Chaco Canyon, for all its wild beauty, seems an unlikely place for the Anasazi culture to take root and flourish. This is desert country, with long winters, short growing seasons, and marginal rainfall. Yet a thousand years ago, this valley was a center of Anasazi life. This people farmed the lowlands and built great masonry towns that connected with other towns over a far-reaching network of roads. In architecture, in complexity of community life, in social organization, the Anasazi of Chaco Canyon reached heights rarely matched and never surpassed by their kindred in the Four Corners region.
The cultural flowering of the Chaco Anasazi began in the early AD 900s. We can see it most clearly in the architecture. They started building on a much larger scale. Using the same masonry technique as before -- walls one stone thick with generaous use of mud mortar-they built multistory stone villages with rooms several times larger than in the previous stage of their culture. Six of the large pueblos -- Pueblo Bonito, Chetro Ketl, Una Vida, Peņasco Blanco, Hungo Pavi, and Kin Bineola -- were started at this time. This pattern of a large pueblo with oversized rooms, surrounded by conventional villages, caught on throughout the region. New communities built along these lines sprang up. Old villages built similarly large pueblos. Eventually there were more than 75 of these "towns,'' most of them closely tied to Chaco by an extensive system of roads.
By AD 1000 Chaco was firmly established as the political and economic center of the Chaco Plateau. There may have been as many as 5,000 persons living in some 400 settlements in and around Chaco or as few as 2,000, depending upon which assumptions are used to estimate the population. A new masonry technique -- the use of masonry walls with rubble cores and outer surfaces of shaped stones -- allowed walls to rise to more than four stories in height. Some large buildings show signs of being planned from the start, in contrast to the usual Anasazi custom of adding rooms as needed. Chaco at this time may have been the hub of an extensive political and economic system that drew in goods and commodities and directed affairs over a wide region.
How to account for this blossoming? One theory is that Chaco developed as an administrative and ritual center mainly in response to environmental fluctuations. The vagaries of weather made farming unreliable. One year might be wet, another dry, one growing season long, another short. According to this theory, Chaco may have been a kind of capital that directed the agricultural life of the region, tempering good years with bad. Food could be stored here and redistributed as needed. The outlying towns can be thought of as satellites that performed for their locality the same function that Chaco did for the region.
The decline of Chaco apparently coincided with a prolonged drought in the San Juan Basin between 1130 and 1180. Lack of rainfall combined with an overtaxed environment may have led to food shortages. Even the clever irrigation methods of the Chacoans could not overcome prolonged drought. Under these pressures Chaco and the outliers may have experienced a slow social disintegration. The people began to drift away. They retreated to beter watered regions, leaving behind impressive evidence of their former influence over a vast territory.
The Road System
The true extent of the ancient Chacoan road system, as revealed by aerial photographs, impressed even veteran archeologists. There were more than 400 miles of roads connecting Chaco to some 75 communities. The longest road presently known runs 42 miles north toward the prehistoric towns now called Salmon Ruins and Aztec Ruins. On the north-south roads, settlements lay at travel intervals of approximately one day.
These roads were not simply trails worn by centuries of foot travel. They were the productions of relatively sophisticated engineering and required a great deal of energy and thought to plan, construct, and maintain. They were laid out in long, straight lines with scant regard for terrain. The roads averaged 30 feet in width. Construction was simple. On sloping ground the roadbed was leveled and a rock berm built to retain the fill. Where the roads passed over bare rock, they were often bordered by masonry walls or a ling of boulders.
The roads appear to date from the 11th and 12th centuries, a time of expanding population. Several roads converged at Pueblo Alto from the north. From there well-defined stairways led to the canyon bottom.
Aside from its obvious purpose of easing travel within the Chacoan world, this network could have facilitated communications and the transport of goods and materials between towns and helped bind Chacoans into a single society.
Trade
During Classic times, Chaco was the center of a far-flung trading network. Goods were exchanged internally within the Chacoan system and externally with groups as far south as Mexico. Chaco's distinctive Cibola black-on-white pottery may have originated in out-lying towns to the south and west. One estimate is that only about 20 percent of the pottery used here was made here. This may have been because there was better clay in other villages and more wood available for firing the vessels.
What Chaco lacked in pottery it more than made up for in turquoise ornaments. Raw turquoise was imported from distant mines and transformed with exquisite craftsmanship into necklaces, bracelets, and pendants. Great quantities of such jewelry have been found here, more than at any other southwestern site. A small frog carved in jet, found in Pueblo Bonito, has eyes and a collar of turquoise.
Other evidence of the trading system are the many seashells (often strung into necklaces), copperbells, and remains of macaws or parrots found here. The two latter items suggest contact with Mexico, perhaps with the ancient Toltecs.
Masonry
The Chaco Anasazi were skilled masons. Working without metal tools or any formal mathematics, they put up vast communal buildings that still compel admiration. Their methods evolved over centuries. The earliest dwellings were constructed with simple walls one stone thick, with generous courses of mud mortar. The oldest walls in Pueblo Bonito used this type of masonry.
When the Chacoans began to build higher and more extensively, they employed walls with thick inner cores of rubble and fairly thin veneers of facing stone. These walls tapered as they rose, evidence of the planning that went into the large-scale constrcution of Classic times (AD 1020-1120). An early example of this type of wall is characterized by large blocks of irregular sandstone chinked with smaller stones set into the mortar.
About half the ground floor of Pueblo Bonito was build in the style of masonry types (late 11th century). Oddly enough, both styles were employed at roughly the same time. Though the patterns are pleasing, there's evidence that plaster covered the stonework. The last distinctive masonry style, called McElmo, appears in Kin Kletso, a late 11th century dwelling. Its walls were built with a thin inner core of rubble and thick outer veneers of shaped sandstone, somewhat similar to the masonry styles used at Mesa Verde. To some eyes, it's less workmanlike than the earlier types, but the Chacoans may have thought differently.
Return to the Chaco Canyon World Heritage description
Return to the NPS-US/ICOMOS Home Page
Return to the World Heritage Site map
Go to the NPS Home Page
Last modified 7/96