Geochemical Evolution of Samoan Shield Volcanoes

本项目是对两个萨摩亚盾状火山的玄武岩和分化熔岩进行地球化学和同位素研究。这将是对萨摩亚盾状火山的全面化学地层学的第一次系统评价，并将与夏威夷和塔希提岛以这种方式研究的几座火山进行重要的比较。这项研究可以利用现有收集的样本来完成，但是项目事务处也有机会在1991年9月进行一些额外的抽样和实地研究。这项工作的重点是在微量元素数据的基础上，获得20-25个额外样本的新的同位素数据，并在整个熔岩组成范围内获得一套急需的稀土丰度。这些数据对于与离子探针对萨摩亚超镁质捕虏体中的斜辉石和熔岩斑晶所获得的分析结果进行比较尤其重要。该奖项还将允许朱莉·迪欧在斯克里普斯研究所完成博士论文。

This project is for a geochemical and isotopic study of basalts and differentiated lavas of two Samoan shield volcanoes. This will be the first systematic evaluation of the full chemical stratigraphy of a Samoan shield volcano, and will provide an important comparison to several volcanoes studied in this way in Hawaii and Tahiti. The study can be accomplished using samples already in existing collections, but the PIs also have the opportunity to carry out some additional sampling and field studies in September, 1991. The effort will focus on obtaining new isotopic data on 20-25 additional samples selected on the basis of trace-element data, and acquisition of a much needed set of rare-earth abundances throughout the range of lava compositions. These will be particularly important to compare to analyses obtained by ion microprobe on clinopyroxenes in Samoan ultramafic xenolith and on lava phenocrysts. This award will also allow completion of a doctoral dissertation at Scripps Institution by Julie Dieu.