Chaco Canyon, New Mexico (page 2 of 3)

The Chaco Phenomenon

Ruins at Chaco Canyon  Photograph by Dr. Sylvester Allred.

Between 900 and 1150 A.D., the Anasazi of the Chaco Canyon region built fourteen monumental pueblo "Great Houses" — huge, formal, multi-storied structures with 100 to 650 rooms in each. Many great kivas, small pueblo houses and other structures were also built.

The construction of all of these magnificent buildings required the Anasazi to cut hundreds of tons of sandstone from the canyon cliffs and to fell an estimated 250,000 trees. The forests in the vicinity of the canyon were soon gone, and even today there exist only isolated stands of conifers in the region.

The depletion of the local forest resources required the transport of thousands of trees from as far as 75 km away in locales such as the Chuska and San Juan Mountains, without the aid of beasts of burden. This wood was used not just for necessary structural support, but also for constructional extravagances such as cribbed-log roofs, which may have been a show of wealth and power for the Chaco Anasazi.

The entire design of the Chaco Canyon village seems to have been planned; the Great Houses were constructed with careful symmetry and many were aligned with the cardinal directions and the solstices. Morphologically similar Great Houses, kivas, and other structures were also built in the many Chaco "outlier" settlements across the Colorado Plateau, although none approached the dimensions of the largest Great Houses at Chaco.

During the Chaco fluorescence, population levels swelled within the canyon. Depending on the formula used to calculate populations, the numbers vary from just over 2,000 to well over 5,000 people. An important factor contributing to the success of this period was a favorable climate shift to warmer, wetter conditions. Water diversion systems employed by the Chaco Anasazi were sophisticated and labor-intensive. As there were no permanent streams in Chaco Canyon and the periodic torrents down the central wash were too unpredictable and difficult to control, the prehistoric farmers devised a system of techniques to channel runoff from mesa tops. Designed to maximize water diversion, these techniques involved a combination of ditches, headgates, terraced cliffs, overflow ponds, and masonry irrigation canals and dams. This system allowed a remarkably equal distribution of floodwater to the carefully constructed, leveled and bordered fields on the canyon bottom.

Throughout all of the Anasazi phases, small game such as deer, rabbits and prairie dogs were consumed, and a variety of wild plants were gathered. Yet a good deal of evidence points to the overexploitation of the natural resources in the region, including arable soil, local fauna, trees for construction and fuel, and wild edible or medicinal plants. The Chacoan Phenomena may have largely existed to provide a redistribution system among the Anasazi peoples of the region, with Chaco Canyon as the main storage and administrative focus. Since conditions for agriculture were marginal, and local resources were in constant flux depending on climatic shifts and human usage, the Anasazi of the Chaco region may have adapted by amassing food in one place and redistributing it to those in need, based on social and ritualistic rules.

This theory is well supported by another astounding aspect of the Chaco Phenomena: the extensive and well-engineered road system that emanates from Chaco Canyon. Though not easily detected from the ground, aerial photography and other remote sensing techniques such as thermal infrared multispectral sensing have detected over 200 miles of prehistoric roads, and estimates for as-yet undetected roads range as high as 1,500 miles. The roads, which date to the 11th and 12th centuries, were built to an average width of 30 feet and carefully surveyed by unknown means so as cross the terrain in a virtually straight line. Little attention was paid to topography by the prehistoric road engineers; stairways, ramps, scaffolds and toeholds were cut into the stone when necessary. Many of the roads, particularly those closest to the canyon, had earthen berms or adobe curbs, signaling stations and roadside shrines called herraduras. There is evidence that the roads were well maintained throughout Anasazi occupation.

Many of the roads connected Chaco to other settlements or to important resource bases, and were likely used for transport and communication. Examples include the road to the Chuska Mountain area which supplied timber and pottery, as well as the "Great Road North" which connected Chaco Canyon with new settlements on the San Juan River. Long distance trade with Mesoamericans for items such as macaws, copper and shells was also aided by the road system. Many of the roads extend for a distance and then suddenly stop or run parallel to each other for long distances away from any settlements. Thus the Chacoan roads probably served multiple purposes — while some were functional, others may have served as symbols of spiritual values and/or used in formalized rituals.

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Page 3 - After the Anasazi
References