Sourcing Turquoise Using O and H Isotopes

在国家科学基金会的支持下，Mostafa Fayek博士和他的同事们将开始一个为期两年的研究项目，在中美洲北部边境进行绿松石来源研究，该地区构成了墨西哥和美国之间的边界，包括美国西南部。该团队将地质学家和考古学家聚集在一起进行协调调查，这将重建史前西南部的绿松石贸易网络，并加强以下理论：来自墨西哥中部和南部的查科安或其他阿纳萨齐文化在经济和文化上与中美洲有联系。该团队有一套绿松石样本，他们从美国西南部和墨西哥的七个现代和考古矿区获得。他们将应用一种新的同位素技术，使他们能够毫不含糊地区分每个矿区的绿松石。尽管之前的微量元素和同位素研究未能令人满意地区分出美国西南部的绿松石产地，但法耶克博士和他的同事们的初步研究表明，每个矿区的绿松石都有独特的氧和氢同位素特征。因此，绿松石的氧和氢同位素组成可能是表征和区分源区的有力工具。该团队将分析来自广泛来源的更多绿松石样本，以进一步证实这种方法。然后，这种方法将应用于考古文物，这将使文物中的绿松石被追踪到特定的矿区。法耶克博士和他的同事们将使用一种名为离子微探头的仪器，它可以对小(200毫米)固体样本进行氧和氢同位素分析，因此只需要最小的考古文物碎片。他们的研究将集中在三个问题上：1)一个样品或单个矿山中绿松石的H和O同位素组成是否足够均匀，以至于我们可以区分单一来源区域内的绿松石矿床？(2)我们能否利用绿松石的O和H同位素组成来区分不同的来源区域？(3)我们能否利用绿松石制品的O和H同位素组成将它们与特定的矿区联系起来，从而重建史前绿松石贸易网络？这项研究之所以重要，有几个原因。如果初步结果得到证实，几年后可能会有绿松石的“来源指纹”，这将使考古学家能够确定在整个大陆发现的绿松石的来源，并为北美接触前的贸易模式提供新的见解。这项研究将通过与橡树岭国家实验室(ORNL)的合作，加强大学层面的研究和教育基础设施。田纳西大学地质学和人类学系的学生和教职员工将被介绍给ORNL的世界级设施和专业知识，否则这些设施将是无法进入的。

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.