Developing Heavy Stable Isotopes for Provenance of Turquoise, Metals and Glass

开发用于绿松石、金属和玻璃来源的重稳定同位素

• 批准号: 0852270
• 负责人: David Killick
• 金额: $ 26.98万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0852270&HistoricalAwards=false
• 关键词: Developing; Heavy; Stable; Isotopes; Provenance

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).With the support of the National Science Foundation, an interdisiplinary team at the University of Arizona will greatly expand work in progress on characterizing (1) sources of turquoise in the southwestern USA and northern Mexico; (2) sources of native copper in north America; (3) sources of copper in North and West Africa; and (4) glass trade beads of the Muslim era in Africa. The team consists of an archaeologist (David Killick), two geochemists (Joaquin Ruiz and John Chesley) and three graduate students (Thomas Fenn, Lisa Molofsky and Alyson Thibodeau).Some of the inorganic materials that were highly valued by past societies are both geologically scarce and unevenly distributed across the earth's surface. For example, Mesopotamia and the West African Sahel both have few copper ore deposits, and thus the populations of these regions had to obtain almost all of the copper that they consumed through long-distance trade. Turquoise only forms around copper ore deposits in semi-arid areas, but is often recovered from archaeological sites in regions where there are no local sources, such as Mesopotamia and central Mexico. These materials (and others, like obsidian, tin and jade) are therefore potentially valuable indicators of the extent, duration and scale of prehistoric contacts between distant regions. Actual proof of long-distance exchange can only be obtained by matching the chemical or mineralogical composition of archaeological artefacts to the composition of specific geological sources of these materials (the field of provenance analysis). A necessary first step is to demonstrate that all potential sources of these materials can in fact be distinguished from each other on chemical or mineralogical evidence. The methods most commonly employed for provenance analysis (trace element ratios, optical petrography and x-ray diffraction) are not likely to be fully successful in distinguishing copper and turquoise deposits, which are highly variable aggregates of copper minerals and host rocks. This study will rely instead upon the measurement of isotopic ratios of lead and strontium. Ratios of these isotopes are less variable within particular deposits than are trace element ratios, are not altered by weathering or smelting, and can often be related to regional geological processes (e.g. the assembly of subcontinents from terranes). Copper isotope ratios will also be used as a third line of evidence in some cases.The broader impacts of these studies will depend upon the empirical findings. If turquoise sources can be successfully discriminated from each other, archaeologists will have a powerful new way of investigating prehistoric interaction between Mexico and the southwestern USA. Similarly, if the geological sources of copper alloys and glass beads in archaeological sites in West Africa can be reliably inferred from isotopic and chemical composition, archaeologists will be able to study in some detail the early history of contacts between the Muslim world and sub-Saharan Africa - a topic of very wide popular interest, given that one-third of the population of Africa today are Muslims.

该奖项是根据2009年的《美国复苏与再投资法》（公法111-5）资助的。在国家科学基金会的支持下，亚利桑那大学的一个跨学科团队将大大扩展在美国西南部和墨西哥墨西哥西南部的绿松石来源（1）绿松石来源的工作； （2）北美本地铜的来源； （3）北非和西非的铜来源； （4）非洲穆斯林时代的玻璃贸易珠。该团队由考古学家（David Killick），两名地球化学家（Joaquin Ruiz和John Chesley）和三名研究生（Thomas Fenn，Lisa Molofsky和Alyson Thibodeau）组成。过去社会非常重视的无机材料都是地理上的地理上的，并且是地球上的地球上都有范围的。例如，美索不达米亚和西非萨赫勒人都没有铜矿矿床，因此这些地区的种群必须获得他们几乎通过长距离贸易消费的铜。绿松石仅在半干旱地区的铜矿矿床周围形成，但通常是从没有当地来源的地区的考古遗址中回收的，例如美索不达米亚和墨西哥中部。因此，这些材料（以及其他材料，例如黑曜石，锡和玉）是远处区域之间史前接触的程度，持续时间和规模的潜在有价值的指标。仅通过将考古伪像的化学或矿物学组成与这些材料的特定地质来源的组成（出处分析领域）相匹配，才能获得长距离交换的实际证明。必要的第一步是证明这些材料的所有潜在来源实际上可以在化学或矿物学证据上彼此区分。 最常用的作品分析方法（痕量元素比，光学岩石摄影和X射线衍射）不太可能完全成功地区分铜和绿松石沉积物，它们是铜矿物质和宿主岩石的高度可变聚集体。 这项研究将依赖于铅和锶同位素比的测量。这些同位素的比率在特定沉积物中的变化较小，而不是痕量元素比率，而不会因风化或冶炼而改变，并且通常与区域地质过程有关（例如，来自Terranes的亚容量的组装）。 在某些情况下，铜同位素比也将用作第三道证据。这些研究的更广泛影响将取决于经验发现。如果可以成功地互相区分绿松石，考古学家将有一种有力的新方法来调查墨西哥与美国西南部之间的史前互动。同样，如果西非考古遗址中的铜合金和玻璃珠的地质来源可以可靠地从同位素和化学组成中可靠地推断，考古学家将能够详细研究穆斯林世界与撒哈拉以南非洲之间的接触的早期历史，这是一个非常普遍的兴趣的话题 - 鉴于非洲人群的一个人群，这是一个非常普遍的普遍兴趣的话题。