Distribution Of Foraminifera And (?) In The Permian At The Northeastern Part Of The Sichuan Basin And Its Environmental Significance

For a long period of geological time, the foraminifera and fusulinid play an important role in research of marine geology. As an important carrier of the marine sedimentary records of environmental information, which is one of the excellent biological indicators of studying the ancient environmental changes, and recovering the ancient marine environment. There are lots of micro fossils in the Changxing formation of the end of the Permian, Northeastern Sichuan Basin.The abundance of foraminiferaprovided rich material for the research of the thesis.In this thesis, non-fusulinid foraminifers and Fusulinids are been studied syst-ema tically. Non-fusulinid foraminifers of14genera and59species, and Fusulinids of5genera and5species are described. And as for these two sections that Tianba section and Jianshan section in the research area, their5respective fossil assemblages are e stablished.Biostratigraphic analysis shows the result as follows:(1) There is a striking similarity in the distribution of foraminifers. Sharp decline of living organisms occurred twice, but organisms all re-enriched right after the first decline. In contrast, there are no existence of foraminifers in the sectors after the second drop.(2) Eatablished a biostratigraphic zone by compared with Conodonts,after a comparative analysis between the studied sections to the Meishan section in Zhejiang province, it is found that extiction lines for the first mass extinction in Tianba and Jianshan respectively located in the2th and4th layer.(3)After a comparative analysis of carbon isotope, foraminifera analysis found that the size change rule of shell before in mass extinctions, foraminifera shells in miniaturization of different level.Through the carbon isotope change indications,The ancient Marine environment may lead to a high temperature oxygen zone ahead of foraminifera shells appear miniaturization phenomenon and Siberian volcanic activity may be lead to a series of the most important reason of disaster event.