Accretionary-collisional events occurred at the western margin of the Tuva-Mongolian microcontinent are used to explain the largely contradictory Cambrian geodynamic history of the western Central Asian Orogenic Belt (CAOB).

This study presents new data for the Erzin metamorphic complex in order to constrain the petrogenesis and tectonic implications of the metamorphic rocks in this complex. The Erzin complex in the tectonic Erzin zone is composed of high-grade metamorphic rocks that have formed under variable metamorphic conditions (T = 730–835 °C, P = 5.3–7.5 kbar). In the Erzin complex, metamorphic rocks have undergone multiple stages of ductile deformation with subvertical mineral lineation and were then superimposed by sub-horizontal ductile deformation. The stages of tectonic deformation are close in time and mark collisional stages characterized by a sequential change from the compression regime to the extension regime in the period of 495 ± 5 Ma. The determination of the time interval is based on structural and petrological data, previously published materials, as well as the dating of granite dikes (U-Pb, zircon) sealing the Erzin complex. P-T conditions and structural-petrological studies analysed in this paper suggest that the formation of the Erzin metamorphic complex occurred as a result of a collisional event between the Tannuola island arc and Tuva-Mongolian microcontinent. We suggest that the Erzin metamorphic complex is important for study of transitional regime between the collisional event and initial orogenic collapse in the ancient fold belts. Metamorphic record of the Tuva-Mongolian microcontinent provides important information about the processes that occurred at the Early Paleozoic geodynamic evolution in the western CAOB.

图瓦-蒙古微大陆西缘发生的增生碰撞事件被用来解释中亚造山带西部（CAOB）的寒武纪地球动力学历史大相径庭。

这项研究提供了 Erzin 变质杂岩的新数据，以限制该杂岩中变质岩的岩石成因和构造意义。Erzin 构造带的 Erzin 杂岩由在可变变质条件（T = 730-835 °C，P = 5.3-7.5 kbar）下形成的高级变质岩组成。尔津杂岩体中，变质岩经历多期韧性变形，具有近垂直矿物线理，然后叠加亚水平韧性变形。构造变形阶段在时间上接近，标志着碰撞阶段，其特征是在 495±5 Ma 期间从压缩状态到伸展状态的顺序变化。时间间隔的确定基于结构和岩石学数据、以前发表的材料、以及密封 Erzin 复合体的花岗岩脉络（U-Pb、锆石）的年代测定。本文分析的 PT 条件和构造-岩石学研究表明，Erzin 变质杂岩的形成是 Tannuola 岛弧与图瓦-蒙古微大陆之间碰撞事件的结果。我们认为 Erzin 变质杂岩对于研究古代褶皱带中碰撞事件和初始造山崩塌之间的过渡机制具有重要意义。图瓦-蒙古微大陆的变质记录提供了关于中亚盆地西部早古生代地球动力学演化过程的重要信息。本文分析的 PT 条件和构造-岩石学研究表明，Erzin 变质杂岩的形成是 Tannuola 岛弧与图瓦-蒙古微大陆之间碰撞事件的结果。我们认为 Erzin 变质杂岩对于研究古代褶皱带中碰撞事件和初始造山崩塌之间的过渡机制具有重要意义。图瓦-蒙古微大陆的变质记录提供了关于中亚盆地西部早古生代地球动力学演化过程的重要信息。本文分析的 PT 条件和构造-岩石学研究表明，Erzin 变质杂岩的形成是 Tannuola 岛弧与图瓦-蒙古微大陆之间碰撞事件的结果。我们认为 Erzin 变质杂岩对于研究古代褶皱带中碰撞事件和初始造山崩塌之间的过渡机制具有重要意义。图瓦-蒙古微大陆的变质记录提供了关于中亚盆地西部早古生代地球动力学演化过程的重要信息。我们认为 Erzin 变质杂岩对于研究古代褶皱带中碰撞事件与初始造山崩塌之间的过渡机制具有重要意义。图瓦-蒙古微大陆的变质记录提供了关于中亚盆地西部早古生代地球动力学演化过程的重要信息。我们认为 Erzin 变质杂岩对于研究古代褶皱带中碰撞事件和初始造山崩塌之间的过渡机制具有重要意义。图瓦-蒙古微大陆的变质记录提供了关于中亚盆地西部早古生代地球动力学演化过程的重要信息。