Ch.4: Chacoan Architecture

URBAN GENESIS AT CHACO: Case Study of the Origin of Civilizations. Chapters: 1 2 3 4 5 6

4.3 Settlement and Development in the Canyon

The figure above shows the location of known dwellings within Chaco Canyon. At the end of the ninth century, all of these dwellings were unit pueblos, occurring individually or in small clusters. They consisted of two-story roomblocks that were usually two rooms deep, built with crude masonry techniques. The pit-structures were increasingly formalized, and partially lined with either upright slabs or with coursed masonry (Cordell 1984:101).
The development of the great-houses in Chaco Canyon is shown below. Most Chacoan public architecture was built in a series of five construction booms: 900-940, 980-1040, 1050-1060, 1060-1100, and 1100-1140 (Lekson 1984:259). For brevity I have combined the third and fourth growth phases into figure 4.8. Each 'boom' or phase is characterized by changes in method of both construction and design. As a result, great-houses were built in a variety of forms reflecting the periods in which each was first laid out and subsequently modified (see figure 4.9 also). In spite of these changes Chacoans took great pains to respect and preserve older structures, an effort that is most clearly expressed in the striking difference between the designs of new buildings and the contemporaneous remodelings of older structures.

4.6 First Phase Greathouses

Figure 4.6 shows the first phase of great-house construction. Pueblo Bonito and Una Vida began as unit pueblos in the tenth and ninth centuries; they were transformed into great-houses by the addition of large room-blocks facing onto level plazas. The ruin of Peñasco Blanco has never been systematically excavated, so its initial form is unknown. However, Pe?asco Blanco appears to be the earliest great-house: a tree-ring date from one of the roof-beams in its oldest section dates to ad 898. The expansion of Pueblo Bonito into a great-house began around ad 920, and Una Vida around 930. The latter two great-houses will be discussed in greater detail in part 2 of this chapter.

4.7 Early Classic Phase

Figure 4.7 shows the result of construction activity that began around ad 980 at Hungo Pavi and culminated with a series of construction projects around 1020 to 1040. During this period other great-houses began to be built outside of the canyon as well, as the Chaco culture became a regional system. Within the canyon, the second phase was characterized by the expansion of existing great-houses and the initiation of a series of new great-houses. Masonry techniques were considerably improved, resulting in walls that were stable and strong enough to support multiple-story construction. 'Classic' is a term used by archaeologists to describe this period in which most of the Chaco complex was built. The resources and organization of labor required to carry out numerous construction projects in this period indicate that political power had been consolidated by the end of the tenth century. In figure 4.6, note the striking difference in the form of the new great-houses. Note that the three new great-houses begun in this period are straight double rows of rooms, very different from the arcuate Early great-houses.

4.8 Late Classic Phase

Figure 4.8 shows the results of at least forty years of continuous building activity. Only one new great-house was started at this time (Pueblo del Arroyo), but all of the existing great-houses were expanded in a similar fashion. Additional rows of rooms were added to the original room-blocks, and wings were added to the east and west ends of each building. Not only did this increase the definition of the plazas, but the plazas themselves were again leveled and resurfaced. Great kivas were built in each great-house, including a second great kiva at both Una Vida and Pueblo Bonito. The original great kivas at each of these great-houses were filled in and abandoned.

Furthermore, two additional great kivas were built at sites away from any great-houses: Casa Rinconada was built across from Pueblo Bonito and Chetro Ketl, due south of Pueblo Alto. Kin Nahasbas was built near the top of a natural pyramid of talus and soil at the east end of the canyon. I do not know whether earlier versions of Casa Rinconada predate the 'Late Classic' period, but the masonry of the existing structure dates from the latter half of the tenth century. Kin Nahasbas was only surveyed and then backfilled, so I know nothing about the dates of its use.

4.9 Late Phase

Figure 4.9 shows the fifth phase of construction in the canyon, which ended abruptly around 1145. In this period, great-house design changed significantly, both in the additions that were made to existing great-houses and in the four new great-houses that were begun in this period. Late-period great-houses were each built in one or two brief construction campaigns as singular, compact blocks containing a few small kivas in the core. They had no enclosed plazas nor any great kivas. During the late period the plazas of early and classic great-houses were also fully enclosed. Individually, each late construction campaigns was still very large, ranging from 40,000 person-hours to 85,000 person-hours; the Chacoans could still mobilize considerable amounts of labor at least as late as ad 1130 (Lekson 1984:259). Yet after 1145, construction activity within the canyon virtually stopped. Only a few small, haphazard structures built in the late twelfth or early thirteenth century, the during a brief reoccupation of the canyon. By 1300 the canyon was abandoned, only to be reoccupied by Navajo at the end of the seventeenth century.