US-United Kingdom Cooperative Research: The Role of Boron in the Magma-Vapor Evolution of Granitic Systems in Cornwalland Devon, England

该奖项将支持俄克拉荷马大学的David London博士和英国曼彻斯特大学地质系的D.A.Manning博士和C.M.Henderson博士之间的合作研究。联合研究将集中在1)康沃尔花岗岩系统中岩浆到热液的转变，2)硼和氟在熔体-蒸汽演化和金属迁移与沉积中的作用，以及(3)浅侵位花岗岩/云英岩系统(如康沃尔)与较深的花岗岩/伟晶岩相当物之间关系的一般模拟。英格兰西南部康沃尔和德文郡的花岗岩及其伴生伟晶岩、辉长岩和锡铜矿化云英岩被认为是一种全球类型的分异硅质岩浆作用和伴生的热液成矿作用。从科学和经济的角度来看，这些花岗岩的后期演化，特别是熔融-蒸汽平衡的时间和成分方面，代表了岩浆作用的一个至关重要的阶段。在康沃尔花岗岩系统的挥发性或助熔剂成分中，硼的作用可能是最重要的，也是最不被了解的。拟议的工作将记录该环境中硼(如电气石)的丰度和地质组合，并将研究电气石的流体包裹体，以独特地揭示花岗岩及其伴生脉体和围岩中产生的流体的成分和物理状态。这项研究的结果将与首席研究员开发的实验和理论模型相结合，以进一步阐明硼的地球化学循环。

This award will support collaborative research between Dr. David London, University of Oklahoma and Drs. D. A. Manning and C.M. Henderson, Department of Geology, University of Manchester, England. The joint study will focus on 1) the magmatic to hydrothermal transition in the Cornish granite systems, 2) the roles of boron and fluorine in melt-vapor evolution and metal transport and deposition, and (3) general modeling of the relations between shallowly emplaced granite/greisen sytems (e.g., Cornwall) and deeper granite/pegmatite equivalents. The granites and associated pegmatites, aplites, and Sn-Cu mineralized greisens of Cornwall and Devonshire, southwest England, are recognized as a global type of differentiated silicic magmatism and associated hydrothermal mineralization. The late-stage evolution of these granites, in particular the temporal and compositional aspects of melt-vapor equilibria, represent a critically important stage of magmatism from both scientific and economic perspectives. Among the volatile or fluxing components in the Cornish granite systems, the role of boron may be the most important and least understood. The proposed work will document the abundance and geologic associations of boron (as tourmaline) in this environment, and the tourmaline will be studied for fluid inclusions that may uniquely reveal the compositions and physical states of fluids generated in the granites and associated veins and host rocks. The results of this study will then be integrated with experimental and theoretical models developed by the principal investigator to elucidate further the geochemical cycle of boron.