Gravity Flow Sedimentary Characteristics and Environmental Significance in Maokou Formation,Western Hubei Area

By use of strata study on the field outcrops and microfacies analysis indoor,types of gravity-flow deposits have been found in Maokou Formation Middle Permian,western Hubei province,which developed in carbonate slope depositional environment,from top to bottom slump deposits,debris flow deposits,particle flow deposits have been regonized,slump deposits developed in the Cili Jiang Ya section,Hunan province,particle flow and debris flow developed in the Ziqiu section Changyang country.Slump sediments is composed of the clutter angular-subangular calcirudite,poor sorting,grain-supported,short-range slump slided off from the platform margin;debris flow deposits formed of the calcirudite,gravel limestone,bioclastic micritic limestone,gravel is slightly alignment and sub-angular,sub rounded,gravel gradually reduced from bottom to top;particle flow is composed of the gravel limestone sediments,wackstone with miliolids,which developed 2 to 3 cycles and graded layer and wavy bedding.Gravity flow deposits in the study area controlled by the tectonic evolution,the characteristics of its spatial and temporal distribution of the area in the middle Permian is consistent with platform-basin deposition pattern,and it has certain significance for the Permian sedimentary evolution in the study area.