ESR Dating at Archaeological Sites in Europe and Africa

欧洲和非洲考古遗址的 ESR 测年

• 批准号: 9709912
• 负责人: Bonnie Blackwell
• 金额: $ 10.1万
• 依托单位: CUNY Queens College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 1998-08-03
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9709912&HistoricalAwards=false
• 关键词: ESR; Dating; Archaeological; Sites; Europe

Drs. Bonnie Blackwell and Anne Skinner will conduct a series of laboratory experiments to improve the electron spin resonance (ESR) technique and then apply it in a variety of field contexts. ESR provides a method to date teeth and appropriate categories of stone artifacts which date between ca. 20,000 and possibly as much as 4,000,000 years old. Because both categories of artifacts are common in archaeological sites and because many such occurrences are not datable by other available techniques, ESR, if properly developed, can provide an important anthropological tool. The technique depends on the fact that buried objects absorb small amounts of uranium from the soil and the internal as well as external bombardment by disintegration byproducts creates time dependent displacement of electrons within the sample. ESR provides a method to measure the extent to which this has occurred. When the dose rate has been determined, it is then possible to calculate age. Many prehistoric peoples heated lithics before they fashioned them into tools because the structural changes caused by heating made the material easier to work. Luckily, heat also sets the electron displacement clock to zero thus making heat treated pieces amenable to ESR analysis. While it is feasible in principle and has produced intuitively reasonable dates, ESR is not well developed and the results are treated with understandable caution. Uranium uptake rates are hard to determine and several different models have been proposed. Blackwell and Skinner's research focuses on technique development. They shall compare tooth enamel with dentine and cementum and adjacent sediment to gain insight into uranium absorption. They shall also perform calibration tests through analysis of teeth and lithics from sites which have been securely dated by other techniques. Finally they shall examine and date materials from a series of important sites in both Europe and Southern Africa. The research therefore will both help to develop an important dating technique and yield data which will improve our understanding of the emergence of humans.

Bonnie Blackwell博士和Anne Skinner博士将进行一系列实验室实验，以改进电子自旋共振(ESR)技术，然后将其应用于各种领域。ESR提供了一种方法来确定牙齿和适当类别的石器的年代，这些石器可以追溯到大约20,000年到可能长达4,000,000年前。由于这两类文物在考古遗址中都很常见，而且许多这样的遗迹无法用其他可用的技术确定年代，如果得到适当的开发，ESR可以提供一个重要的人类学工具。这项技术依赖于这样一个事实，即埋藏的物体从土壤中吸收少量铀，解体副产品对内部和外部的轰击在样品中产生随时间变化的电子位移。ESR提供了一种方法来衡量这种情况发生的程度。当确定了剂量率后，就可以计算年龄了。许多史前人类在将石块制成工具之前先将其加热，因为加热引起的结构变化使材料更容易加工。幸运的是，加热还可以将电子位移时钟设置为零，从而使热处理后的样品易于进行ESR分析。虽然它在原则上是可行的，并产生了直观合理的数据，但ESR还没有很好地开发，对结果的处理也是可以理解的谨慎。铀摄取率很难确定，已经提出了几种不同的模型。布莱克韦尔和斯金纳的研究重点是技术开发。他们将牙釉质与牙本质、牙骨质和邻近的沉积物进行比较，以了解铀的吸收情况。他们还应通过对已通过其他技术确定年代的地点的牙齿和石块进行分析，进行校准测试。最后，他们将审查来自欧洲和南部非洲一系列重要地点的材料并确定日期。因此，这项研究将有助于开发一种重要的测年技术，并产生有助于提高我们对人类起源的理解的数据。