Petrogenesis of Hawaiian Tholeiites: Constraints from Non-Traditional Stable Isotopes

该奖项将支持一名早期职业研究者研究非传统稳定同位素（一种新型工具）在高温地球化学和岩石学领域的应用。该项目的最终目标是更好地了解夏威夷火山活动的起源。拟议的研究包括教育和培训研究生和本科生最先进的分析技术及其在地球科学中的应用。该项目还将帮助这位早期职业科学家建立一个最先进的实验室，该实验室将支持许多研究人员和学生的研究，不仅在他自己的机构，也在与内华达州高等教育系统联合的其他机构。由该研究员监督的分析地球化学实验室将服务于地球和环境科学的广泛领域，以及作为EPSCoR状态的区域基础设施。最后，拟议的研究将通过使用从以前的NSF资助项目（如夏威夷科学钻探项目）中回收的样本来利用以前的NSF投资。地球的地幔被认为是由富含橄榄石的橄榄岩组成的。然而，某些洋岛玄武岩（OIB）的主要元素特征，如夏威夷熔岩，不能由橄榄岩的部分熔融产生。关于夏威夷熔岩中SiO2的变化，人们提出了多种模型，包括熔融-地幔反应模型、英安岩岩浆模型和次生辉石岩模型。在全球范围内，夏威夷熔岩定义了OIB组成同位素谱的高sio2端元。因此，了解夏威夷熔岩中SiO2变化的起源对于了解全球oib的岩石成因具有重要意义。来自莫纳克亚山、库劳和卡霍奥拉维的熔岩定义了夏威夷熔岩组成同位素谱的两个末端成员。为了解决这个问题，研究者建议对莫纳克亚火山和卡霍奥拉维火山的镁和铁同位素进行详细而系统的研究。对库劳熔岩的镁、铁、钙同位素组成进行了广泛的研究。这项工作扩展了正在进行的对这些样品的钙同位素组成的研究。本文认为，基于Ca、Mg和Fe等主要元素的非传统稳定同位素研究可能为夏威夷熔岩的组成和同位素变化提供线索。在未来，这种方法可以应用于全球的oib，以限制它们的岩石成因。

This award will support an early career investigator to study the application of non-traditional stable isotopes, a novel tool, in the fields of high-temperature geochemistry and petrology. The ultimate goal of the project is to better understand the origin of Hawaiian volcanism. The proposed research involves educating and training graduate and undergraduate students in state-of-the-art analytical techniques and their applications to geosciences. The project will also help this early-career scientist build a state-of-the art laboratory that will support the research of a number of researchers and students not only at his own institution but also in other institutions allied to the Nevada System of Higher Education. The analytical geochemistry laboratory overseen by this investigator will serve a broad area of earth and environmental sciences, as well as to serve as regional infrastructure in an EPSCoR state. Finally, the proposed research will leverage previous NSF investments by using samples recovered from previous NSF funded programs, such as Hawaii Scientific Drilling Project.The Earth's mantle is thought to be composed of olivine-rich peridotite. However, the major element characteristics of some ocean island basalts (OIB), such as some Hawaiian lavas, cannot be produced by partial melting of peridotite. A variety of models have been suggested to explain the SiO2 variation in Hawaiian lavas, including melt-mantle reaction model, dacite magma model, and secondary pyroxenite model. On a global scale, Hawaiian lavas define the high-SiO2 endmember of the OIB compositional-isotopic spectrum. Consequently, understanding the origin of SiO2 variation within Hawaiian lavas is important in understanding the petrogenesis of global OIBs. Lavas from Mauna Kea, Koolau and Kahoolawe define two endmembers of the compositional-isotopic spectrum of Hawaiian lavas. The investigator proposes a detailed and systematic Mg and Fe isotopic study of Mauna Kea and Kahoolawe lavas to resolve this question. Koolau lavas have been extensively studied for Mg, Fe and Ca isotopic compositions. This effort expands on an ongoing study of the Ca isotopic compositions of these samples. It is suggested that non-traditional stable isotopic studies based on major elements such as Ca, Mg, and Fe may provide clues as to the nature of the compositional and isotopic variations shown in Hawaiian lavas. In the future, such approach can be applied to global OIBs to constrain their petrogenesis.