中国东海北北东向和北西向断裂带研究的新认识

对东海重、磁资料进行了各种转换处理,结合地震、地质资料,综合定性和定量解释的成果,对中国东海北北东向陆架西缘断裂带、陆架东缘断裂带和北西向桃花-粟国断裂带、渔山-久米断裂带进行了研究。指出中国东海北北东向和北西向断裂带中生代以来的活动经历了三个阶段,即印支-早燕山阶段的北北东向断裂带左旋平移、北西向断裂带碰撞、挤压,晚燕山-早喜山阶段北北东向断裂以“犁式正断层”方式活动,北西向断裂带左旋平移活动和晚喜山阶段北西向断裂的左旋平移活动。断裂活动表现出自西北向东南逐渐变新的特点。由于两组断裂带的活动。造成了东海盆地“东西分带”、“南北分块”的基本构造格局。三个阶段的活动方式分别与特提斯洋的俯冲、太平洋-库拉板块的北移,特提斯洋的封闭、印度板块的向北移动及太平洋板块运动方向的转变有关。

On Evolution of the NNE and NW Tranding Faults in the East China Sea

Through qualitative and quantitative interpretation of gravity and magneticanomalies, along with reflection, refraction seismic and geological information, theevolution history of the NNE trending continental shelf fault, western continentalshelf fault and the NW trending Taohua-Shuguo fault as well as Yusan-Kumi faultin East China Sea since mesozoic is disscussed. The evolution of these faults since mesozoic may be divided into three stages.That is the sinistral transcurrent movement of the NNE trending faults and thecompressive movement of the NW trending faults during Indo-Chinese Epoch andearly Yanshanian Epoch; the tensile movement of the NNE trending faults and thesinistral transcurrent movement of the NW trending faults duing late YanshanianEpoch and early Himalayanian Epoch; the ceasing of movement of NNE trendingfaults and the sinistral transcurrent movement of the NW trending faults duringlate Himalayanian Epoch. It seems that the movement was gradually transformedfrom northwest to southeast. Because of the movement of the two trending fault groups, the tectonic frame-work of the East China Sea was formed, which may be divided into five geologicalzones from west to east and two blocks from north to south. The differentmovement forms of the two trending fault groups since Mesozoic were related tothe subduction of Tethys and northward movement of Pacific-Kula plate, thedisappearence of Tethys sea and northward movement of Indian plate, the movementdirection change of Pacific plate together with the collision of Indian plate withEurasian continent, respectively.