Strike-Slip tectonics along the Tan-Lu fault system, East Asia

潭庐断裂系是东亚地区最大的走滑断裂。自1995年以来，我们从山东到广东一直在调查这一问题。(1)通过对华南地块下、上白垩统地层(红砂岩和粉砂岩)的古地磁分析，得到的VGP结果表明，潭庐断裂系的浙中地区与华南地块其他地区存在逆时针旋转。早白垩世的VGP平均位置比晚白垩世的VGP位置变化更大。(2)潭庐断裂带存在以左旋走滑为主的左旋走滑运动，即左旋梯状褶皱、不对称的次要构造和近水平的条带。(3)山东潭鲁断裂带的断裂岩主要由断裂角砾岩和碎裂岩组成，不含糜棱岩。第三系玄武岩与断裂岩复盖，但不被潭庐断裂带主干断裂F_3切割。(4)马站盆地早白垩世(82 Ma)锆石年龄的沉积中心与主断裂走向平行迁移。综合上述特征，认为潭庐断裂系在晚白垩世为水平运动，走滑运动在其主断裂的释放弯处形成拉分盆地。

The Tancheng-Lujiang (Tan-Lu) fault system is the biggest strike-slip fault in East Asia. We have been investigating it from Shandong to Guangdong since 1995. The following results were obtained : (1) The resultant VGPs suggest that the central Zhejian along the Tan-Lu fault system has a counterclockwise rotation against the other regions in the Huanan block, based on paleomagnetic analysis of the Lower to Upper Cretaceous strata (red sandstones and siltstones). The mean VGP position of the Early Cretaceous is more variable than that of the Late Cretaceous. (2) There is evidence for a predominant left-lateral strike-slip movement along the Tan-Lu fault zone ; i.e., left-hand en echelon folds, asymmetrical minor structures and almost-horizontal striations. (3) The fault rock of the Tan-Lu fault zone in Shandong Province is composed mainly of fault breccia and cataclasite, but not mylonite. The Tertiary basalt covers with the fault rock, but is not cut by the main fault F_3 of the Tan-Lu fault zone. And (4) The depocenter of the Early Cretaceous (82Ma FT zircon age) Mazhan basin migrates parallel to the strike of the main fault. Judging from the above-noted features, it is concluded that the Tan-Lu fault system moved horizontally during the Late Cretaceous, and the pull-apart basin was formed at the releasing bend along its main fault due to the strike-slip movement.