Collaborative Research: Chemical, Isotopic and Volatile Constraints on the Evolution of the Lau Basin

合作研究：化学、同位素和挥发物对劳盆地演化的限制

• 批准号: 0453138
• 负责人: Barry Hanan
• 金额: --
• 依托单位: San Diego State University Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0453138&HistoricalAwards=false
• 关键词: Collaborative; Research; Chemical; Isotopic; Volatile

Intellectual MeritThis research supports four investigators at two southern California universities to carry out a comprehensive geochemical and isotopic investigation of magmatic processes occurring in the Lau back-arc basin in the western Pacific. The setting is an ideal one to study and understand links between subducting oceanic crust and its sediment cover, back-arc mantle dynamics, and heterogeneity as well as the mantle source of magmas erupting along the arc and on the seafloor. This work seeks to characterize the geochemistry of the mantle beneath the basin and discern its control on basin evolution. In particular, the research will focus on understanding how the composition of the ocean crust in the Lau Basin in the western Pacific Ocean is affected by materials coming from the Pacific plate that is being subducted to the east. The Lau Basin has been a site of intense reconnaissance work and the targeted geochemical sample suite consists of 400 lavas and glasses collected by Scripps Institution of Oceanography during five NSF-sponsored cruises to the region. The sample inventory represents extensive coverage of the Lau Basin, including lavas from all recognized spreading centers. This research will analyze representative igneous and volcanic rocks for major and trace element chemistry (including REE, HFSE, and light elements Li, Be, B, Cl); volatile elements (CO2, H2O); isotopes of Sr, Nd, Pb, Hf, He, Ne, and Ar; and short-lived isotopes of the U decay series (226Ra, 230Th, and 234U). With this unprecedented data set, the research will be able to address the following four issues: (1) whether it is possible to map the spatial distribution and extent of Indian- and Pacific-type mantles in the Lau Basin; (2) what the spatial extent of the Samoan mantle plume component in the Lau Basin is; (3) how the proximity of the Lau Basin spreading centers to the Tofua Arc affects mantle melting, and (4) what proportion of volatile enrichment in Lau Basin lavas is due to ridge-arc source interaction versus other processes such as crustal assimilation. This work will provide the framework for additional work in the region. The work is important for the science objectives of the NSF-funded MARGINS and RIDGE 2000 Programs. Broader Impacts: Broader impacts of this research include contributions to education and training of at least three graduate students (Ph. D. and/or M.S). Furthermore, undergraduates will be involved in selected aspects of the work. Students will receive broad geochemical training in a number of sub-disciplines of analytical geochemistry. In addition the presence of PhD-level students from the University of California, San Diego (UCSD) at San Diego State University (SDSU), which has no PhD program, will stimulate and challenge the undergraduate and Master's students to higher levels of achievement. Finally, the proposal will help to support the considerable analytical infrastructure at UCSD and SDSU, as well as foster closer working relationships between faculty and students at both institutions.

知识分子的研究支持南加州两所大学的四名研究人员，对西太平洋的LAU后弧盆地发生的岩浆过程进行全面的地球化学和同位素研究。该设置是研究和理解俯冲的海洋壳及其沉积物覆盖物，后弧形的动力学和异质性以及沿弧线和海底爆发岩浆的地幔的理想环境。这项工作旨在表征盆地下地幔的地球化学，并辨别其对盆地进化的控制。 特别是，该研究将集中于了解西太平洋刘盆地中海角的成分如何受到来自太平洋板块的材料的影响，而太平洋板块是向东俯冲的。 Lau盆地一直是强烈侦察工作的地点，目标地球化学样品套件由Scripps海洋学研究所收集的400个熔岩和玻璃组成，该机构在五次NSF赞助的巡游到该地区。样品清单代表了Lau盆地的广泛覆盖范围，包括来自所有公认的扩展中心的熔岩。 这项研究将分析主要和痕量元素化学（包括REE，HFSE和Light Elements Li，be，b，cl）的代表岩石和火山岩；挥发性元素（CO2，H2O）; SR，ND，PB，HF，HE，NE和AR的同位素；以及U型衰减系列的短期同位素（226ra，230th和234u）。 通过此前所未有的数据集，该研究将能够解决以下四个问题：（1）是否可以绘制Lau盆地印度和太平洋型披风的空间分布和程度； （2）Lau盆地中萨摩亚地幔羽状成分的空间范围是什么； （3）LAU盆地在豆腐弧中扩散中心的接近性会影响地幔熔化，以及（4）lau盆地熔岩中的挥发性富集的比例是由于山脊 - arc源相互作用而引起的，而其他过程与其他crust型同化（例如甲壳同化）。 这项工作将为该地区的其他工作提供框架。 这项工作对于NSF资助的边距和Ridge 2000计划的科学目标很重要。更广泛的影响：这项研究的更广泛影响包括至少三名研究生的教育和培训（博士学位和/或M.S）的贡献。此外，本科生将参与工作的某些方面。学生将接受广泛的地球化学培训，这些培训在许多分析地球化学的子学科。 此外，来自没有博士学位课程的圣地亚哥州立大学（SDSU）的加利福尼亚大学圣地亚哥分校（UCSD）的博士学位学生将刺激和挑战本科生和硕士的学生提高成就水平。 最后，该提案将有助于支持UCSD和SDSU的大量分析基础架构，并在这两个机构的教职员工和学生之间建立更紧密的工作关系。