冈底斯新元古代-中生代沉积盆地演化

Evolution of Neoproterozoic-Mesozoic Sedimentary Basins in Gangdese Area,Tibetan Plateau

青藏高原冈底斯地处印度河-雅鲁藏布江结合带和班公湖-双湖-怒江对接带之间,其经历了复杂的沉积-岩浆演化史.将青藏高原冈底斯地层区划分为8个构造-地层分区,并分时段对各个分区的沉积特征进行归纳,总结了冈底斯从新元古代到中生代沉积盆地的发展与演化历史:冈底斯震旦纪由陆缘裂谷开始演化;晚古生代,前期以稳定宽阔的碳酸盐岩沉积为主,发育碳酸盐岩台地与台盆,从石炭纪起,开始转化为伸展性质的裂陷大陆边缘,盆地类型主要为陆缘裂谷;中生代,班公湖-怒江特提斯洋向南与雅鲁藏布新特提斯洋向北双向俯冲,大部分区域早期处于隆升状态,中生代末期发育大型的岩浆弧带,盆地类型以弧间盆地和弧前盆地为主.

The Gangdese area is located in the middle of the Tibetan Plateau.Its southern boundary is the Indus River-Brahma-putra suture zone,and northern boundary is the Bangonghu-Shuanghu-Nujiang suture zone.It is a huge tectonic-magmatic belt, nearly east-west directed.The Gangdese is divided into eight tectonic-stratigraphic subregions in this paper.The sedimentary features of eight stratigraphic subregions in different periods are generalized from Neoproterozoic to Mesozoic,and the develop-ment and evolution of the sedimentary basins in Gangdese,Tibet plateau is explored.The following three stages of evolution are revealed：（1）the Gangdese started the evolution of continental-margin rift from Sinian;（2）it mainly developed carbonate sedimentary basins in the Late Paleozoic,featuring stable and broad development of carbonate platform and interplatform ba-sins in this period.Gangdese started the development of rifted continental margin of stretch properties from Carboniferous,and the main sedimentary basins became continental-margin rift;（3）it was denuded in most areas from Early Mesozoic due to con-tinental uplift.As Bangonghu-Nujiang Tethys＇s subduction towards north and Brahmaputra＇s subduction towards south,the Gangdese developed large magmatic arc belt at last in Late Mesozoic,and the main sedimentary basins changed to retroarc ba-sin,interarc basin and forearc basin.