involved in their construc- The construction of the major Chacoan build- tion (Lekson 1984; Lekson et al. 1988). ings employed enormous quantities of stone and No clear topographic or utilitarian explana- wood. For example, 215,000 timbers—trans- tions have been developed for the orientations of ported from distances of more than 80 km—were the Chacoan buildings. The buildings stand free used in the canyon in the major buildings alone of the cliffs, and their specific orientations are not (Lekson et al. 1988). The orderly, gridlike layout significantly constrained by local topography.2 227 The Primary Architecture of the Chacoan Culture Anna Sofaer 228 Figure 9.3. Chaco Canyon, showing the locations and ground plans of ten major buildings (and two minor buildings). Four outlying major buildings are also shown. The astronomical orientations of the buildings are indicated. (Fabian Schmid, Davis, Inc.; and Suzanne Samuels, By Design Graphics; © 1995 by The Solstice Project) Figure 9.4. Aerial photographs of two major buildings in Chaco Canyon, Pueblo Bonito (upper) and Pueblo del Arroyo (lower) with ground plans of these buildings. (Photographs by Koogle and Pouls for the National Park Service; graphics by Suzanne Samuels, By Design Graphics; © 1993 by The Solstice Project) Although the need to optimize solar heating may dominated or constrained the Chacoans’ choice of have influenced the general orientations of the specific locations for their buildings.3 buildings, it probably did not restrict their orienta- The Chacoans also constructed more than two tions to specific azimuths. Similarly, environmental hundred kilometers of roads. The roads were of factors, such as access to water, appear not to have great width (averaging 9 m wide), and they were 229 The Primary Architecture of the Chacoan Culture developed, with unusual linearity, over distances of Scholars have commented extensively on the up to fifty kilometers. Their construction required impractical and enigmatic aspects of Chacoan extensive surveying and engineering (Kincaid buildings, describing them as “overbuilt and 1983). Investigations show that certain of the overembellished” and proposing that they were roads were clearly overbuilt if they were intended built primarily for public image and ritual expres- to serve purely utilitarian purposes (Lekson 1991; sion (Lekson et al. 1988; Stein and Lekson 1992). Roney 1992; Sofaer, Marshall, and Sinclair 1989; Some observers have thought that the Chacoan Stein 1989),4 and that they may have been con- buildings were developed as expressions of the structed as cosmographic expressions (Marshall Chacoans’ “concepts of the cosmos” (Stein and 1997; Sofaer, Marshall, and Sinclair 1989). Lekson 1992) and that their placement and design Scholars have puzzled for decades over why the may have been determined in part by “Chacoan Chacoan culture flourished in the center of the cosmography” (Marshall and Doyel 1981). One desolate environment of the San Juan Basin. Ear- report proposes that “Chaco and its hinterland are lier models proposed that Chaco Canyon was a related by a canon of shared design concepts” and political and economic center where the Chacoans that the Chacoan architecture is a “common administered a widespread trade and redistribu- ideational bond” across a “broad geographic tion system (Judge 1989; Sebastian 1992). Recent space” (Stein and Lekson 1992). That report sug- archaeological investigations show that major gests that the architectural characteristics of buildings in Chaco Canyon were not built or used Pueblo Bonito, one of the two largest and most primarily for household occupation (Lekson et al. central buildings of the Chacoan system, are rigor- 1988). This evidence, along with the dearth of ously repeated throughout the Chaco region. burials found in the canyon, suggests that, even at Thus, important clues to the symbology and ideol- the peak of the Chacoan development, there was a ogy of the Chacoan culture may be embedded in low resident population. (Estimates of this popula- its central and primary architecture and expressed tion range from 1,500 to 2,700 [Lekson 1991; in the relationship of this architecture to primary Windes 1987].) Evidence of periodic, large-scale buildings in the outlying region. breakage of vessels at key central buildings indi- Numerous parallels to the Chacoan expressions cates, however, that Chaco Canyon may have of cosmology appear in the astronomically and served as a center for seasonal ceremonial visita- geometrically ordered constructions of Mesoamer- tions by great numbers of residents of the outlying ica—a region with which the Chacoans are known communities (Judge 1984; Toll 1991). to have had cultural associations (Aveni 1980; Many aspects of the Chacoan culture—such as Broda 1993). Moreover, traditions of the descen- the transport of thousands of beams and pots— dants of the prehistoric Pueblo people, who live have struck archaeologists as having a “decided today in New Mexico and Arizona, also suggest aura of inefficiency” (Toll 1991). Other findings— parallels to the Chacoan cosmology and give us such as “intentionally destroyed items in the trash insight into the general cosmological concepts of mounds,” “plastered-over exquisite masonry,” and the Chacoan culture. strings of beads “sealed into niches” in a central great kiva—indicate esoteric uses of Chacoan con- Previous Work structions. It has been suggested that, in the “absence of any evidence that there is either a nat- Solstice Project studies, begun in 1978, docu- ural or societal resource to which Chaco could mented astronomical markings at three petroglyph control access by virtue of its location” (Toll sites on Fajada Butte, a natural promontory at the 1991), Chaco Canyon was the center of exchange south entrance of Chaco Canyon (Figure 9.3). of information and knowledge (Sebastian 1991). Near the top of the butte, three rock slabs colli- Two other archaeologists suggest that Chaco mate light so that markings of shadow and light on Canyon