Soil and Water Chemical Analyses

Used to Determine Origin of Prehistoric Maize

Over the past few decades, some archeologists have come to the conclusion that Chaco Canyon in northern New Mexico could not have supported the number of people that lived at or visited it a thousand years ago. Recent USGS studies provide evidence that supports this conclusion and demonstrates that at least some maize was transported over considerable distances in pre-Columbian times

[Soil and water sample sites in Chaco Canyon.]

In studies done in cooperation with the University of Colorado, the Navajo Nation, and others, USGS scientists showed that little maize could have been grown in the San Juan Basin near Chaco Canyon and that much of the archaeological corn found there was imported from distant areas. Based on their analysis of trace element and strontium isotope distributions in soil and water samples collected from agricultural sites in the San Juan Basin, the researchers suggest that from time to time, the Chacoan population received foodstuffs from either the San Juan River system (Aztec and Salmon greathouses), from the Chuska slope, or from sites along the Rio Chaco downstream of Chaco Canyon. The scientists found that one or more of three widespread droughts that occurred in the early-11^th, middle-12^th and late-13^th centuries also affected the Mississippian Cahokians, the Anasazi, the Fremont, and the Lovelock cultures.

References:
Benson, L., Stein, J., Taylor, H., Friedman, R., and Windes, T.C., 2006, The agricultural productivity of Chaco Canyon and the source(s) of pre-hispanic maize found in the Pueblo Bonito Great House, in Staller, J.E., and others, eds., Histories of Maize - Multidisciplinary Approaches to the Prehistory, Linguistics, Biogeography, Domestication, and Evolution of Maize: San Diego, Elsevier/Academic Press, p. 289-314.

Benson, L.V., 2004, Sources of ancient maize found in Chacoan great houses: U.S. Geological Survey Fact Sheet 2004-3035.

For additional information, or contact Larry V. Benson, lbenson@usgs.gov