Boron Isotopic Studies of Subduction Zone Processes

硼同位素比率将被证明有助于澄清来源 B和它被纳入弧岩浆的过程。 这个项目是要分析一些火山的玄武熔岩 弧建立与俯冲等因素的相关性， 速率、热状态、几何形状等。 来自板块内部环境的熔岩（海洋岛屿和扩张 中心）进行分析，以更好地确定B同位素 不受俯冲影响的地幔区域的组成。 此外，还计划分析来自两个渐进式 同位素分馏效应评价 伴随脱水和重结晶。 拟议工作 与流体-岩石相互作用和物质输运的研究有关 通过热液卤水，对与俯冲有关的 热液矿物演化的研究 矿床及其变质作用对挥发分的影响 地壳岩石。

Boron isotopic ratios will prove useful in clarifying the source of B and the processes by which it is incorporated into arc magmas. This project is to analyze basaltic lavas from a number of volcanic arcs to establish correlations with such factors as subduction rates, thermal state, geometry, etc. For comparison, selected lavas from within-plate settings (Ocean islands and spreading centers) will be analyzed to better define the B isotopic composition of mantle regions that are unaffected by subduction. Also it is planned to analyze samples from two progressive metamorphic suites to evaluate isotopic fractionation effects accompanying dehydration and recrystallization. The proposed work is relevant to studies of fluid-rock interaction and mass transport via hydrothermal brines, to tracer studies of subduction-related processes, and to studies of the evolution of hydrothermal mineral deposits and effects of prograde metamorphism on devolatilization of crustal rocks.