Origin and tectonic significance of a Mesozoic multi-layer over-thrust system within the Yangtze Block (South China)
Origin and tectonic significance of a Mesozoic multi-layer over-thrust system within the Yangtze Block (South China)
复制标题
DOI：
10.1016/s0040-1951(02)00646-7
复制
发表时间：
2003-01
期刊：
影响因子：
2.9
通讯作者：
D. Yan;Mei‐Fu Zhou;Honglin Song;Xin-Wen Wang;J. Malpas
中科院分区：
文献类型：
--
作者：
D. Yan;Mei‐Fu Zhou;Honglin Song;Xin-Wen Wang;J. Malpas
在扬子地块（华南），发育发育的中生代逆冲系统，从东南部的雪峰山、武陵山延伸至西北的四川盆地。该系统由薄皮和厚皮逆冲单元组成，由边界滑脱断层（大阴断层）分隔开。在西北方向，薄皮带的特点是西北方向有人字形背斜和箱形向斜，或者东南方向有人字形向斜。前一种结构样式显示背斜核心暴露较窄，向斜核心暴露较宽。逆冲拆离沿着志留系（Fs）和下寒武统（Fc）地层发生，主要与背斜相关。向东南方向，这种变形类型逐渐转变为以人字形向斜为特征的变形类型，并伴有沿志留系（Fs）、寒武系（Fc）和下震旦统（Fz）地层的主要拆离断层。然而，还有许多次要的反向推力。因此，薄皮带就像北美阿普拉契山脉的谷岭省。厚皮带在结构上覆盖薄皮带，其特点是存在包括雪峰和武陵推覆体在内的大量雪峰。因此，它可以与阿巴拉契亚的蓝岭省相媲美。华南这一逆冲系统的构造模式可以用一个模型来解释，该模型涉及不同演化阶段沿不同地层的滑脱断层作用。该系统是通过西北逐步变形过程发展起来的，最早的分层是沿着下震旦统地层（Fz）进行的。对平衡地质剖面的分析显示，薄皮单元缩短了约 18.1-21%（总共 88 公里），而厚皮单元则至少缩短了这个量。晚侏罗世至白垩纪期间，自东南向西北的挤压变形发生在扬子地块与华北地块向西渐进碰撞之后，表明造山事件本质上是陆内造山事件。
In the Yangtze Block (South China), a well-developed Mesozoic thrust system extends through the Xuefeng and Wuling mountains in the southeast to the Sichuan basin in the northwest. The system comprises both thin- and thick-skinned thrust units separated by a boundary detachment fault, the Dayin fault. To the northwest, the thin-skinned belt is characterized by either chevron anticlines and box synclines to the northwest or chevron synclines to the southeast. The former structural style displays narrow exposures for the cores of anticlines and wider exposures for the cores of synclines. Thrust detachments occur along Silurian (Fs) and Lower Cambrian (Fc) strata and are dominantly associated with the anticlines. To the southeast, this style of deformation passes gradually into one characterized by chevron synclines with associated principal detachment faults along Silurian (Fs), Cambrian (Fc) and Lower Sinian (Fz) strata. There are, however, numerous secondary back thrusts. Therefore, the thin-skinned belt is like the Valley and Ridge Province of the North American Applachian Mountains. The thick-skinned belt structurally overlies the thin-skinned belt and is characterized by a number of klippen including the Xuefeng and Wuling nappes. It is thus comparable to the Blue Ridge Province of Appalachia. The structural pattern of this thrust system in South China can be explained by a model involving detachment faulting along various stratigraphic layers at different stages of its evolution. The system was developed through a northwest stepwise progression of deformation with the earliest delamination along Lower Sinian strata (Fz). Analyses of balanced geological cross-sections yield about 18.1–21% (total 88 km) shortening for the thin-skinned unit and at least this amount of shortening for the thick-skinned unit. The compressional deformation from southeast to northwest during Late Jurassic to Cretaceous time occurred after the westward progressive collision of the Yangtze Block with the North China Block and suggests that the orogenic event was intracontinental in nature.