Public Release: 

Misunderstanding the prehistoric southwest: what happened at Chaco?

University of Colorado at Boulder

Two University of Colorado at Boulder researchers have developed intriguing theories on the mysterious demise of the Chaco Canyon Pueblo people and the larger Chaco region that governed an area in the Southwest about the size of Ohio before it collapsed about 1125.

Steve Lekson, curator of anthropology at the CU Museum, believes a powerful political system centered at Chaco Canyon in northern New Mexico may have kept other Pueblo peoples under its thumb from about 1000 to 1125. As the capital city of a huge region, Chaco became a place to store and exchange commodities, and the elite rulers probably exacted goods and taxes from outlying Chacoan villagers.

Chaco was the first stable settlement in the Southwest, sporting a dozen huge, multistoried sandstone buildings known as "great houses" that surrounded a plaza. It appears that a hundred or so elite people lived in each great house, with another 1,000 or so people living in single-family kivas outside the city center.

Lekson refers to Chaco as "the 800-pound gorilla of Anasazi archaeology" and possibly the major player in Pueblo prehistory. "It was an elite community living in a showy, ceremonial city that ruled a region containing tens of thousands of people."

Roughly 150 Chaco "outliers" up to hundreds of miles distant -- including Colorado's famed Mesa Verde -- show Chaco's influence, including the construction of multi-storied great houses. One, a site adjacent to the town of Bluff, Utah, that has been studied by Lekson, CU-Boulder anthropology Associate Professor Catherine Cameron and CU students, is one of the farthest northeast "outliers" to Chaco.

"Things started to happen in Chaco in the 9th century," said Lekson. "At that time, small settlements outside the canyon were fighting with each other. With the rise of Chaco, that raiding and feuding ended."

A paper on the subject by Lekson and Cameron was presented at the American Association for the Advancement of Science meeting in Denver Feb. 13 to Feb. 18.

Lekson believes the collapse of Chaco may have begun with a spiritual tug-of-war between the Chaco elite and their followers and a second group lured south by new religious and spiritual beliefs springing up without an oppressive government. Chaco Canyon was always arid, and a drought likely sent the elite and their followers north to Aztec, located on the Animas River.

"I think there may have been some serious policing with 'goon squads' in the Chacoan region about the time the Chaco Empire was collapsing, and some serious slicing and dicing began as local warfare broke out," said Lekson.

"Toward the end, there may have been policing in the Chacoan region in an attempt to maintain order. But when Chaco was collapsing, some serious violence and warfare broke out," he said. "Chaco could no longer control its region."

The Chaco elite ordered the building of a wide path known today as the Great North Road due north about 60 miles to the Aztec Pueblo, a minor blip on the region's radar screen in the Southwest at the time but one that turned into a second major capital beginning about 1110 and lasting until 1275, he said.

A great drought about that time likely caused the center at Aztec to pull up stakes, reverse cosmological direction and make a beeline directly south. While thousands of Aztec people joined western and eastern pueblos, thousands more led by the ruling elite marched nearly 450 miles straight south to build an even bigger city at Paquime in present day Chihuahua, Mexico, that lasted until about 1450.

Lekson calculated Aztec, Chaco and Paquime are off a north-south meridian by only about three miles, explainable by the terrain and technology, which likely included "line-of-sight" travel and stellar navigation, he said. Similar architectural features at all three cities that are found nowhere else bolster Lekson's novel theory, which he calls the "Chaco Meridian."

Continuing research by Professor Cameron and CU students at the Bluff great house in Utah indicates the great house was occupied after the crash of the Chacoan empire and the berms surrounding it were built during the Aztec heydays. "It was an eye-opener because it indicates the berms were built long after Chaco collapsed," Cameron said.

The Bluff people may have "experienced a religious revival," perhaps tied to the growing influence of the Aztec culture centered near present-day Aztec, N.M." she said.


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