Preston's Chaco Book of Judge's: One

According to Judge, Chaco Canyon probably started out as small series of settlements in the highly marginal area along Chaco Wash. From A.D. 900 to 1050, rainfall in the canyon was highly variable. Had the people of Chaco canyon been typical Anasazi, their settlements along the wash never would have amounted to much. In the early period, the Anasazi were scattered across the Southwest, living in independent communities, possibly speaking several different languages, but all practicing a similar culture and religion. They built small settlements and moved often, usually when the local game, timber, and other resources had been played out. If they followed the typical pattern, the people of Chaco would eventually have moved on, leaving a few scattered houses. It would have been a minor site.

But the people of Chaco were not typical. They had, Judge theorized, a unique skill: the ability to process and finish a deeply sacred and valuable material: turquoise. The people of Chaco, apparently, traded in raw turquoise and traded out beautifully finished beadwork, inlay, mosaic work, pendants, and carvings. (snip)

During the days of Chaco, the turquoise had to be mined by hand using stone tools and then transported several hundred miles southwest to Chaco. There it was carved, drilled, polished, and inlaid without metal tools, using only stone, bone, wood, and grasses high in silicates for polishing. The Chaco workshops turned out exquisite work, including beads that were almost microscopic in size with holes drilled that would barely fit a human hair. It took immense skill to work the soft, easily breakable turquoise without metal tools or the wheel.

Around 1020, Chaco seems to have developed a monopoly in the processing and distribution of this sacred material-what Judge called "the primary symbol of the ritual." Turquoise was probably an essential aspect of the rain ceremonies. As a result, Chaco started to become an important religious center. An elite priesthood class-something previously unknown among the Anasazi-appears to have developed. At the same time, Chaco seems to have gained cultural and perhaps political ascendancy over communities beyond the canyon boundaries.

Then, from 1050 to about 1085, there came an extraordinary and fortuitous change in the climate. At Chaco Canyon and all across the San Juan Basin the rains began to fall. And they fell, and they fell. Not once did the rainfall dip below the seasonal averages. In an area where a mere inch or two of rain could mean the difference between a bumper crop and a burnt-out field, this steady rainfall made a tremendous difference.

The increased rainfall, Judge theorized, had an enormously strengthening effect on Chaco's power and influence. By controlling the supply and distribution of turquoise, Chaco had gained control over the rain ceremonies and religious system of the Anasazi. And then year after year, like never before, the rains came. What more proof could the Anasazi have needed to affirm this great religious experiment centered at Chaco?

Vast building projects began in Chaco Canyon. Across the San Juan Basin, too, dozens of magnificent Chacoan structures started to be built, linked to Chaco by ceremonial roads dotted with religious complexes, shrines, and lighthouses.

from Talking to the Ground by Douglas Preston