CARLISLE, PENNSYLVANIA—According to a New York Times report, geochemical analysis of Aztec and Mixtec turquoise artifacts conducted by geochemist Alyson Thibodeau of Dickinson College suggests the turquoise used in them had been mined in Mesoamerica, and not imported from the American Southwest, where ancient turquoise mines have been found. It had been previously thought that turquoise traveled south to Mesoamerica along a long-distance trade network before the arrival of the Spanish in the sixteenth century. “Not only do they have isotopic signatures that are absolutely consistent with the geology of Mesoamerica,” Thibodeau said, “but they are completely different from the isotopic signatures of the Southwestern turquoise deposits and artifacts that we have seen so far.” Thibodeau's colleague David Killick of the University of Arizona argues that the test results suggest there may have been no organized contact between Mesoamericans and people living in the American Southwest. For more on archaeology in Mesoamerica, go to “Circle of Life.”