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J4 ›› 2016, Vol. 22 ›› Issue (2): 308-.

• 地球物理及构造地质学 • 上一篇    下一篇

赣北景德镇韧性剪切带两类剪切指向及其构造意义

徐先兵,汤帅,林寿发   

  • 出版日期:2016-06-20 发布日期:2016-07-07

Two kinds of Shear Senses and Tectonic Implication of the Jingdezhen Ductile Shear Zone, Northern Jiangxi Province

XU Xianbing, TANG Shuai, Lin Shoufa   

  • Online:2016-06-20 Published:2016-07-07

摘要:

景德镇韧性剪切带位于新元古代江南造山带的核部,其构造变形特征和形成时代对华南新元古代至早古生代构造演
化具有重要的制约意义。景德镇韧性剪切带呈北东向展布,全长约180 km,最大出露宽度为~7 km。通过详细的野外地质
调查和室内定向薄片鉴定,在景德镇韧性剪切带中识别出了两期韧性走滑构造变形,并研究了其运动学指向和形成时的温
压条件。早期构造变形表现为左旋韧性走滑兼逆冲作用,形成温度为420~530℃,差应力为40~300 MPa;晚期变形主要表
现为右旋走滑,形成温度为300~420℃,差应力为120~350 MPa。结合前人资料,景德镇韧性剪切带左旋走滑兼逆冲作用形
成于新元古代造山作用的晚期(810~800 Ma),是由同造山挤压到后造山伸展调整的结果;而右旋走滑形成于早古生代,是
华南早古生代陆内造山作用的产物。

关键词: 运动学指向;温压条件;景德镇韧性剪切带;江南造山带;华南

Abstract:

The Jingdezhen ductile shear zone is located at the core of the Neoproterozoic Jiangnan Orogen. Structural features and
geochronology of the Jingdezhen ductile shear zone have a key implication for the Neoproterozoic to Early Paleozoic tectonic evolution of the South China Block. The Jingdezhen ductile shear zone is ~180 km long in the NE-striking orientation and ~7 km in maximum width. Two-phase ductile strike-slip shearing was identified based on detailed field investigation and observation of oriented thin sections. Moreover, the kinematic indicators and temperature-pressure conditions were studied in this paper. The early sinistral ductile strike-slip with thrusting occurred at 400~500℃ and differential stress of 40~300 MPa, whereas the dextral ductile shearing at 300~400℃ and differential stress of 120~300 MPa. Combined with the previous work, the sinistral strike-slip with thrusting of the Jingdezhen ductile shear zone took place at late stage of the Neoproterozoic orogen in the South China Block (810~800 Ma), as a result of transformation from syn-orogeny compression to post-orogeny extension. The dextral shearing of the Jingdezhen ductile shear zone occurred in the Early Paleozoic, triggered by the Early Paleozoic intracontinental orogeny of southeast China

Key words: kinematic indicator, temperature-pressure condition, Jingdezhen ductile shear zone;Neoproterozoic Jiangnan Orogen;South China Block