Structural and geochronological constraints on the Mesozoic‐Cenozoic tectonic evolution of the Longmen Shan thrust belt, eastern Tibetan Plateau
Structural and geochronological constraints on the Mesozoic‐Cenozoic tectonic evolution of the Longmen Shan thrust belt, eastern Tibetan Plateau
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DOI：
10.1029/2011tc002867
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发表时间：
2011-12
期刊：
影响因子：
4.2
通讯作者：
D. Yan;Mei‐Fu Zhou;Shubo Li;Guo-Qin Wei
中科院分区：
文献类型：
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作者：
D. Yan;Mei‐Fu Zhou;Shubo Li;Guo-Qin Wei
龙门山冲断带经历了与晚三叠世南北陆块碰撞有关的D1变形，随后又经历了与青藏高原向东生长有关的D2和D3变形。D1以中等紧密褶皱（f1）、间隔劈理（S1）、矿物线理（L1）、多级再活化断层和顶向南逆冲断层为标志。这一变形开始于237 Ma之前，结束于208 Ma。193-159 Ma的D2变形是自上而下的东南方向和正常的韧性性质，并与半地堑盆地的形成有关。龙门山造山带中生代的变形与古特提斯洋体岩石圈的俯冲作用有关，随后华南地块俯冲到松潘-甘孜地体之下。D1产于上覆的松潘-甘孜板块的近侧，最有可能是由后退的华南地块上方的板角流驱动的。D2型伸展型松潘-甘孜浊积岩盆地是由后退俯冲带之上的逆冲板块的回滚和迁移作用形成的。从D1到D2的变形模型类似于地中海式模型。晚白垩世至今，D3以SE向逆冲推覆作用为特征，伴随着快速剥蚀和右旋走滑断层的逐步迁移。因此，龙门山冲断带经历了中生代的挤压和伸展作用，并叠加了晚白垩世至新生代的挤压作用。
The Longmen Shan thrust belt in the eastern margin of the Tibetan Plateau underwent deformation of D1 associated with the Late Triassic collision between the North and South China Blocks, followed by deformation of D2 and D3 related to the eastward growth of the Tibetan Plateau. The D1 is marked by moderately tight folds (f1), spaced cleavage (S1), mineral lineation (L1), multistage reactivated faults, and top‐to‐the south thrusting. This deformation initiated before 237 Ma and ended at 208 Ma. The 193–159 Ma D2 deformation is top‐to‐the‐southeast directed and normal ductile in nature and was associated with the formation of half‐graben basins. The Mesozoic deformation of the Longmen Shan belt was related to the subduction of the Paleo‐Tethys oceanic lithosphere, followed by the South China Block underneath the Songpan‐Ganze Terrane. The D1 was produced in the pro‐side of the overriding Songpan‐Ganze plate, most probably driven by slab corner flow above the retreating South China Block. The D2 and extensional Songpan‐Ganze turbidite basin were produced by roll‐back and migration of the overriding plate above the retreating subduction zone. This model for the deformation from D1 to D2 is similar to a Mediterranean‐style model. The D3 is characterized by SE‐ward thrusting with stepwise migration of rapid denudation and dextral strike‐slip faulting during the Late Cretaceous to present. Therefore, the Longmen Shan thrust belt involved Mesozoic compressional and extensional events that were overprinted by the Late Cretaceous to Cenozoic compressional event.