张家界地区中晚寒武世岩相古地理特征

张家界地区中晚寒武世岩相带3分格局明显，自NW向SE依次为台地相、台缘斜坡相和陆棚相。3相区之间分别以花坦－张家界、古丈－张家界深大断裂为界。台地相欧孔王溪组属邻近盆缘陡坡地带类似于深水陆棚沉积，重力沉积发育；娄山关组北西小区记录了由台地边缘浅滩→局限台地潮坪→台地边缘浅滩的变迁过程；而东南小区则属台地边缘与斜坡的过渡地带。台缘斜坡相区敖溪组反映了缓慢的海退过程，沉积环境由陆棚向陆棚内缘带变迁；车夫组属台地前缘斜坡带，重力沉积转化为蚀流沉积；比条组为背景沉积综合产物，反映了台地前缘斜坡上带环境，陆棚相区探溪组旋回性明显。反映了陆棚内缘沉积特点；田家坪属台缘斜坡下带－陆棚内缘环境，沉积了一套多具鲍玛层序的远源风暴岩。各自有其岩石类型组合特征及沉积构造特征，并讨论了岩相古地一的演化规律。

THE CHARACTERISTICS OF LITHOFACIES AND PALEOGEOGRAPHY FROM MIDDLE TO LATE CAMBRIAN PERIOD IN ZHANGJIAJIE,HUNAN

The lithofacies from middle to late Cambrian period can be obviously classified into 3 belts,. From northwestern to southeastern , they are successively platform facies, epiplatforn slope facies and shelf facies. Among the 3 facies, the Huayuan-Zhangjiajie and Guzhang-Zhangjiajie great fractures separate them. Kongwangxi formation in platform facies may be sediment in shelf near the steep belt of basin edge which is similar to the watev-deep continental shelf sediment, develop gravity sediment. The northwestern area of Loushanguan formation recorded the changes of sediment environment from epiplatform facies, tidal flat to edge of platform, and the southeastern area is the transition area from edge of platform to slope. The Auxi formation of epiplatform slope facies reflected the slowly process of regression, and the sediment environment changed from shelf to the inner edge of shelf. Chefu formation is the turbidity current sediment of front edge of platform slope. Bitiao formation is deposit of the background sediment to gravity current sediment, and represents the environment of upper belt of front edge of platform slope. Tanxi formation of shelf facies has the obvious cycle of sediment and reflects the feature of the inner edge of shelf. Tianjiaping formation belongs to the sediment environment of low belt of epiplatform slope to inner edge of shelf, and deposited a series of far resource storm deposit with Bouma sequences. All above formation have their own petrologic features and sediment structural feature. The authors have also discussed the evolution law of lithofacies and palaeogeography.