Collaborative Research: Insights into plume-lithosphere interactions from Hawaiian mantle xenoliths

这项研究将包括岩石学工作、矿物化学分析（主要和微量元素），以及对瓦胡岛檀香山火山（HV）侵蚀后尖晶石橄榄岩和石榴石“辉石岩套”捕虏体中矿物分离物的Hf、Os、Sr、Pb和Nd同位素研究。捕虏体来自三个火山口：位于库劳火山边缘的盐湖火山口（SLC）；Kaau和Pali喷口位于火山口附近。该奖项的首要目标是利用同位素和矿物化学信息的结合推断捕虏体的起源。捕虏体上的同位素信息和矿物热气压测量将允许pi识别可能由夏威夷羽流带来的物质类型（俯冲地壳和地幔甚至下地幔或过渡带物质），而不是那些具有岩石圈起源的物质。这项研究将提供对瓦胡岛下浅层地幔同位素变化的直接洞察，而不管它们是来自地幔柱、岩石圈，还是地幔柱、岩石圈或软流圈衍生成分的混合产物。一旦确定了这些，现有的夏威夷火山活动和岩石圈过程模型可能会被微调，或者可能会提出更好的模型。

This study will involve petrographic work, mineral chemical analysis (major and trace elements), and Hf, Os, Sr, Pb, and Nd isotope study of mineral separates from spinel peridotite and garnet "pyroxenite suite" xenoliths from the post-erosional Honolulu Volcanics (HV) of Oahu. The xenoliths come from three vents: Salt Lake crater (SLC) is located on the rim of the Koolau volcano; and Kaau and Pali vents are located close to its caldera. The first order goal under this award is to infer xenolith origins using the combined isotopic and mineral chemical information. The isotopic information and mineral thermobarometry on the xenoliths will allow the PIs to recognize the types of materials (subducted crust and mantle or even lower mantle or transition zone materials) that may have been brought up by the Hawaiian plume versus those that have a lithospheric origin. The study will offer a direct insight into the isotopic variability of the shallow mantle beneath Oahu irrespective of their origin in the plume, the lithosphere, or as a mixed product of plume, lithosphere or asthenosphere- derived components. Once these are identified, existing models on Hawaiian volcanism and lithospheric processes may be fine-tuned or better models may be proposed.