Chemical Analysis Of Ancient African Glass Beads

在撒哈拉以南非洲的无数考古遗址中发现了玻璃珠。 然而，从在欧洲接触之前的遗址上发现的玻璃珠中获得信息已经被证明是困难的。 由于玻璃不是由撒哈拉以南非洲的原材料制造的（有一个可能的例外），考古学家知道玻璃珠是在全球经济的早期版本中连接旧世界大部分地区的贸易物品。 如果考古学家能够确定用于制造特定珠子的玻璃是在哪里制造的，那么他们就可以研究过去两千年将非洲与更广阔的世界联系起来的贸易模式。 经验表明，发现玻璃来源的唯一方法是通过化学分析。 30年前曾尝试过，但由于分析技术不精确，以及缺乏非洲以外的玻璃制造中心的比较数据，没有取得多大成功。 然而，现在已经发生了很大的变化：对古代欧洲和亚洲的玻璃进行了精确的化学分析，包括在玻璃工厂发现的材料，同时开发了一种新技术，激光烧蚀电感耦合等离子体质谱法，可以对玻璃珠中发现的许多化学元素进行定量分析，而不会损坏珠子本身。 在国家科学基金会的支持下，彼得·罗伯特肖博士在联邦资助的密苏里州大学研究反应堆中心科学家的协助下，将分析来自撒哈拉以南非洲地区的大约1000个玻璃珠，以回答两组对了解非洲过去至关重要的问题。 首先，他们将检查在非洲东部沿着和南部非洲内陆发现的珠子，以回答几个问题：这些玻璃来自哪里-北非、西南亚、印度、中国还是东南亚？ 在葡萄牙人到达东非之前的一千年里，印度洋贸易模式发生了什么变化？ 不同的非洲港口是否从不同的来源获得玻璃？ 非洲内陆的遗址，如大津巴布韦，是否从许多港口和许多来源获得珠子？ 内陆和沿海之间的贸易模式是否随着时间的推移而改变？ 其次，Robertshaw和同事们将寻求发现连接尼日利亚东南部Igbo-Ukwu与更广阔世界的贸易路线。 伊博-乌库以当地制造的9世纪青铜器皿而闻名。 在这里还发现了16万颗玻璃珠。 没有人知道这些财富是如何积累起来的，也没有人知道连接伊博-乌库与可能的玻璃制造中心的贸易路线在哪个方向。 一些学者认为这些珠子是从北非海岸（伊斯兰教的Ifriqiya）甚至西班牙穿越撒哈拉沙漠而来的，另一些学者则认为它们是通过苏丹的基督教王国或印度起源于开罗。 这项研究将调查这些相互竞争的假设，并探讨一些玻璃是否是由非洲本土的玻璃工业制造的，可能在北方尼日利亚。 研究结果将使历史学家能够更坚定地将非洲置于欧洲扩张之前存在的全球经济背景下。

Glass beads have been found at innumerable archaeological sites in sub-Saharan Africa. However, obtaining information from glass beads found on sites that date to before European contact has proven difficult. Since glass was not manufactured from raw materials in sub-Saharan Africa (with one possible exception), archaeologists know that glass beads were trade items that linked large parts of the Old World in an early version of the global economy. If archaeologists could establish where the glasses used to make particular beads were manufactured, then they could study patterns of trade that linked Africa to the wider world over the last two millennia. Experience has shown that the only way to discover the sources of the glass is through chemical analysis. This was tried thirty years ago but without much success because of imprecise analytical techniques and a lack of comparative data from glass-making centers outside Africa. However, much has now changed: accurate chemical analyses have been undertaken of ancient European and Asian glasses, including material found at glass factories, while a new technique, laser-ablation inductively-coupled-plasma mass-spectrometry, has been developed that permits quantitative analysis of numerous chemical elements found in glass beads without damage to the beads themselves. With National Science Foundation support, Dr. Peter Robertshaw, with the assistance of scientists at the federally funded University of Missouri Research Reactor Center, will analyze about 1000 glass beads from sites throughout sub-Saharan Africa to answer two sets of questions of central importance in understanding the African past. First, they will examine beads found at sites along the coast of eastern Africa and in the southern African interior to answer several questions: Where did the glass come from - north Africa, southwest Asia, India, China, or southeast Asia? What changes in patterns of Indian Ocean trade occurred in the millennium preceding the arrival of the Portuguese in East Africa? Did different African ports obtain their glass from different sources? Did sites in the interior of Africa, such as Great Zimbabwe, receive beads from many ports and many sources? Did patterns of trade between the interior and the coast change through time? Second, Robertshaw and colleagues will seek to discover the trade routes that connected Igbo-Ukwu in southeastern Nigeria to the wider world. Igbo-Ukwu is famous for its ninth-century bronze vessels of local manufacture. Here too were discovered 160,000 glass beads. Nobody knows how this wealth was amassed and in which direction lay the trade route that connected Igbo-Ukwu with the likely glass manufacturing centers. Some scholars think that the beads came across the Sahara from the north African coast (Islamic Ifriqiya) or even Spain, others argue for an origin in Cairo via the Christian kingdoms of the Sudan, or perhaps India. This research will investigate these competing hypotheses and also explore whether some of the glass was manufactured by an indigenous African glass industry, possibly in northern Nigeria. The results of the research will permit historians to place Africa more firmly within the context of a global economy that existed prior to European expansion.