ALBUQUERQUE – Salty soils and dry conditions throughout northwestern New Mexico’s Chaco Canyon would have made it difficult to grow enough corn to sustain the multitudes of people who resided at the once monumental gathering spot centuries ago, according to a new study.
University of Colorado-Boulder scientist Larry Benson’s research adds fuel to the theory that Chaco inhabitants relied on food imports from elsewhere in the Four Corners region.
A UNESCO World Heritage site, Chaco Culture National Historical Park encompasses what’s left of an ancient civilization whose architecture and cultural influences have been a source of mystery for years.
Some archaeologists have theorized that Chaco’s influence spread far and wide from its remote desert location to cover an area twice the size of Ohio. The park includes a series of great houses, or massive multistory stone buildings, some of which were oriented to solar and lunar directions and offered lines of sight between buildings to allow for communication.
The archaeological record also includes evidence of a network of ceremonial roads that lead to Chaco as well as pottery and tool-making materials that indicate the inhabitants regularly traded with others.
The latest study offers just one more piece to the puzzle while raising questions about Chaco’s population and the suggestion by some that corn must have been plentiful to feed the masses.
“There’s very little actual data to prove that,” Benson said. “I’m a geochemist, not an archaeologist, so I’m used to collecting data and analyzing it to see what it says.”
Much of the corn consumed by those at Chaco may have come from more fertile lands near the Chuska Mountains along the Arizona-New Mexico border, said Benson, an adjunct curator of anthropology at the university’s natural history museum.
He considered soil samples, previous research that looked at the isotopic signature of plants in the region and tree ring data compiled by researchers at the University of Arizona. The tree rings indicate the minimum amount of annual precipitation necessary to grow corn was exceeded less than 3 percent of the time.
Nathan Hatfield, chief interpreter at Chaco park, said Friday that archaeologists and others who have studied Chaco have long assumed that food was coming into the community from elsewhere and the study helps confirm that belief.
Despite the lack of water and other natural resources in the immediate area, Hatfield said residents of Chaco weren’t totally reliant on imports.
“Archaeological evidence does show signs of cultivated fields and also different forms of irrigation and water control so they were certainly making efforts,” he said. “How successful those efforts were, I’m sure in some years it was very difficult.”
On the eastern slopes of the Chuska Mountains, the study suggests winter precipitation was substantial and features of the landscape helped to funnel spring runoff to irrigated fields.
Benson said more attention should be paid to outlying areas such as the Chuskas and their connection to Chaco. Aside from food, experts say timber from the mountains was used in the construction of Chaco’s buildings.
With its long winters, marginal rainfall and short growing seasons, many archaeologists are puzzled as to why inhabitants chose the canyon. It was never a Garden of Eden, Benson said.
Hatfield said there are many theories.
“You didn’t have readily available resources, yet they still decided to build there and that’s why we think there were more spiritual motives behind it,” he said. “They looked at the layout of the canyon and the different features and determined this is it, this is where we have to do our thing.”