Earth Sciences Postdoctoral Research Fellowship Award

来自夏威夷一套同生玄武岩的EAR-9505215 Lassiter，John C.Re-Os同位素数据将用于提高对Re和Os在地幔熔融和熔体通过地壳运输过程中行为的理解。由于测量极低浓度物质中Re和Os丰度的分析困难，直到最近几年，才有可能考虑将Re-Os系统学应用于地幔对流和地壳演化问题。与目前用于解决这些基本问题的其他同位素系统不同，Os在熔化过程中表现出相容的行为。因此，187Os/186Os比值对演化和原始物质的相对贡献极为敏感。该项目将(1)限制Os(和Re)在熔体生产过程中的化学行为；(2)记录熔体在向地表输送过程中与周围地幔和地壳的相互作用；以及(3)确定玄武岩中Os同位素不均匀的程度及其与可能的地幔不均匀的关系。在理解Re-Os系统学方面的这些进展将使它们能够用于促进对地幔演化的整体理解。

EAR-9505215 Lassiter, John C. Re-Os isotopic data from a suite of cogenetic basalts from Hawaii will be used to improve understanding of the behavior of Re and Os during melting of the mantle and melt transport through the crust. Because of the analytical difficulties in measuring Re and Os abundances in very low-concentration materials, it is only in the past few years that it has been possible to consider application of Re-Os systematics to problems of mantle convection and crustal evolution. Unlike other isotopic systems currently used to address these fundamental problems, Os behaves compatibly during melting. As a result, 187Os/186Os ratios are extremely sensitive to relative contributions of evolved and primitive materials. This project will (1) constrain the chemical behavior of Os (and Re) during melt production; (2) document the interaction of melts with the surrounding mantle and crust during transport to the surface; and (3) determine the degree of Os isotopic heterogeneity in the basalts and the relationship to possible mantle heterogeneities. These advances in the understanding of Re-Os systematics will permit their use in advancing the overall understanding of mantle evolution.