Syn-collisional transform faulting of the Tan-Lu fault zone, East China
Syn-collisional transform faulting of the Tan-Lu fault zone, East China
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DOI：
10.1007/s00531-007-0225-8
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发表时间：
2009-02
影响因子：
2.3
通讯作者：
Guang Zhu;Guosheng Liu;Manlan Niu;C. Xie;Yong Sheng Wang;Biwei Xiang
中科院分区：
文献类型：
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作者：
Guang Zhu;Guosheng Liu;Manlan Niu;C. Xie;Yong Sheng Wang;Biwei Xiang
关于中国东部大陆规模的潭庐断裂带的成因，目前仍存在争议。大别造山带(道布)和苏鲁造山带(SOB)沿NE-NNE-TLFZ方向左偏约550公里。在TLFZ中发现了同碰撞、左旋韧性剪切带。用~(40)Ar/~(39)Ar法测定了13个从糜棱岩中分离出来的多硅白云母的年龄。给出了道布东缘剪切带的冷却年龄为198~181 Ma，而SOB西缘剪切带的冷却年龄为221~210 Ma。前陆盆地沉积的分布特征表明，上三叠统地层沉积之前，TLFZ发生了道布和SOB的左旋错动。道布和SOB周围的边缘构造支持同碰撞断裂，并指示了道布在位移过程中的逆时针旋转。与潭庐断裂同时代的与地壳俯冲作用有关的褶皱和逆冲断裂作用比与造山折返作用有关的前陆盆地沉积更古老。多条证据表明，TLFZ发育于晚三叠世末期，道布与SOB经历了南中国地块的地壳俯冲，是一条同碰撞转换断裂。认为地壳俯冲速率的东移是造成左旋转换断裂的原因。
Origin of the continental-scale Tan-Lu fault zone (TLFZ), East China, remains controversial. About 550 km sinistral offset of the Dabie orogenic belt (DOB) and Sulu orogenic belt (SOB) is shown along the NE-NNE-striking TLFZ. Syn-collisional, sinistral ductile shear belts in the TLFZ have been identified. Thirteen phengite bulk separates from the mylonites were dated by the40Ar/39Ar method. They gave cooling ages of the 198–181 Ma for the shear belts along the eastern margin of the DOB and 221–210 Ma from the western margin of the SOB. Distribution of the foreland basin deposits suggests that sinistral offset of the DOB and SOB by the TLFZ took place prior to deposition of the Upper Triassic strata. The marginal structures around the DOB and SOB support syn-collisional faulting, and indicate anticlockwise rotation of the DOB during the displacement. The folding and thrust faulting related to crustal subduction, coeval with the Tan-Lu faulting, is older than the foreland basin deposition related to the orogenic exhumation. Several lines of evidence demonstrate that the TLFZ was developed as a syn-collisional transform fault during latest Middle to earliest Late Triassic time when the DOB and SOB experienced crustal subduction of the South China Block (SCB). Eastward increase of the crustal subduction rates is believed to be responsible for the sinistral transform faulting.