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阿尔金南缘构造带西段新元古代—早古生代变质岩系为一套绿片岩相—低角闪岩相的中浅变质岩系,并形成绢云母-白云母带、黑云母带和石榴石-角闪石带3个递增变质带。通过对石榴石-角闪石带变质作用p-T轨迹的深入研究表明,其经历了3个阶段变质作用:即经历了俯冲碰撞深埋到30~35km深度的中高压变质作用(M1),压力可达7.27×108~9.63×108Pa;随后经历了快速抬升所导致的近等温降压变质过程(M2),压力降至4.1×108~5.62×108Pa;晚期经历了降温降压退变质作用(M3)。整个过程为顺时针方向演化的p-T轨迹,其地质动力学过程属于较典型的板块俯冲碰撞→抬升模式,表明阿尔金南缘构造带的地质构造演化经历了俯冲碰撞及碰撞后的快速抬升过程。
The Neoproterozoic-Early Paleozoic metamorphic rocks in the western margin of the Southern margin of the Arjin belt are a set of middle-shallow metamorphic rocks of the greenstone-amphibolite facies and form sericite-muscovite, biotite and garnet- Amphibole belt 3 increasing metamorphic belt. Through further study on the pT trace of metamorphism of garnet-amphibole belt, it has undergone three stages of metamorphism: that is, it undergoes the metamorphism (M1) buried deep in the depth of 30-35 km due to subduction collision, and the pressure can be Up to 7.27 × 108 ~ 9.63 × 108Pa. After that, it undergoes near-isothermal step-down metamorphism (M2) caused by rapid uplift, and the pressure drops to 4.1 × 108-5.62 × 108Pa. In late stage, . The whole process is a clockwise p-T trajectory. The geodynamic process belongs to the typical plate subduction collision → uplift mode, indicating that the tectonic evolution of the southern margin of the Arjin experienced subduction and rapid uplift after the collision.