U-Th Systematics of Primitive Icelandic Basalts: Building a Foundation for Interpreting U-Th Disequilibrium in MORBs

9628083辛德勒这项建议对冰岛三个主要地区的橄榄拉斑玄武岩和苦橄岩进行了详细的化学和同位素研究。它将侧重于发展对导致这些岩石中U-Th不平衡程度变化的因素的定量理解。该项目的主要目标是探索和量化熔融深度和源成分的变化对铀-钍不平衡的影响，而不考虑直接调查MORBs所固有的年龄不确定的复杂情况。样本将在项目第一年和第三年早期的田间季节收集。此外，这项研究将利用现有的具有良好特征的样本套件。数据采集的主要阶段将在头两年进行，并对大约75个样品进行详细的同位素和地球化学表征。第二阶段的数据采集将在项目的第三年进行，将侧重于早期工作确定的重要目标。这项调查的结果预计将大大改进U-Th方法作为研究MORBs和其他地幔来源的火山岩的工具的效用。

9628083 Zindler This proposal describes a detailed chemical and isotopic study of olivine tholeiites and picrites from three main localities in Iceland. It will focus on development of a quantitative understanding of the factors that cause variations in the degree of U-Th disequilibrium in these rocks. The principal goal of the project is to explore and quantify the effects of variations in the depth of melting and source composition on U-Th disequlibrium, absent the complications of age-uncertainty inherent in direct investigations of MORBs. Samples will be collected during field seasons early in the first and third years of the project. In addition, the study will make use of existing well-characterized sample suites. The main stage of data acquisition will occur during the first two years and result in detailed isotopic and geochemical characterization of approximately 75 samples. The second stage of data acquisition will occur during the third year of the project, and will focus on important targets identified by the earlier work. The results of this investigation are expected to lead to substantial improvement in the utility of the U-Th method as a tool for studying MORBs and other mantle-derived volcanics.