Constraints on the Hawaiian Swell and Plume-lithosphere Interaction from Kaua`i Mantle Xenoliths

摘要：0622827（Bizimis）智力价值：这项工作旨在了解拟议热点起源的火山洋岛屿周围浅洋底的起源。 这项工作对于我们理解地幔柱地球动力学、地幔柱如何与岩石圈相互作用以及地幔柱火山活动的起源至关重要。 夏威夷涌浪是这些地区中研究最广泛的地区，也是研究的目标。这项工作测试了两种不同的地球物理岩石圈减薄模型，使用详细的地球化学分析（Hf-Os-Nd-Sr-Pb同位素，微量元素和主要元素浓度）的橄榄岩捕虏体从考艾岛。 化学数据将用于识别太平洋岩石圈和地幔柱中橄榄岩的特征。如果在考艾岛发现与地幔柱有关的和原地太平洋岩石圈成分的橄榄岩，就像在奥陶纪一样，这是夏威夷岛下目前中心下游的地幔柱对太平洋岩石圈进行大规模侵蚀和置换的证据。 来自卡拉岛的稀有石榴辉石岩捕虏体，以及来自瓦胡岛盐湖火山口的具有“镁长岩”前体的石榴辉石岩，它们代表了海洋地幔最深的一些样本，也将进行分析，以尝试识别不同的辉石岩的拟议起源，并将它们识别为回收的洋壳或高压累积岩。 由此产生的工作将提供一个新的和前所未有的，4维（空间和时间）的岩石圈以上的羽状。更广泛的影响：这项研究直接补充其他正在进行的NSF资助的项目，其目标是形象的夏威夷膨胀的根源，并确定通过研究熔岩夏威夷群岛周围的次生火山活动的起源。 结果将以出版物和在国家专业会议上介绍的形式传播。这项研究支持了佛罗里达州立大学的一位早期职业科学家，并将使本科地球科学专业的学生参与与本研究的主要研究目标直接相关的项目。 这项研究还将通过国家高磁场实验室（NHMFL）的NSF资助的REU计划参与和培训本科科学专业，并将通过NHMFL正在进行的外展计划让中学生参与和接触地球科学研究。 更多的公众宣传将发生在每年的NHMFL开放日。

ABSTRACT: 0622827 (Bizimis)Intellectual merit: This work seeks to understand the origin of the shallow ocean floor around volcanic ocean islands of proposed hotspot origin. The work is crucial to our understanding of plume geodynamics, how plumes interact with the lithosphere, and the origin of plume volcanism. The Hawaiian swell, the most extensively studied of these regions, is the research target. The work tests two different geophysical lithosphere thinning models using detailed geochemical analyses (Hf-Os-Nd-Sr-Pb isotopes, trace and major element concentrations) of peridotite xenoliths from the island of Kaua`i. Chemical data will be used to identify the signatures of peridotites from the Pacific lithosphere and from the mantle plume. If peridotites with both plume-related and in situ Pacific lithosphere compositions are found at Kaua`i, as they are in O`ahu, this is evidence for large-scale erosion and replacement of the Pacific lithosphere by the plume downstream from its present center under the island of Hawai'i. Rare garnet pyroxenite xenoliths from Ka`ula island, and garnet pyroxenites with "majorite" precursors from Salt Lake Crater, O`ahu, which represent some of the deepest samples from the oceanic mantle will also be analyzed to try and identify different proposed origins of the pyroxenites, and identify them as either recycled oceanic crust or high pressure cumulates. The resulting work will provided a new and unprecedented, 4-dimensional (space and time) view of the lithosphere above a plume.Broader impacts: This research directly complements other ongoing NSF-funded projects, whose objective is to image the root of the Hawaiian swell and determine the origin of the secondary volcanism around the Hawaiian Islands through the study of lavas. Results will be disseminated in the form of publications and presentations at national professional meetings. The research supports an early career scientist in at Florida State University and will involve undergraduate Earth Sciences majors in projects directly related to the main research objectives of this study. This research will also involve and train undergraduate science majors through a NSF-funded REU program at the National High Magnetic Field Lab (NHMFL), and will involve and expose middle school students to research in earth sciences through ongoing outreach programs at the NHMFL. Additional public outreach will occur at the annual NHMFL Open House.