Isotopic and Trace Element Studies of the Lithospheric Mantle, Petrogenetic Processes and Magma Transport, & the Early Stages of Continental Crust Formation

岩石圈地幔的同位素和微量元素研究、岩石成因过程和岩浆输送，

• 批准号: 8916858
• 负责人: J. Douglas Macdougall
• 金额: $ 40.17万
• 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: 1990
• 资助国家: 美国
• 起止时间: 1990-04-01 至 1994-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8916858&HistoricalAwards=false
• 关键词: Isotopic; Trace; Element; Studies; Lithospheric

This a proposal to continue and expad our isotopic and trace element studies of a variety of mantle and mantle-derived rocks as tracers of the composition and evolution of the lithosphere and upper mantle, and of petrogenetic processes such as melting and magma transport. Our work is centered around isotopic studies of Sr, Nd and Pb on the one hand and U, Th series isotopes on the other, and the associated trace element concentrations which are measured in concert with the isotope ratio determinations. In addition, we discuss plans to add a number of important large ionic radius and high field strength elements to our capabilities using ICP-MS. Our investigations are varied and have both regional and more uniersal goals. In the most general sense, the work proposed is inteded to further our knowledge of the composition and evolution of the lithosphere anduppermost mantle in both continental and oceanic settings, and to help nderstand factors such as the timing of magma transport and the mechanisms of chemical fractionation during magmagenesis. Using isotopes as tracers we will also attempt to follow the earliest stages of continental crust formation in an accreting island arc terrane. Specific material we will investigate in pursuit of these goals incluse lavas from the Sylhet and Deccan Traps of India; mantle xenoliths from alkali basalts in Incia, China, Western North America and oceanic islands in the South Pacifice; a sequence of plutonic rocks from Luzon in the Philippines; island arc lavas from the Aleutians, ridge basalts from the Pacific and the Mariana Trough back arc basin.

本文建议继续并扩大我们对各种地幔和幔源岩石的同位素和微量元素的研究，作为岩石圈和上地幔的组成和演化的示踪剂，以及熔融和岩浆运输等岩石形成过程的示踪剂。我们的工作主要集中在Sr、Nd和Pb的同位素研究和U、Th系列同位素的研究，以及与同位素比值测定相一致的相关微量元素浓度的测量。此外，我们还讨论了使用ICP-MS增加一些重要的大离子半径和高场强元素的计划。我们的调查是多种多样的，既有区域性的目标，也有更普遍的目标。在最一般的意义上，提出的工作旨在进一步了解大陆和海洋环境下岩石圈和上地幔的组成和演化，并有助于理解岩浆运输的时间和岩浆作用过程中化学分馏的机制等因素。使用同位素作为示踪剂，我们还将尝试在一个增生岛弧地体中跟踪大陆地壳形成的最早阶段。为了实现这些目标，我们将研究的具体材料包括来自印度锡尔赫特和德干圈闭的熔岩；来自印度、中国、北美西部和南太平洋海洋岛屿的碱性玄武岩的地幔捕虏体；菲律宾吕宋岛的一组深成岩；来自阿留申群岛的岛弧熔岩，来自太平洋的脊玄武岩和马里亚纳海槽弧后盆地。