Multiple Episodes of Fluid-Rock Interaction in Meta- Anorthosite Northwest of the Idaho Batholith

Boehls Butte斜长岩出露在爱达荷州北部岩基的宽阔边界地带，经历了多期流体-岩石相互作用，包括岩浆、区域变质和大气-热液事件。这项研究将考察流体-岩石叠加作用对斜长岩和接触处的变质岩的稳定同位素和地球化学影响。这项研究的目的是(1)区分变质后和变质后流体-岩石相互作用的同位素和地球化学效应，(2)限制火成岩的相对贡献，变质和热液作用有助于斜长岩中独特的矿物学和同位素组成的发展，以及(3)确定区域变质作用在多大程度上伴随着或仅仅被与岩基侵入有关的热液对流所叠加。流体-岩石相互作用将通过稳定同位素、流体包裹体、矿物-流体平衡和微量元素地球化学的综合研究来表征。这一结果将制约对流流体流经岩基边界带变质岩的深度、大小和时间，从而制约深部流体对流作为区域变质作用中的一种动力学过程的有效性。

The Boehls Butte anorthosite is exposed within the broad border zone of the northern Idaho batholith and has experienced multiple episodes of fluid-rock interaction, including magmatic, regional metamorphic and meteoric-hydrothermal events. This study will examine the stable isotopic and geochemical effects of superimposed fluid-rock interaction on the anorthosite and metasediments at its contact. The objectives of this study are (1) to differentiate the isotopic and geochemical effects of post-metamorphic and synmetamorphic fluid-rock interaction, (2) to constrain the relative contributions of igneous, metamorphic and hydrothermal processes to the development of unique mineralogies and isotopic compositions in the anorthosite and (3) to determine the extent to which regional metamorphism was accompanied by, or merely overprinted by, hydrothermal fluid convection associatated with batholith intrusion. Fluid-rock interaction will be characterized by a combine study of stable isotopes, fluid inclusions, mineral-fluid equilibria and trace element geochemistry. The results will constrain the depth, magnitude and timing of convective fluid flow through metamorphic rocks in the border zone of the batholith, constraining the efficacy of deep-seated fluid convection as a dynamic process in regional metamorphism.