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新疆阿勒泰地区发育了红柱石-矽线石型递增变质带,由绿泥石-黑云母带、黑云母-石榴石带、石榴石-十字石带、十字石-红柱石带和矽线石带组成,根据石榴石成分环带、变质与变形关系、矿物共生组合演化等特征,将变质作用分为峰前期、峰期和峰后期3个演化阶段。峰前期、峰期为连续的递增变质过程,形成典型的中-低压过渡型递增变质带,峰后期属于退变质过程。据石榴石-斜长石-黑云母-白云母-石英组合内部一致地质温压计估算出峰期温度-压力:T=580℃～670℃,P=0.4GPa～0.5GPa。变质作用演化具有顺时针的PTt轨迹,代表陆壳有一定程度的构造增厚,但幅度不大,没有大规模的陆壳俯冲或拆沉作用,这种增厚可能以陆壳的构造叠置机制为主。总体相当于地体间斜向走滑兼有一定垂直分量的拼合过程的地球动力学机制。
In the region of Altay, Xinjiang, the evergreen-stilbite metamorphic belt developed from chlorite-biotite belt, biotite-garnet belt, garnet-spar, barite-andalusite and sillimanite According to the characteristics of the garnet composition belt, metamorphism and deformation, and the evolution of mineral assemblages, metamorphism can be divided into three stages: pre-peak, peak and post-peak phases. The pre-peak and peak periods are continuous ascending metamorphic processes, forming a typical medium-low pressure transitional progressive metamorphic belt, which belongs to retrogressive metamorphism during the later period of the peak. The temperature and pressure at peak temperature were estimated from the consistent geothermometer in the garnet - plagioclase - biotite - muscovite - quartz assemblage. T = 580 ℃ ~ 670 ℃, P = 0.4GPa ~ 0.5GPa. The evolution of metamorphism has a clockwise PTt trajectory, representing a certain degree of tectonic thickening of the continental crust, but not in large amplitude. There is no massive subduction or decollement of the continental crust, The main mechanism. Overall, it is equivalent to the geodynamics mechanism of the jointing process that the oblique strike-slip and the vertical component have a certain vertical component.