南海北缘早-中更新世之交新构造活动及其区域对比

NEOTECTONICS ALONG THE NORTH COAST OF SOUTH CHINA SEA AND ITS REGIONAL CORRELATION AROUND THE BOUNDARY OF THE EARLY AND MIDDLE PLEISTOCENE

文章根据一系列野外调查和年代测定以及地球化学与地球物理测试分析，阐述了南海北部早更新世湛江组和中更新世北海组的沉积相、化学组分、磁化率等特征。并描述了该区构造变形、褶皱、断裂和火山活动特点。研究结果表明，本区在0．9—0．7MaB．P．的早-中更新世转换期间（中国第三大构造-地貌阶梯主隆起期）发生了一系列构造活动．导致了沉积相由海陆交互相向陆相的转变、大陆风化和剥蚀作用的增强、海平面急剧下降、火山强烈喷发以及褶皱、断裂和不整合面的形成。这种事件群发性所指示的构造活化与中国大陆其他地区的记录相似，例如，黄土高原、青藏高原、华北、华东和西部；同时指示，青藏高原的阶段性隆升不仅导致其自身构造-地貌-气候的剧变，而且引起了周边地区乃至中国和东亚大陆环境的剧变。这种构造运动可能是在气候一构造旋回的规律下，受气候-构造耦合系统的控制，即受内外动力系统的控制，或全球构造系统和全球气候系统的控制。

Based on the age dating, geochemical and geophysical analyses, as weU as field investigation along the coast of South China Sea, the authors expatiated the characteristics of sedimentary facies, chemical components and susceptibility of the Zhanjiang Formation （ Early Pleistocene） and the Beihai Formation （ Middle Pleistocene）, and showed the pictures of deformation, folds, faults, and volcanism in the area. It is indicated that there have occurred a series of tectonic events in the northern parts of the South China Sea during the period from 0.9MaB. P. to 0. 7MaB. P. , a mainly with an increasing of conti with the formation of fold, uplifting period with sedimentary source changed from continental-oceanic to continental, nental weathering and erosion, with a dropping of sea level, with volcanic explosion, and fault and unconformity. These events indicated a tectonic activity, which is similar to the records of other areas, such as the Loess Plateau, Tibetan Plateau, West China, North China, and East China. It is also suggested that the uplifting of the Tibetan Plateau by stages not only caused great changes to its own tectonics, landform, and climate, but also effected and forced the process of environmental changes in its adjacent regions as well as Chinese continent, even the whole of East Asia. We believe that this tectonic movement was controlled by the Coupled Climato-Tectonic System and followed the rule of the Climato-Tectonic Cycle. The forcing effects of the environmental change of Chinese continent are the exogenic-endogenic geodynamic process --the global tectonic system, the global climatic system and so on.