中文摘要：

点苍山-哀牢山变质杂岩带中北段嘎洒地区出露了多种典型的变沉积岩，其中夕线石榴黑云二长片麻岩和二云母片岩保存多期/多阶段矿物相转变特征，本文通过岩相学和矿物化学的综合分析，并结合传统矿物对温压计的估算结果，限定上述典型变沉积岩峰期角闪-麻粒岩相（M1）阶段、近等温减压-高温剪切变形阶段（M2）和晚期退变质（M3）阶段的矿物组合及变质温压条件。峰期角闪-麻粒岩相（M1）阶段的矿物组合为：石榴石（Grt）＋板柱状夕线石（Sil1）＋黑云母（Bt1）＋钾长石（Kfs）＋斜长石（Pl）＋石英（Qtz）＋钛铁矿（Ilm），变质温度压力条件为t=690～750℃，p=690～810 MPa；近等温减压-高温剪切变形阶段（M2）阶段，稳定矿物组合为：Grt＋Sil2＋Bt2＋Kfs＋Pl＋Qtz＋Ilm，黑云母在强烈走滑剪切作用下发生脱水熔融反应：2 Bt→Sil＋6（Mg，Fe）O＋K2O＋5 Qtz＋2 H2O，石榴石、黑云母和夕线石等受到剪切变形影响而发生强烈定向，形成的温度压力条件为t=650～720℃，p=450～630 MPa；晚期退变质阶段（M3）的稳定矿物组合为：Qtz＋Bt＋Ms＋Pl，退变的温度压力条件为t=580～640℃，p=400～500 MPa。其变质演化p-T轨迹样式具有近等温减压的顺时针型式，表明点苍山-哀牢山变质杂岩带曾经历了一次明显的俯冲-碰撞造山事件，峰期变质可达到角闪-麻粒岩相；在碰撞后的构造折返过程中，上述变质岩石发生强烈的高温剪切变形作用，并伴随着黑云母等含水矿物的脱水熔融。

英文摘要：

Meta_sedimentary rocks comprising sillimanite_garnet_biotite gneisses and mica schist are cropped out in the middle_north segment of Ailao Mountain me tamorphic complex belt. Petrographic observation reveals that the sillimanite_ga rnet_biotite gneisses experienced amphibolite_granulite facies metamorphism and subsequent retrogressive superimposition. Traditional thermobarometry （GB_GASP） was applied to constraining pT conditions of the mineral assemblage at each metamorphic stage. The mineral assemblage of the peak stage （M1） is character ized by Grt＋Sil1＋Bt1＋Kfs＋Pl＋Qtz＋Ilm, recording pT conditions of 690~7 50℃ and 690~810 MPa. The near_isothermal decompressional stage （M2） is disti nguished by the directional alignment of all metamorphic minerals, with typical dehydration reaction being 2 Bt→Sil＋6 （Mg, Fe）O＋K2O＋5 Qtz＋2 H2O, and minera l assemblage is characterized by Grt＋Sil2＋Bt2＋Kfs＋Pl＋Qtz＋Ilm, formed un der pT conditions of 650~720℃ and 450~630 MPa. The mineral assemblage of the retrograde stage （M3） is composed of Bt＋Ms＋Qtz＋Pl, suggesting pT con ditions of 580~640℃ and 400~500 MPa. The metamorphic evolution is characteriz ed by an isothermal decompressional clockwise pT path, revealing a subducti on and continent_continent collision process between Indian and Yangtze blocks, following a tectonic exhumation accompanied by high temperature strike_slip shea ring and biotite dehydration-melting.