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

在这份合同中，研究人员将对ALVIN收集的样本和其他船只从马里亚纳海槽和劳盆地的扩张轴上挖掘的样本进行Nd、Sr和Pb同位素研究，这两个地区都是西太平洋非常重要的后弧盆地。这两组样品非常有价值，因为它们是以非常精细的尺度和巨大的成本收集的，并且在样品地点进行了大量的地球物理测量。此外，ALVIN样品还存在目视观测资料。主要元素和微量元素分析正在对这些样品进行，作为其他NSF支持项目的一部分。元素和同位素组合数据将有助于认识边缘盆地岩浆源变异性的性质和规模、岩石的部分熔融和岩浆混合、扩张脊的分割等岩浆过程。该研究还将表明这些弧后盆地下地幔的不均匀程度。弧后盆地在一定程度上被学界所忽视，但它们为全面认识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. //