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: 0453608
• 负责人: David Hilton
• 金额: --
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 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=0453608&HistoricalAwards=false
• 关键词: Collaborative; Research; Chemical; isotopic; volatile

ABSTRACT (Hilton - 0453608)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.

摘要（希尔顿- 0453608）学术价值这项研究支持四名研究人员在两个南部加州大学进行全面的地球化学和同位素调查岩浆过程发生在西太平洋劳弧后盆地。这一背景是研究和了解俯冲洋壳及其沉积物盖层、弧后地幔动力学和不均匀性之间的联系以及沿着弧和海底喷发的岩浆的地幔来源的理想背景。这项工作旨在描述盆地下地幔的地球化学特征，并识别其对盆地演化的控制。 特别是，研究将侧重于了解西太平洋Lau盆地的洋壳成分如何受到来自太平洋板块向东俯冲的物质的影响。Lau盆地一直是一个紧张的勘察工作地点，目标地球化学样本套件由斯克里普斯海洋学研究所在美国国家科学基金会赞助的五次对该地区的巡航中收集的400个熔岩和玻璃组成。样本清单代表了劳盆地的广泛覆盖范围，包括来自所有公认的扩张中心的熔岩。 本研究将分析代表性火成岩和火山岩的主要和微量元素化学（包括REE、HFSE和轻元素Li、Be、B、Cl）;挥发性元素（CO2、H2O）; Sr、Nd、Pb、Hf、He、Ne和Ar的同位素;以及U衰变系列的短寿命同位素（226 Ra、230 Th和234 U）。 有了这一前所未有的数据集，这项研究将能够解决以下四个问题：（1）是否有可能绘制Lau盆地印度和太平洋型地幔的空间分布和范围;（2）Lau盆地萨摩亚地幔柱成分的空间范围是什么;（3）Lau盆地扩张中心与Tofua弧的接近程度如何影响地幔熔融，Lau盆地熔岩中挥发分富集的比例是由于脊弧源相互作用还是其他过程如地壳同化作用。 这项工作将为该区域的其他工作提供框架。 这项工作对于NSF资助的MARGINS和RIDGE 2000计划的科学目标非常重要。更广泛的影响：这项研究的更广泛的影响包括对至少三名研究生（博士）的教育和培训的贡献。和/或MS）。此外，本科生将参与工作的选定方面。学生将在分析地球化学的一些子学科中接受广泛的地球化学培训。 此外，圣地亚哥州立大学（SDSU）没有博士课程的加州大学圣地亚哥分校（UCSD）的博士生将激励和挑战本科生和硕士生取得更高水平的成就。 最后，该提案将有助于支持UCSD和SDSU的大量分析基础设施，并促进这两个机构的教师和学生之间更密切的工作关系。