Rock Coring Koolau Volcano, Hawaii: Implications for Deep Mantle Recycling of the Crust

地幔柱中的玄武岩提供了地幔组成和历史的基本信息。夏威夷羽流是地幔羽流的典型例子，它的玄武岩无疑是所有羽流中研究得最好的一组。夏威夷库劳火山的熔岩属于海洋岛玄武岩的一个独特的组成端部，似乎为地壳（沉积物和玄武岩）的深层地幔再循环提供了强有力的证据，尽管这种解释仍然存在争议，并且只基于火山最上层的表面取样。该方案要求拨款从一个245米深的水观测孔的底部获得300米深的岩心。从这口井中取出的岩石将延伸到火山的任何表面暴露之下，预计获得的岩石将比表面岩石经历更少的热带风化。在这个为期一年的项目中，我们将按照为夏威夷科学钻探计划开发的程序系统地描述井中的芯片和岩心，并对岩心和芯片进行初步的岩石学和地球化学表征。

Basalts from mantle plumes provide fundamental information on the composition and history of the Earth's mantle. The Hawaiian plume is the classic example of a mantle plume and its basalts are unquestionably the best studied suite from any plume. The lavas of Koolau Volcano in Hawaii belong to a distinct compositional endmember of ocean island basalts and appear to provide the strong evidence for deep mantle recycling of crust (sediment and basalt), although this interpretation remain controversial and is based on sampling only the uppermost veneer of the volcano. This proposal requests funding to obtain ~300 m of rock core from the base of a ~245 m deep, water observation hole. The rocks from this well will extend below any surface exposures of the volcano and it is expected that the rocks obtained will have experienced less tropical weathering than surface rocks. We will systematically describe the chips and cores from the well following procedures we have developed for the Hawaii Scientific Drilling Program and make an initial petrographic and geochemical characterization of the core and chips for this one year project.