西藏雅鲁藏布江缝合带含有从砾石级到几十平方千米大小的二叠纪灰岩体,它们没有完整的地层层序,与围岩形成混杂或滑杂堆积,长期以来对其来源的解释存在争论。本文通过对灰岩体的动物群类型、古生物地理区系及其岩石学特征等方面进行研究和比较,认为雅鲁藏布江缝合线一带的二叠纪灰岩体总体上都呈现出冈瓦纳冷水型与华夏暖水型动物群混生特点,应形成于相同或类似的沉积环境。根据珊瑚、竺蜓、腕足类等动物群大致分为与南方冈瓦纳大陆北缘内陆棚相动物群比较接近和与更靠近古赤道区的拉萨地块动物群较为接近两种类型,其时代从早二叠世晚期至长兴期不等。灰岩体主要由肉红色或灰色纯生物碎屑灰岩组成,不含或含有很少的陆源碎屑,均孤立地分散于中生代地层中,与围岩往往呈断层接触,断层带或灰岩夹层中经常有玄武岩或其他火山岩。因此,灰岩体可能为位于冈瓦纳大陆北缘外陆棚上小型碳酸盐台地或新特提斯洋最初裂解带上的海山型碳酸盐岩沉积,受后期印度—欧亚大陆板块碰撞作用而成为外来体夹于缝合带的其他海相沉积中。 The Yarlung Zangbo suture in Tibet contains Permian limestone bodies ranging from gravel to tens of square kilometers. They do not have complete sequence stratigraphy and form mixed or slippery sedimentary accumulation with surrounding rocks. There has been controversy over their sources for a long time . Based on the study on the fauna, the paleontology and fauna of the limestone, and its petrologic characteristics, the Permian limestone in the Yarlung Zangbo suture shows that the Gondwana cold water and Huaxia warm-water fauna mixed characteristics should be formed in the same or similar depositional environment. According to the coral, zhu dragonflies, brachiopods and other fauna are roughly divided into two groups with the Lhasa block fauna that is closer to and closer to the ancient equatorial zone in the northern margin of the southern Gondwanaland, The times ranged from the late Early Permian to the Changxing period. Limestone bodies are mainly composed of pure red or gray pure bioclastic limestone with little or no terrigenous debris dispersed in the Mesozoic strata in isolation and are often in contact with faults, fault zones or limestones Basalt or other volcanic rocks are often found in the interlayer. Therefore, the limestone body may be seamount type carbonate deposition on the small carbonate platform in the margin of the northern margin of the Gondwanaland continental shelf or in the initial tectonic zone of the Neo-Tethys Ocean. Due to the late Indo-Eurasian plate Collision and become foreign body sandwiched in other marine sediments.