Dissertation: The Temporal Resolution of Oxygen and Carbon Stable Isotope Measurements in Tooth Enamel

这个博士论文研究项目将允许Felicitas Wiedermann女士进行一个三阶段的研究项目，以开发一个有效的协议，从牙釉质中提取气候信息。釉质是一种致密、低孔隙度的结构，在许多考古环境中保存良好，并能抵抗埋葬环境的污染。由于釉质有机成分中的氧和碳最终来自个体（及其母亲）消耗的食物和水，因此它们密切反映了这些物质的同位素比例。独立的和食物结合的水的氧同位素比受到温度和降雨量的影响，这些气候变量因此反映在牙釉质中。碳同位素比率随动物食用的植物类型而变化，釉质碳比率提供了对植被覆盖的深入了解。羊的牙齿，这构成了这项研究的基础上增长的增量，并通过分析的个别部分，可以检查的程度，季节性变化的一年。这些知识为理解史前人类行为提供了环境背景。在一项多阶段的研究中，魏德曼女士希望开发出一种强大的分析方法。在第一阶段，她将喂养实验室绵羊同位素标记的水以及定时生物标记，这将使她能够确定牙齿生长的速度和几何形状。有了这些信息，她将制定一个战略，切片牙齿，以消除时间相关的样本。然后，她将把这项技术应用于近东的现代牙齿。由于这些材料将从已知植被、温度和植被的特定地点获得，因此有可能在同位素比率和这些环境变量之间建立紧密的联系。最后，她将把这项技术应用于约旦艾因加扎勒新石器时代考古遗址的样本。 这将使她能够确定这些古老牙齿在多大程度上受到地面变化的影响，并将该技术直接应用于一个重要的考古问题。这项工作很重要，因为如果成功的话，它将发展一种技术，为史前史学家和其他重建过去的科学家提供有价值的数据。我也将帮助培养一个非常有前途的年轻科学家。

This doctoral dissertation research project will permit MS Felicitas Wiedermann to conduct a three stage research project to develop an effective protocol to extract climatic information from tooth enamel. Enamel is a dense, low porosity structure which is well preserved in many archaeological situations and is resistant to contamination from burial environment. Because the oxygen and carbon in the organic component of enamel ultimately derives from food and water consumed by the individual (and its mother) they closely reflect the isotopic ratio of the materials from which these derive. The oxygen isotope ratio of both freestanding and food-incorporated water is affected by both temperature and amount of rainfall and these climatic variables are thus reflected in tooth enamel. Carbon isotope ratio varies with the type of plants an animal consumes and enamel carbon ratios provide insight into vegetation cover. Sheep teeth, which constitute the basis for this study grow in increments and through analysis of the individual sections one can examine the degree of seasonal change across the year. Such knowledge provides an environmental context for understanding prehistoric human behavior. In a multistage study MS Wiedermann hopes to develop a robust analytic methodology. In the first stage she will feed laboratory sheep isotopically labeled water as well as timed biogenic markers which will permit her to determine the rate and geometry of tooth growth. With this information she will develop a strategy for sectioning teeth to remove chronologically relevant samples. She will then apply this technique to modern teeth from the Near East. Since the materials will be obtained from specific locales where vegetation, temperature and vegetation are known it will be possible to draw tight links between isotope ratios and these environmental variables. Finally she will apply the technique to samples from the Neolithic archaeological site of Ain Ghazal, Jordan. This will allow her to determine the extent to which such ancient teeth are subject to in ground alteration and to apply the technique directly to a significant archaeological question. This work is important because, if successful, it will develop a technique which will provide valuable data to prehistorians and other scientists who reconstruct the past. I will also help to train a very promising young scientist.