华南及邻区中新生代大地构造单元

MESO-CENOZOIC GEOTECTONIC ELEMENT OF SOUTH CHINA

华南大陆部分中新生代大地构造单元属南华造山带 ,可分为NW—NWW向的滨特提斯褶皱系和NE向的滨太平洋褶皱系。滨太平洋褶皱系包含东南大陆边缘弧褶皱带和东南大陆边缘弧后褶皱带 ,是晚三叠世以来多期次继承性造山运动累积叠加形成的。主要褶皱时代 ,在陆缘弧褶皱带是晚侏罗—中始新世 ;在陆缘弧后褶皱带是中晚始新世之交。讨论了华南及邻区中新生代大地构造格局及其成因和羽状对称特点 ,以及陆壳减薄板段。

It is pointed out that the Meso-Cenozoic geotectonic eoement of the continental part of South China is an orogenic belt,Nanhua orogenic belt (South Cathaysian orogenic belt).It can be subdivided into a Peri-Tethys fold system characterized by the optimized geotectonic lines taking the NW-NWW trending and a Peri-Pacific fold system dominated by the geotectonic lines of the NE trending. The Peri-Pacific fold system contains a continental marginal arc fold belt and a contnental marginal backarc fold belt of Southeast China formed by the overlap-accumulation of the polyphasic inherited orogenic since the Late Triassic.The principalage is from the Late Jurassic to the Middle Eocene in the continental marginal arc fold belt and is between the Middle and Late Eocene in the continental marginal backarc fold belt. The Youjiang fold subbelt in the Peri-Tethys fold system belongs to South China according to the custom of the Chinese geological circles. The principal age of the Late Paleozoic platform cover and the Middle-Late Triassic structural stage made up of geosynclinal type formation in the Youjiang fold subbelt is between the Middle and Late Eocene. The Meso-Cenozoic geotectonic layout of South China and adjacent regions,its origin and characteristics in feather-shaped symmetry as well as several concepts of continental crustal thinned section, active geotectonic element and passive geotectonic element are discussed.