周口店岩体热动力构造及定位机制研究

    THERMODYNAMIC STRUCTURES AND EMPLACEMENT MECHANISM OF THE ZHOUKOUDIAN INTRUSION

    • 摘要: 周口店岩体是一个具有两次侵入活动的复式岩株。根据与侵入体协调一致的围岩构造、岩体的流动构造、捕虏体应变测量、岩体西北缘强变形带特征及小型韧性剪切带研究,表明周口店岩体是一个典型的斜向底辟侵入、类热气球膨胀模式的岩体。岩体西北缘强变形区的“片麻状构造”是岩桨脉动形成的挤压片理(S),不是原生流动构造;岩体西北部小型韧性剪切带的剪切片理(C)晚于挤压片理(S)。它们都是岩桨脉动底辟侵入的产物。这一结论由韧性剪切带中石英组构分析得到验证。

       

      Abstract: The Zhoukoudian intrusion is a composite stock character ized by two intrusive activities. Studies of the structures of the country rocks concordant with the intrusion, flow structure of the intrusion, measurements of the strain of the xenoliths, features of the strong deformation zone on the northwestern margin of the intrusion and minor ductile shear zoaes indicate that the Zhoukoudian intrusion is a typical body resulting from oblique diapiric intrusion and with a ballooning-like model. The "gneissic structure" in the strong deformation zone on the northwestern margin of the intrusion is compression schisto sity (s) formed by magmatic pulsation rather than primary flow structure. Shear schistosity (c) in the minor ductile shear zone in the northwestern part of the intrusion was formed later than compression schistosity (s). These conclusions have been verified by the fabric analysis of quartz in the ductile shear zone.

       

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