Synorogenic movement of the Tan-Lu fault zone
Synorogenic movement of the Tan-Lu fault zone
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作者：
Zhu Guang
郯庐断裂的形成时间和模式至今仍有争议。在大别山东缘，新近发现早白垩世的郯庐左旋走滑韧性剪切带中存在早期的左旋走滑韧性剪切带。早期剪切带三个地点糜棱岩白云母样品的40 Ar/39 Ar坪年龄分别为（188.7±0.7）Ma、（189.7±0.6）Ma和（192.5±0.7）Ma。这一定年表明同造山走滑热事件。前陆沉积和构造也反映了南北板块碰撞时断裂带的活动性。断裂带内同造山构造及周边前陆沉积和构造表明，断裂带的同造山运动是一种转换断层类型，它向左错断大别山和苏鲁山约1000 km。350 km，造成了苏鲁造山带的逆时针旋转。断裂带在早白垩世活动期间，进一步向北伸展，并发生了约1000次左右的左旋位移。两百公里因此，郯庐断裂是在华北板块和华南板块碰撞作用下形成的。其同造山运动与两个板块的陆-陆碰撞过程有关。
The origin timing and the model of the Tan-Lu fault are still debatable. It was found recently on the eastern margin of Dabie Mountains that the earlier sinistral strike-slip ductile shear belts exist in the Tan-Lu sinistral strike-slip ductile shear zone of the Early Cretaceous. Muscovite samples of mylonite from three localities in the earlier shear belts yield~(40)Ar/~(39)Ar plateau ages of (188.7±0.7) Ma, (189.7±0.6) Ma and (192.5±0.7) Ma, respectively. This dating indicates a synorogenic strike-slip thermal event. The foreland sediments and structures also show the activity of the fault zone during the collision of the North and South China plates. The synorogenic structures in the fault zone as well as the peripheral foreland sediments and structures demonstrate that the synorogenic motion of the fault zone was of a transform fault type, which sinistrally offset the Dabie and Sulu orogens for ca. 350 km and caused the anti-clockwise rotation of the Sulu orogen. During the activity of the fault zone in the Early Cretaceous, it extended further north and had left-lateral displacement of ca. 200 km. Therefore, the Tan-Lu fault was derived from the collision of the North and South China plates. Its synorogenic movement was associated with the continent-continent collision process of the two plates.