Taponomic Environment Of Middle Triassic Qingyan Fossil Library In Guiyang,Guizhou

As earliest named biota, Qingyan fossil library was called Qingyan biota, found in Qingyan Guizhou,existed in Xinyuan formation of middle Triassic Anisian. As the Qingyan fossil library is the key to study the bio recovery and radiation, further research on Qingyan fossil library has very important scientific significance.Preliminary discussion for ecology and taponomic environment of Qingyan fossil library was prog ressed based on previous research and field surveying, in addition, the sedimentology, paleobiology and geochmistry were used to it.Taponomic Environment of Qingyan fossil library was Carbonate platform margin slope-siliciclastic basin edge by the research of layer(Yingshangpo and Leidapo) and the down stage(Yingshangpo) was platform margin slope,the up stage(Leidapo) was basin edge.Through the analysis of the biological living environment, the living environment was very broad from shoreland-continental shelf but the main environment were platform margin and inside.Combined with analysis of characteristics of buried and carbonate microfacies research,the fossil were all composed of accumulation and transportation and the transportation was the major one.Long distance taponomic fossil mainly by the way of gravity flow carried from carbonate platform. The upper(Leidapo) was given priority to with granular flow and liquid flow and the bottom(Yingshangpo) was mainly for debris flow handling.The researches show that the sea level rised with strong reducible,the marine productivity and the biomass is high at Yingshangpo sedimentation period.The sea level was almost the same and the marine productivity was stable at middle and lower segment of Leidapo sedimentation period.The sea level and marine productivity dropped and lacked of organisms,the oxidation increased at the upper segment of Leidapo sedimentation period.Oxidation-reduction environment, paleoclimate and paleosalinity is based on the analysis of Th/U, Ni/Co, Sr/Cu and Sr/Ba.Hot climate in the study area are analyzed, the sedimentation period of Leidapo member was in quite and weak minded poor oxygen environment but the Yingshangpo member was in turbulent hypoxia environment. The paleosalinity at Yingshangpo sedimentation period is higher than Leidapo.