Study On The Longge Formation Carbonate Sedimentary Microfacies In Rongma County Of Tibet

Paper based on the?1:50000 Rongma region of four control union test project?,we have a study of The Longge sedimentary facie in Rongma County of Tibet.Because the deposition of Permian in the study area study,previous researchhas No one shows any interest in,do have far away from the Rongma areaother maps.At the same time the Permian Longge formation as a set of carbonate deposition,has a certain reference for future oil and gas exploration prospects,and the microfacies study has not been reported.So the research on regionalchoice.Through detailed stratigraphic section field research,Field measurements of the three Longge Formation profiles,respectively,PM002,PM003,PM006,belonging to the formation under section Longge,the middle and upper segments.In order to more fully reflect the Longge Formation characteristics,the three cross-sectional studies were described and discussed in detail the characteristics of each section,on the basis of the measured cross-section of the Longge Formation conducted an overall carbonate sedimentary microfacies Research.According to Longge carbonate rocks colors,combined with the characteristics of sedimentary features and research containing fossils that Longge limestone formed mainly in sedimentary carbonate platform environment.Mainly by the gray and black-gray medium to thick-bedded limestone,oolitic limestone,gray medium to thick-bedded micritic limestone,local folders conglomerate,Central also see colluvial rock;their belonging to different carbonate rocks microfacies.According to Longge matrix carbonate rocks of particles of different types and fillers,as a Formation based on the entire cross-section is divided into Longge platform marginal slope facies carbonate rocks restricted platform,open platform,platform margin shoal phase,the platform margin reef with five sedimentary facies,and observed under a microscope based on the sedimentary facies are further divided into?containing bioclastic marl,bioclastic wackestone,bioclastic packstone,the debris packstone,ash particles in the debris rocks,clumps of particles of limestone,many types of particles oolitic limestone,reef limestone nine micro-phase,in order to restore the depositional environment.Three cross-section has a good micro-phase continuity,even after up to three sectional study analysis that Ma Rong district Longge Formation in the orderly development of micro-phase form a cross-section on the "platform-Ramp-mesa"complete water cycle consisting of retreat.