东吴运动性质的厘定及其时空演变规律

东吴运动是华南地区二叠纪影响较大的一次地壳运动, 然而对其涵义、起始时间、构造界面位置、影响范围和运动属性等方面一直存在争议.通过对上扬子茅口组对比、不整合面特征和岩浆活动等方面的研究, 结合对华南地区二叠纪的地层、沉积及岩相古地理等综合分析, 对东吴运动的性质、地球动力学背景和时空演变规律进行了探讨.认为茅口末期峨眉山地幔柱上升引起的地壳抬升、峨眉山玄武岩的喷发和东吴运动这三者之间存在成因联系; 上扬子中晚二叠世之间的东吴运动是峨眉山地幔柱上升所造成的地壳快速差异抬升.东吴运动具有明显的时空演变规律, 空间上西强东弱、南强北弱, 时间上西早东晚、南早北晚.下扬子及华南地块可能不存在东吴运动, 其中晚二叠世的沉积作用主要受华夏古陆控制. 

Nature of the Dongwu Movement and Its Temporal and Spatial Evolution

Dongwu movement is an important geological event of the Permian in South China, however, there are still lots of disputes and controversy on the timing, dimension and nature of the Dongwu movement. This paper discusses the nature, geodynamics and evolution of the Dongwu movement. It is based on biostratigraphic correlation of the Maokou Formation and the study of an unconformity and volcanism in the Upper Yangtze block, combined with an analysis of the stratigraphy, sedimentation, lithofacies and paleogeography of the Permian in South China. This research suggests that there is a genetic relationship between the rising of the Emeishan mantle-plume, the eruption of the Emeishan basalts, and the Dongwu movement. That is, the Dongwu movement is a rapid differential crustal uplift caused by the rising of the Emeishan mantle-plume. It is stronger in the west than in the east, and it began earlier in the west. This research also shows that the Dongwu movement did not extend as far as the lower Yangtze and south Huanan block, and that the sedimentation in these areas during the Permian was controlled by the Huanan block.