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人员研究非传统稳定同位素，一种新工具，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。拟议的研究涉及教育和培训研究生和本科生在国家的最先进的分析技术及其应用于地球科学。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，不仅支持他自己的机构，而且还支持与内华达州高等教育系统结盟的其他机构的研究人员和学生的研究。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，并作为EPSCoR状态的区域基础设施。最后，拟议中的研究将利用美国国家科学基金会以前的投资，使用从以前的美国国家科学基金会资助的项目，如夏威夷科学钻探项目回收的样品。然而，一些洋岛玄武岩（OIB）的主要元素特征，如一些夏威夷熔岩，不能产生橄榄岩的部分熔融。夏威夷熔岩中SiO2的变化有多种解释模式，包括熔融-地幔反应模式、英安岩岩浆模式和次生辉石岩模式。在全球范围内，夏威夷熔岩定义的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的岩石成因非常重要。莫纳克亚火山、库劳火山和卡霍奥拉维火山的熔岩定义了夏威夷熔岩成分同位素谱的两个端元。研究人员提出了一个详细的和系统的镁和铁同位素研究莫纳克亚和Kahoolawe熔岩来解决这个问题。 库劳熔岩的Mg、Fe和Ca同位素组成已被广泛研究。这项工作扩大了正在进行的研究，这些样品的钙同位素组成。有人建议，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为夏威夷熔岩中所示的成分和同位素变化的性质提供线索。在未来，这种方法可以应用于全球OIB，以限制其岩石成因。

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