A Petrologic, Trace Element, and Isotopic Investigation intothe Upper Mantle Xenoliths From Oahu, Hawaii

目前的夏威夷岩浆成因模型假设至少有两个或两个以上同位素和化学性质不同的端元地幔源参与，其中一个是原始热柱，另一个是岩石圈。岩石圈和地幔柱的相对作用在这些模型中一直存在争议，这些模型通常基于喷发熔岩的成分。岩石圈的碎片以捕虏体的形式大量出现在欧胡岛的火奴鲁鲁熔岩中，这为研究夏威夷岩石圈提供了一个窗口，对这些岩石的批判性研究可能有助于解决一些争议。本项目涉及正在进行的瓦胡岛上地幔捕虏体研究的第二阶段，其中包括对根据矿物学和岩石学选择的几种捕虏体（在某些情况下还包括微量元素）的矿物阶段进行详细的同位素和微量元素调查。在本研究的第一阶段，对横贯库劳盾状火山的多个喷口的大量捕虏体进行了岩石学和矿物化学表征。拟议的同位素和微量元素调查，结合较早的岩石学-矿物学研究，有望对岩石圈的性质和使含水相结晶的流体提供深入的了解。水相组成的比较研究。将包体内部和包体之间的成分变化与喷发的Koolau（拉斑岩）和Honolulu（碱性）熔岩进行对比研究，将有助于评估夏威夷岩浆生成模型，并有助于评估热点岩浆活动期间夏威夷岩浆生成和岩石圈-岩浆相互作用过程的模型。//

Current models of Hawaiian magma genesis postulate the involvement of at least two or more isotopically and chemically distinct end member mantle sources, one of which is a primitive hot plume and another one is the lithosphere. The relative roles of the lithosphere and the plume have been a matter of debate in these models, which are generally based on the composition of the erupted lavas. Fragments of the lithosphere occur in abundance as xenoliths in the post-erosional Honolulu lavas of Oahu, which provide a window into the Hawaiian lithosphere, and a critical examination of these rocks may help resolve some of these disputes. The present project is concerned with the second phase of an ongoing study of upper mantle xenoliths from Oahu, which includes a detailed isotopic and trace element investigation into the mineral phases of several xenoliths selected on the basis of their mineralogy and petrography (and, in some cases, trace elements). In the first phase of this research, petrographic and mineral-chemical characterization was carried out on a large number of xenoliths from number of vents that cut across the koolau shield volcano. The proposed isotopic and trace element investigation, in conjunction with the earlier petrographic- mineralogic study, is expected to offer an insight into the nature of the lithosphere and the fluids which have crystallized the hydrous phases. Comparative studies of the compositional the hydrous phases. Comparative studies of the compositional variations within and between xenoliths and the erupted Koolau (tholeiitic) and Honolulu (alkalic) lavas will help evaluate models of Hawaiian magma generation and help evaluate models of Hawaiian magmas generation and lithosphere-magma interaction processes during hot spot magmatism. //