Intergrative Stratigraphy Of The Lower Wujiapingian Of Upper Permian In Southeastern Yunnan

In this paper, the study area is located in Wenshan area of Yunnan(Southeastern Yunnan), and the study eras is the early Wujiaping of Late Permian. It is focused on the research about high resolution integrative stratigraphy and isochronous stratigraphy frame.The stratigraphic frame of the ragion is established through the integrative stratigraphy which includes and comparison of sequence. Based on these results, we discuss spatial distribution of the sedimentary system to provide basic information about mineral resouces exploration.The following achivement was obtained:1. Lithostratigraphy:It is mainly about the lithostratigraphic division of Permian in researched area. The Permian and adjacent strata of the Southeeast of Yunan are divided into:Huanglong Formation,Maping Formation,Yangxin Formation,Emeishan basalts,Longtan Formation,Wujiaping Formation,Ximatang Formation,Feixianguan Formation. And the lithologic festures and their distribution are described.2. Biostratigraphy:Fossils are important for stratigraphic division and comparison.We collected fossils including fusulinid,coral and brachiopod during the measure of sections,also lots of previous data. Based on previous data and identifing fossils,the Permo-carboniferous system is divided into8fusulinid fossil zones,3conodont fossil zones and2coral fossil zones.3. Sequence stratigraphy:The lower Longtan Formation composes of low-energy muddy coast-restricted shallow marine ferriferous rock, sandstone, mudstone interbedded by coal seam. Unconformity and extensively developed coal seam are the critical boundaries of the system tracts.There are three types of the Parasequences:Parasequences consisting of tidal flat-swamp clastic rock-coal seam, Parasequences consisting of tidal flat mudstone,and Parasequences consisting of neritic-sub tidal zone aluminum rock. One and half sequences have been divided on the sequence feature and superposition pattern of the parasequence.Through the comparison of sequence,which includes degree of sequence development,interfacial characteristic,degree of systems tracts development, composition of systems tracts,the stratigraphic frame of the ragion is established. The analyzing the sequence stratigraphic correlation leads to the conclusion that transgression came from the northeast and the sea shelf is plunging northeastward.