基于变斑晶生长定量数据的造山带P-T-t-D研究:以祁连托勒牧场为例

变斑晶面理弯切轴测量技术结合电子探针微区成分分析和THERMOCALC视剖面图温压计算方法，建立P-T-t-D轨迹，是造山过程重建研究的重要突破。本项目拟选取北祁连托勒牧场典型多期生长石榴子石变斑晶为研究对象，在野外典型剖面调查、宏观变形分析和室内岩相学研究基础上，测定面理弯切轴，确定各期变形应力方向，计算各期变质作用P-T并测定变斑晶不同环带部位原位独居石电子探针U-Th-Pb年龄，并尝试：1）运用阴极发光（CL）图像划分石榴子石多期生长期次，建立期次划分图像特征识别标准；2）运用EBSD测定多期生长石榴子石变斑晶不同部位所包含石英的晶格优选方向（LPO），查明LPO作为剪切方向判定标志及变形过程划分依据的适用范围和影响因素。以期为P-T-t-D轨迹研究提供更为快捷、准确的定量数据支持，促进造山运动变质变形演化过程重建由定性，半定量向定量化跨越。

The measurement of foliation inflection/intersection axes (FIA) preserved within porphyroblasts, have revealed much more extensive histories of deformation and metamorphism than previously recognized during the study of orogenesis. FIA combined with electron microprobe analysis and THERMOCALC pseudosection P-T calculation method to establishment P-T-t-D path is an important breakthrough for the reconstruction of the orogenesis process. This project aims to select the Qilian Tuolemuchang typical multi stage growth garnet porphyroblasts as the research object, using field investigation, petrography study, macroscopic deformation and microstructure analysis, determine the horizontal bulk shortening direction. Calculate the P-T and obtain the U-Th-Pb age of in-situ monazite in different zone of multi stage growth garnet porphyroblasts .And then trying to 1) using cathodoluminescence (CL) image to divide garnet growth stages, establish the stage division of image feature recognition criteria; 2) Investigating the relationship between the quartz LPO and buck shortening direction, to provide more quantitative data for P-T-t-D path reconstruction.Promote orogenesis metamorphism and deformation evolution process reconstruction from qualitative, semi quantitative to quantitative.