Application of Luminescence Dating in North American Archaeology

也许考古学最重要的任务是为被发现的物质遗骸提供一个年表。 任何关于文化如何以及为什么在过去发生变化的陈述都是以准确和精确的年表为基础的。 考古学家利用一系列物理方法来确定年龄，最常见的是放射性碳测年。在欧洲广泛使用的发光测年法在美国考古学中的应用较少。 美国国家科学基金会正在支持由詹姆斯·费瑟博士领导的华盛顿大学发光测年实验室的研究，以扩大这种测年方法在美国考古学中的应用。 该研究涉及到一些用其他测年方法无法解决的年代学问题，特别适合于发光测年，发光可用于测定埋藏沉积物、陶器和烧成岩屑的年代。 原始陶器的年代测定，以及一些石器时代的年代测定，正在这个项目中得到解决。 发光可以追溯到陶器最后一次被加热的时间，通常是在它被制造或使用的时候。 由于陶器的制造或使用是考古学家感兴趣的事件，因此发光法的主要优点是提供陶器的直接年代，而不像其他年代测定方法那样依赖于陶器与其他已确定年代的事件的联系，这对本研究所要解决的一些年代问题有一些特别的优势： 1)考古学家对区域定居动态感兴趣，但小遗址，特别是那些主要包含表面材料的遗址，很难确定日期，因此很难将其列入定居年表。 这些遗址的年龄与较大的遗址相同还是不同，这对人口如何分散在景观中意味着什么？未经鉴定的陶器碎片往往是在这些遗址发现的唯一文物。 发光是唯一可以确定它们年代的方法。 2)考古学中一个特别令人烦恼的问题是不同年代的材料混合在一个存款中。这混淆了对文化历史的解释，模糊了变化克里思的证据。 通过直接测定人工制品的年代（这里是陶器碎片），就像发光一样，人们可以开始区分不同的职业。 3)在一个地点被占领的时间长短是了解人口趋势及其对环境、经济和政治复杂性的影响的一个重要变量。 确定持续时间在考古学中一直是个问题。 通过直接测定一些陶器碎片的年代，发光可以提供一个统计上可量化的持续时间的测量。 陶器的使用寿命往往相对较短，强调具有最脆弱织物的碎片将最大限度地减少可能持续时间超过职业的文物问题。 4)确定前陶瓷遗址的年代也很困难。 发光能够确定热处理石器和陶器的年代，并为改进美国最早的年表提供了解决方案。这些问题正在通过在密西西比河谷、田纳西河谷、密西西比东部、亚拉巴马中部以及中西部和东南部的其他地区的研究来解决。 此外，还在研究如何提高陶器发光测年的准确性和精确度。

Perhaps the most important task of archaeology is providing a chronology for the material remains that are recovered. Any statements about how and why cultures have changed in the past are predicated on an accurate and precise chronology. Archaeologists have utilized an array of physical methods for determining age, most commonly radiocarbon dating. Luminescence dating, which is widely used in Europe, has seen less use in American Archaeology. The National Science Foundation is supporting research by the University of Washington's Luminescence Dating Laboratory, directed by Dr. James Feathers, in expanding the application of this dating method in American archaeology. This research involves addressing some chronological problems that have not been resolved by other dating methods but which are particularly suitable for luminescence dating.Luminescence can be used to date buried sediments, pottery and burned lithics. Primarily pottery dating, with some lithic dating, is being addressed in this project. Luminescence dates pottery to the last time it was heated, usually when it was made or used. Since the manufacture or use is the event that archaeologists are interested in, luminescence has the principle advantage of providing direct dates for pottery and does not rely, as do other dating methods, on association of the pottery with some other event that is dated.This has some particular advantages for some chronological problems, which are being addressed by this research: 1) Archaeologists are interested in regional settlement dynamics, but small sites, particularly those which contain mainly surface material, are difficult to date and thus place in a settlement chronology. Are these sites the same age or different age than larger sites and what does this mean for how the population was dispersed across the landscape? Undiagnostic pottery sherds are often the only artifacts found at these sites. Luminescence is the only method that can date them. 2) A particularly vexing problem in archaeology is the mixing in one deposit of materials of different age. This confounds interpretations of cultural history and blurs evidence on the tempo of change. By directly dating artifacts (in this case pottery sherds), as luminescence can, one can begin to tease apart the different occupations. 3) Duration of occupation in one location is an important variable for understanding population trends and their impact on environment, economy and political complexity. Determining duration has long been problematic in archaeology. By directly dating a number of pottery sherds, luminescence can provide a measure of duration that is statistically quantifiable. Pottery tends to have a relatively short use-life, and emphasis on sherds that have the most fragile fabrics will minimize problems of artifacts that may last longer than the occupations. 4) Dating pre-ceramic sites can also be difficult. Luminescence is able to date heat-treated stone tools as well as pottery and offers a solution to improving the earliest chronologies in America. These problems are being addressed in this research through work in the Mississippi Valley, the Tennessee Valley, eastern Mississippi, central Alabama, and other localities in the Midwest and Southeast. Research into improving the accuracy and precision of luminescence dating of pottery is also being undertaken.