元古代华南洋的轮廓

The outline of the Proterozoic South China Ocean

地质界追寻华南洋的研究已有40年历史,在已有研究基础上,通过《中国区域地质志·江西志》《中国矿产地质志·江西卷》及《华南洋-滨太平洋构造演化与成矿》专题对中新元古代华南洋的地质特征与相关地质构造及成矿问题有了进一步的认识:凭祥-歙县-苏州结合带与金沙江-红河结合带在河内市北面相连,为中新元古代华南洋的消亡潜没地带,构成了扬子板块与新厘定的华夏-东南亚板块分界(简称金沙江-红河-歙县-苏州结合带),现今是一条向南弯曲的纬向构造带;华南洋是扬子古板块与华夏-东南亚古板块间的中新元古代大洋,约闭合于820±Ma,板块碰撞发生了晋宁运动,扬子陆块与华夏-东南亚陆块基本固结,并连为一体;该区印支期以来为欧亚板块重要组成部分,新元古代晚期815±Ma至早古生代形成华南裂谷系,晚古生代以来先后受特提斯构造域、古太平洋构造域复合形成了中国南部及邻区高原、大陆、海域、岛弧的地质构造格局;在华南洋潜没地带的基础上经不断发展演化形成了以S、I型两大岩浆成矿系列为特色的钨锡铜金多金属贵稀金属“金沙江-红河-钦州湾-杭州湾”巨型成矿带。

The geological circle has been studying the South China Ocean for 40 years. Based on the existing studies, the geological features of the middle Neogene South China Ocean and related geological structures and mineralization issues have been further understood through the topics of Regional Geology of China: Jiangxi, Mineral Geology of China:Jiangxi, and Evolution and Mineralization in South China Ocean –Marginal Pacific. The Pingxiang –Shexian –Suzhou junction zone connects the Jinsha River–Red River junction zone to the north of Henei, which is the subduction zone of the South China Ocean in the middle Neogene. It formed the boundary between the Yangtse plate and the newly-defined China-Southeast Asia plate(referred to as the Jinsha River–Red River–Shexian–Suzhou junction zone), which is now a latitudinal tectonic belt bending southward. The South China Ocean is a Meso-Neoproterozoic ocean between the Yangzi Paleo-plate and the Cathaysia-Southeast Asia Paleo-plate, closed at about 820± Ma. The Jinning movement took place during the collision of the plates, resulting in a consolidation of the Yangtze Block and the Cathaysia-Southeast Asia Block,where they united into one. The region has been an essential part of the Eurasian plate since the Indo-Chinese period, and the South China Rift System had been formed from 815± Ma in the late Neogene to the early Paleozoic. The Tethys and Paleo-Pacific tectonic domains have formed the geological tectonic framework of southern China and plateaus, continents,seas, and island arcs of the neighboring areas since the late Paleozoic. The subduction zone of the South China Ocean has evolved into the “Jinsha River–Hong River–Qinzhou Bay–-Hangzhou Bay” mega metallogenic belt of tungsten-tin-coppergold polymetallic precious and rare metals, featuring two major magmatic mineralization series of S and I types.