Granulite and Eclogite Facies Metamorphism of the Carolina Arc Terrane: Implications for Pre-Alleghanian Collision Tectonics in the Southern Appalachians

9805159 Dennis本项目详细研究了南卡罗来纳州中部皮埃蒙特榴辉岩和相关高品位岩石的分布、起源和P-T-t历史，将阐明前Alleghanian碰撞在卡罗莱纳造山带演化中的作用，并为其他碰撞造山带中高压岩石的形成和折返提供见解。我们对这些榴辉岩及其周围片麻岩的研究工作将包括：（1）详细填图（1：24，000），以确定榴辉岩相岩石及其周围片麻岩在选定的四边形中的分布;（2）根据原生矿物相的化学分带、退变矿物成分和石榴石中的矿物包裹体计算古P-T-t轨迹;在包裹体套中寻找可能的超高P矿物组合。计算围生片麻岩的古P-T-t轨迹，寻找围生片麻岩中残留的高磷组合。(3)利用全岩常量和微量元素地球化学方法，结合榴辉岩及其周围片麻岩的分布和时代关系，确定了榴辉岩及其周围片麻岩的原岩。

9805159DennisThis project is a detailed study of the distribution, origin, and P-T-t history of eclogites and associated high grade rocks in the central Piedmont of South Carolina that will illuminate the role of pre-Alleghanian collisions in the evolution of the Carolina terrane, and provide insights into the formation and exhumation of high pressure rocks in other collisional orogens. Our work on these eclogites and their enclosing gneisses will include: (1) Detailed mapping (1:24,000) to determine the distribution of eclogite facies rocks and their enclosing gneisses in selected quadrangles; (2) Calculation of paleo P-T-t paths based on chemical zonations in the primary mineral phases, retrograde mineral compositions, and on mineral inclusions in garnet; search for possible ultra-high P mineral assemblages in the inclusion suites. Calculation of paleo P-T-t paths for the enclosing gneisses, and search for relict high P assemblages in the enclosing gneisses. (3) Determination the protoliths of the eclogites and their enclosing gneisses by whole rock major and trace element geochemistry, combined with their distribution and age relationships.