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

摘要：0622827(Bizimis)智力价值：这项工作试图了解火山洋岛周围浅海底的起源，这些岛屿被认为是热点起源。这项工作对我们理解羽流地球动力学、羽流如何与岩石圈相互作用以及羽流火山作用的起源至关重要。夏威夷隆起是这些地区中研究最广泛的，也是研究的对象。这项工作通过对考阿岛橄榄岩包体进行详细的地球化学分析(Hf-Os-Ndsr-Pb同位素、痕量和常量元素浓度)来检验两种不同的地球物理岩石圈减薄模型。化学数据将被用来识别来自太平洋岩石圈和地幔热柱的橄榄岩的特征。如果在考阿伊发现具有与岩浆有关的和原地太平洋岩石圈成分的橄榄岩，就像在欧阿胡发现的那样，这是太平洋岩石圈大规模侵蚀和被夏威夷岛下目前中心下游的羽流取代的证据。来自卡瓦拉岛的稀有石榴石辉石岩包体，以及来自欧胡盐湖陨石坑的石榴石辉石岩，代表了大洋地幔最深的一些样品，也将被分析，以尝试和识别辉石岩的不同来源，并确定它们是再循环洋壳或高压堆积体。由此产生的工作将提供一种新的、史无前例的、垂直上方岩石圈的4维(空间和时间)视角。广泛的影响：这项研究直接补充了其他正在进行的NSF资助的项目，这些项目的目标是通过对熔岩的研究来成像夏威夷膨胀的根源，并确定夏威夷群岛周围次级火山活动的起源。结果将以出版物和在国家专业会议上介绍的形式传播。这项研究支持佛罗里达州立大学的一名早期职业科学家，并将让地球科学专业的本科生参与与这项研究的主要研究目标直接相关的项目。这项研究还将通过NSF资助的国家高磁场实验室(NHMFL)的REU计划，让本科生参与并培训他们，并通过NHMFL正在进行的推广计划，让中学生参与地球科学的研究。额外的公众宣传将在一年一度的NHMFL开放日上进行。

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.