西藏甲马弧内盆地的形成演化

The formation and evolution of the Jiama intra-arc basin in Xizang

位于西藏冈底斯带的甲马弧内盆地是随着甲马岛弧的发育而产生的 ,沉积了一套滨浅海相活动大陆边缘的沉积物 ,主要由碎屑岩与海绵礁灰岩构成。在盆地内的上侏罗统至白垩系中 ,共识别出七个 3级层序 ,包括 1个Ⅰ类层序和 6个Ⅱ类层序。重新建立了该区层序地层年代格架。层序地层的研究表明 ,盆地的演化可划分为具深切谷的碎屑陆架阶段 ,碳酸盐台地与海绵礁形成阶段 ,滞流的碎屑陆架阶段 ,无障壁海岸的碎屑陆架阶段和具障壁海岸的碎屑陆架

The Jiama intra-arc basin located in the Gangdise tectonic belt, Xizang was formed with the development of the Jiama island arc, where there occurs a succession of littoral and shallow-marine active marginal sediments consisting of clasticrocks and sponge-reef limestones. The Upper Jurassic and Cretaceous strata in the basin may be grouped into seven third-order sequences including one type 1 sequence and six type 2 sequences. The stratigraphic framework has been reconstructed for the basin. The study of sequence stratigraphy indicates that the basin has experienced five stages of evolution: (1) deeply incised siliciclastic shelf; (2) carbonate platform and sponge reefs; (3) stagnant siliciclastic shelf; (4) non-barrier siliciclastic shelf, and (5) barrier siliciclastic shelf.