Geological Characteristics and Its Origin of Gypsum Deposits in Pingyi Basin in Shandong Province

Pingyi basin located in the south of southeast Mengshan mountain in Luxi fault-block uplift.Mengshan block located in northern edge of Pingyi basin.Formation,morphology and evolution of this basin are strictly controlled by this fault.Gypsum deposits in Pingyi basin occurred in the middle part of the second section of Paleogene Guanzhuang group.Mesozoic Yanshan movement,accompanied by volcanic activities had been sinking along south side of Mengshan fault.It has laid the foundation for the formation of Pingyi basin.The southeast part of Mengshan fault has been sinking from Cenozoic.It will provide space for sedimentary of strata in lower Tertiary Guanzhuang group.Thus,Pingyi basin has become a favorable location for the formation of gypsum deposits.Through constrast of chemical composition of rock and analysis on material sources,it is regarded that gypsum deposits in Pingyi basin are multi-material and multi-stage continental salt evaporite basin.