High-pressure pelitic granulite containing porphyroblasts of garnet (Grt), sillimanite ( Sil), K-feldspar ( Kf) and plagioclase (PI) , and inclusions of spinel (Spl) , kyanite ( Ky) , sapphirine (Spr) and rutile (Rut) have been found from the Ailaoshan orogenic belt, southeastern Tihet, regarded as a key indicator for identification of the boundary between the Indochina and South China blocks. The temperatures and pressures calculated by garnet-biotite-plagioclase-quartz geothermobarometery and high-temperature equilibrium spinel ± quartz assemblage show the formation and evolution of the graunlite had experienced clockwise P-T path from high-pressurc/-tcmpcrature to mid-temperature and low-pressure metamorphism. That are: 1) the high-pressure/-temperature metamorphism (HP/HT) is characterized by an assemblage of Ky ± Sil ± Grt1 ± Kf1 ± PI1 ± Spr ± Ter( Kf ± PI) ± Bt1 ± Spl ± Qtz ± Ilm1 ± Rut1, and the peak P-T conditions of > 10.4kbar at 850 ~ 919℃ ; 2) the mid-temperature and low-pressure retrogressive metamorphism characterized by an assemblage of Grt2 ± Bt2 ± PI2 ± Ms ± Qtz ± Ilm, ± Rut2, and two stage P-T conditions of 4. 9 ~ 6. 5kbar at 664 -754℃ and 3. 5 -3. 9kbar at 572 -576T respectively. The dynamic metamorphic path was that the metapelitic rock experienced high-pressure/-temperature granulite-facies metamorphism in lower continental crust ( >30 km) exhumated to mid-upper crust rapidly, it might be related to the continental collision and underthrusting between the Indochina and South China blocks, and exhumation and slip shearing lately.%哀牢山构造带泥质高压麻粒岩主要由石榴石、夕线石、钾长石和斜长石变斑晶及尖晶石、铁假蓝宝石、蓝晶石、石英、金红石和钛铁矿包裹体组成,为确定印支地块和华南地块的边界提供了关键性标志.石榴石-黑云母-斜长石-石英地质温压计(GBPQ)计算结果及标志性高温矿物组合(Spl+ Qz)表明泥质高压麻粒岩的形成和演化经历了高压/高温进变质到中温/低压退变质的顺时针P-T演化过程.其中:1)高压/高温进变质阶段的矿物组合为Ky+ Sil+ Grt1+Kf1+ Pl1+Spr+ Ter( Kf+Pl) +Bt1+ Spl+ Qtz+ Ilm1+ Rut1,形成于850 ～ 919℃,≥10.4kbar;2)中温/低压退变质阶段的矿物组合为Grt2+ Bt2+ Pl2+ Ms+ Qtz+ Ilm2+Rut2,早期和晚期的温压条件分别为664～ 754℃,4.9～6.5 kbar和572 ～ 576℃,3.5 ～ 3.9kbar.反映陆壳物质在碰撞过程中俯冲到地下深处(≥30km)经高压高温变质后快速折返到中上地壳的动力学演变轨迹.
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