Characterization of the Effects of Diffusive Reequilibration on the Compositions of Olivine-Hosted Melt Inclusions

该项目的目标是（1）确定一旦被纳入橄榄石熔融包裹体中，其浓度保持不变的元素，以及（2）量化包裹后结晶的量，该结晶通常被橄榄石中Fe和Mg的扩散再平衡所“擦除”。 这些目标将通过以下方式实现：（1）通过实验确定所选微量元素的扩散系数（2）通过实验确定了橄榄石中微量元素（Al，Ti）的矿物-熔体分配体系，以及（3）将实验结果与邻近熔融包裹体的橄榄石的二次离子质谱研究相结合，以识别和表征缓慢扩散的次要或痕量元素的浓度梯度，从包埋后结晶。在这个实验和分析研究的过程中收集的数据将提供一个更好的理解后包埋结晶和扩散再平衡的橄榄石托管熔融包裹体的主要元素成分的影响，增加其价值的地球化学信息的来源熔体生成和提取的过程中的地球上地幔。

GaetaniEAR-0087525The objectives of this project are (1) to identify elements whose concentrations are conserved once incorporated into an olivine-hosted melt inclusion, and (2) to quantify the amount of post-entrapment crystallization that is typically "erased" by diffusive reequilibration of Fe and Mg in the host olivine. These goals will be achieved by (1) determining experimentally the diffusivities of select minor elements (Ca, Al, Ti) in magnesian olivine, (2) determining experimentally themineral-melt partitioning systematics of elements present in olivine as minor constituents for which there is currently very little data (Al, Ti), and (3) combining the experimental results with a secondary ion mass spectrometry study of the olivine adjacent to melt inclusions to identifyand characterize concentration gradients in slow diffusing minor or trace elements that result from post-entrapment crystallization. The data collected over the course of this experimental and analytical study will provide a better understanding of the effects of post-entrapment crystallization and diffusive reequilibration on the major element compositions of olivine-hosted melt inclusions, increasing their value as sources of geochemical information about the processes of melt generation and extraction in the upper mantle of the Earth.