In-Situ Pb Isotope Analysis of Olivine-Hosted Melt Inclusions in MORB

来自大西洋中脊(MAR)地球化学异常段的大洋中脊玄武岩(MORBs)中橄榄石寄主熔体包裹体的铅同位素分析推荐项目，目的是检查MORB源地幔化学不均一性的来源、幅度和标度长度。分析将通过一种创新的新技术进行，使用离子微探针来分析大小为40微米或更大的熔体，检查出现在单个橄榄石晶体、单个样品和单个脊段内的熔体包裹体同位素不均一性。将从一些单独的熔岩中分析大约50个熔体包裹体，以检查流动内的不均质性。待分析的样品位于MAR北纬12-16度之间，寄主样品中存在一系列铅同位素组成，包括熔体包裹体成分显示出极大多样性的单个样品。这些数据将被用来测试和校准与MAR等缓慢扩张山脊相关的地幔融化和熔体输送模型。

Recommended project for Pb isotopic analysis of olivine-hosted melt inclusions from mid-ocean ridge baslats (MORBs) from a geochemically anomalous segment of the Mid-Atlantic Ridge (MAR), with a goal of examining the origin, amplitude, and scale lengths of chemical heterogeneity of the MORB source mantle. Analysis will occur by an innovative, new technique using the ion microprobe to analyze melt inculsions that are 40 um or large in size, examining melt inclusion isotopic heterogeneity that occurs within individual olivine crystals, within individual samples, and within an individual ridge segment. About 50 melt inclusions will be analyzed from a number of individual lavas to examine within-flow heterogeneity. The samples to be analyzed are from 12-16 degrees N on the MAR, where a range of PB isotopic composition occurs in host samples, and include individual samples showing great diversity in their melt inclusions compositions. This data will be used to test and calibrate models of mantle melting and melt transport associated with slow spreading ridges such as the MAR.