陶湾岩块碳酸质糜棱岩变质变形特征及形成环境研究

发布时间：2018-03-26 04:47

  本文选题：陶湾岩块　切入点：碳酸质糜棱岩　出处：《合肥工业大学》2015年硕士论文

【摘要】：东秦岭造山带北缘的陶湾岩块中分布着一套碳酸质糜棱岩,具明显的塑性变形,其展布和变质变形特征严格受洛南—栾川断裂带的控制和影响。根据洛栾—栾川断裂带晚加里东-早海西期强烈活动的特点,认为是陶湾岩块碳酸盐岩在洛南—栾川断裂带晚加里东—早海西期构造活动过程中形成的。因此,对这套碳酸质糜棱岩的变质变形特征及形成环境分析,可揭示洛南—栾川断裂带在这一时期构造活动的运动学、动力学及流变学特征。本文通过野外详细的观察和测量,结合室内显微构造分析和温压条件的计算,确定陶湾岩块碳酸质糜棱岩面理产状基本倾向NNE,线理发育,表现为由N向S逆冲兼有左旋剪切的运动学特征；其变质相属低绿片岩相,变形机制是以方解石动态重结晶和细粒化作用为主的塑性变形；变形温度为350℃-470℃,差异应力为10-40MPa；石英应变椭球体形态为压扁型椭球体,显示陶湾岩群遭受了强烈挤压变形。所以,陶湾岩群碳酸质糜棱岩是在强烈的斜向挤压碰撞环境下形成的,是秦岭微陆块向华北板块下斜向俯冲碰撞的结果。
[Abstract]:In the northern margin of the East Qinling orogenic belt, there is a set of carbonate mylonites in the Taowan block, with obvious plastic deformation. The distribution and metamorphic deformation characteristics are strictly controlled and influenced by the Luonan-Luanchuan fault zone. According to the strong activity in the late Caledonian and early Hercynian period in the Luoluan-Luanchuan fault zone, It is considered that carbonate rocks in the Taowan block were formed during the late Caledonian to early Hercynian tectonic activity in the Luonan-Luanchuan fault zone. Therefore, the metamorphic deformation characteristics and forming environment of the carbonate mylonite are analyzed. The characteristics of kinematics, dynamics and rheology of tectonic activity in Luonan-Luanchuan fault zone during this period can be revealed. Through detailed observation and measurement in the field, combined with indoor microstructural analysis and calculation of temperature and pressure conditions, It is determined that the metamorphic facies of the carbonate mylonites in the Taowan block are characterized by low greenschist facies, with the basic tendency of NNEs and the linear development, which is characterized by the kinematic characteristics of left-lateral shear from N to S thrusts, and the metamorphic facies is a low-greenschist facies. The deformation mechanism is plastic deformation with calcite dynamic recrystallization and fine granulation, the deformation temperature is 350 鈩，

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