Marginal Basin Basalts: Isotopic Studies Bearing on Magma Genesis and Source Evolution

在这个奖项中，调查人员将对Alvin收集的、由其他船只从马里亚纳海槽和刘盆地的扩张轴上疏浚的样品进行Nd锶和Pb3+同位素研究，这两个盆地都是西太平洋非常重要的弧后盆地。这两套样本非常有价值，因为它们是以非常精细的规模和巨大的成本收集的，而且在样本地点进行了大量的地球物理测量。此外，阿尔文样品还存在目视观测数据。作为美国国家科学基金会资助的其他项目的一部分，正在对这些样品进行主要元素和微量元素分析。元素和同位素数据的结合将有助于了解边缘盆地中各种岩浆作用的性质和规模，如岩浆源区变异性的性质和规模、岩石的部分熔融和岩浆的混合、扩张脊的分段等，并将揭示这些弧后盆地地幔的不均匀程度。弧后盆地在某种程度上被社区忽视了，但它们为全面了解板块构造过程提供了重要线索。//

In this award, the investigators would carry out a Nd, Sr, and Pb isotopic study of samples collected by ALVIN and dredged by other ships from the spreading axes in the Mariana Trough and the Lau Basin, both very important back arc basins in the western Pacific. These two sample sets are extremely valuable since they were collected at a very fine scale and at a great cost and considerable geophysical measurements were made at the sample sites. Besides, visual observational data exist with the ALVIN samples. Major element and trace element analyses are being done on these samples, as part of other NSF supported projects. The combined elemental and isotopic data set will help in understanding various magmatic processes in marginal basins, such as, nature and scale of source variability of magma, partial melting of rocks and mixing of magma, segmentation of the spreading ridge, etc. Also the study will indicate the extent of inhomogeneity in the mantle under these back arc basins. Back arc basins have been somewhat neglected by the community but they hold important clues for the overall understanding of the plate tectonic processes. //