The margin of the carbonate platform of the Middle and Upper Ordovician, Tazhong area, Tarim Basin is characterized by a well-developed rimmed depositional system which consists of various types of grain banks and organic reefs.

• 塔里木盆地塔中地区中上奥陶统碳酸盐岩台地边缘以发育良好的多种粒屑滩和生物礁组成的镶边沉积体系为特征.