With National Science Foundation support Dr. Mostafa Fayek and his colleagues will begin a 2-year research project to conduct a turquoise sourcing study along the northern frontier of Mesoamerica, which constitutes the border between Mexico and the United States including southwestern portions of the United States. The team brings together both geologists and archaeologists to conduct a coordinated investigation, which will reconstruct prehistoric southwestern turquoise trade networks and strengthen the theory, that Chacoan or other Anasazi cultures from central and southern Mexico were economically and culturally linked to Mesoamerica. The team has a suite of turquoise samples, which they have obtained from seven modern and archaeological mining areas throughout the southwestern United States and Mexico. They will apply a novel isotopic technique that will allow them to unambiguously distinguish between turquoises from each mining area. Although, previous trace element and isotopic studies have unsatisfactorily differentiated between the turquoise source areas in southwestern United States, a preliminary study by Dr. Fayek and his colleagues has shown that turquoise from each mining district has a unique O and H isotopic signature. Thus, the O and H isotopic composition of turquoise is potentially a powerful tool for characterizing and distinguishing between source regions. The team will analyze additional turquoise samples from a wide range of sources to further substantiate this method. This method will then be applied to archaeological artifacts, which will allow the turquoise in the artifacts to be traced to specific mining region. Dr. Fayek and his colleagues will use an instrument called the ion microprobe, which allows O and H isotopic analysis of small (200 mm) solid samples, thus only the smallest pieces of archaeological artifacts are required. Their research will focus on three questions: 1) is the H and O isotopic composition of turquoise within a sample or single mine sufficiently homogenous such that we can distinguish between turquoise deposits within a single source region? (2) Can we use the O and H isotopic composition of turquoise to distinguish between regional source areas? (3) Can we use the O and H isotopic composition of turquoise artifacts to link them to a particular mining region and hence reconstruct the prehistoric turquoise trade network?
This research is important for several reasons. If preliminary results are confirmed, a 'source fingerprint' could be available in a few years for turquoise, permitting archaeologists to identify the sources of turquoise found at sites across the continent and providing new insight into pre-contact trade patterns in North America. The research will enhance the infrastructure for research and education at the university level through partnership with Oak Ridge National Laboratory (ORNL). Students and faculty from both the departments of Geology and Anthropology at the University of Tennessee will be introduced to the world-class facilities and expertise at ORNL, which otherwise would be inaccessible.
