【摘要】 利用南海北部琼东南盆地的高精度2D和3D地震资料,对盆地不同区域里的陆坡到深水盆地的块体流沉积特征进行了研究。结果发现,琼东南盆地东部和西部陆坡体系发育的块体流沉积表现出不同的特征:盆地东部陆坡体系下块体流沉积头部以变形程度较小的滑移体的广泛发育为特征,整体规模较小;盆地西部块体流沉积头部以变形强烈的杂乱反射为特征,侵蚀作用强烈,规模较大,同时在其趾部变形强烈的地层中发育有一系列平行、亚平行的逆冲断层。琼东南盆地东西部块体流沉积特征差异性产生的原因有:1)盆地东西部陆坡沉积格架不同,西部的陡倾陆坡比东部的宽缓陆坡更加有利于块体流沉积的发育;2)盆地地貌特征对块体流沉积发育的制约,琼东南盆地南部隆起对块体流沉积起到遮挡的作用,阻止了西部块体流的运动。陆架边缘断层活化相关的地震活动是块体流沉积的一个重要触发机制。更多还原

【Abstract】 Based on high-resolution 2D and 3D seismic data in Qiongdongnan basin,in northern South China Sea,the characteristics of mass turbidity depositions(MTDs) in different parts of the basin,from the slope system to abyssal plain,have been studied.The result shows that the characteristics of MTDs are different from the eastern to western part in Qiongdongnan basin.In eastern part,the head of MTDs is characterized by the slides,with little or no deformation,and the MTDs are of small scale.While in the western part,chaotic seismic facies and intense erosion are the main features of the head of MTDs,and the MTDs are of large scale,meanwhile,there is a series of parallel or sub-parallel thrusts in the strongly deformed strata in the toe of MTDs.There are mainly two reasons for the differences.Firstly,comparing to the eastern part,the western part of the basin has steeper slope gradient,which is favourable for the development of MTDs.The second lies in the morphology of the basin.The southern high stops the MTDs transporting along the slope.According to the relationship between the head of MTDs and the faults along the shelf margin,the earthquake related to reactivity of the faults is one of the triggers for the development of MTDs.更多还原