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

夏威夷拉斑玄武岩的岩石成因：非传统稳定同位素的制约

• 批准号: 1524387
• 负责人: Shichun Huang
• 金额: $ 24.98万
• 依托单位: University of Nevada Las Vegas
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1524387&HistoricalAwards=false
• 关键词: Petrogenesis; Hawaiian; Tholeiites; Constraints; Non

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.

该奖项将支持早期职业研究者研究非传统稳定同位素的应用，这是一种新型工具，在高温地球化学和岩石学领域。该项目的最终目标是更好地了解夏威夷火山的起源。拟议的研究涉及以最先进的分析技术及其对地球科学的应用教育和培训毕业生和本科生。该项目还将帮助这位早期的科学家建立一个最先进的实验室，该实验室将不仅在他自己的机构中，而且在与内华达州高等教育体系相关的其他机构中的许多研究人员和学生的研究。该研究人员监督的分析地球化学实验室将为地球和环境科学领域提供广泛的领域，并在EPSCOR州充当区域基础设施。最后，拟议的研究将利用从以前的NSF资助计划（例如夏威夷科学钻探项目）中回收的样品来利用先前的NSF投资。地球的地幔被认为是由富含橄榄石的橄榄石组成的。但是，某些海洋岛玄武岩（OIB）的主要元素特征（例如某些夏威夷熔岩）不能通过橄榄岩的部分熔化而产生。已经提出了各种模型来解释夏威夷熔岩中的SiO2变化，包括熔体隐形反应模型，dacite岩浆模型和次生辉石模型。在全球范围内，夏威夷熔岩定义了OIB组成 - 异位谱的高sio2末端。因此，了解夏威夷熔岩中SIO2变化的起源对于理解全球OIB的石油形成很重要。来自Mauna Kea，Koolau和Kahoolawe的熔岩定义了夏威夷熔岩的组成 - 异位谱的两个末端。研究人员提出了Mauna Kea和Kahoolawe熔岩的详细而系统的MG和FE同位素研究，以解决这个问题。 Koolau熔岩已被广泛研究用于MG，Fe和Ca同位素组合物。这项工作扩大了对这些样品的CA同位素组成的持续研究。有人认为，基于CA，MG和FE等主要元素的非传统稳定同位素研究可能会提供有关夏威夷熔岩中显示的组成和同位素变化性质的线索。将来，这种方法可以应用于全球OIB，以限制其岩石发生。

项目成果

Equilibrium inter-mineral titanium isotope fractionation: Implication for high-temperature titanium isotope geochemistry

• DOI: 10.1016/j.gca.2019.11.008
• 发表时间: 2020-01
• 期刊: Geochimica et Cosmochimica Acta
• 影响因子: 5
• 作者: Wenzhong Wang;Shichun Huang;F. Huang;Xinmiao Zhao;Zhongqing Wu