Reseach Of The Oringin Of Salt Deposits And The Salt Forming Era In Jiangcheng Mengyejing

Potash is closely related to agriculture. China as an agriculture coutry, Most of the poatsh is imported. As a country which is rich in resources, the job of finding much more potash is imminet. Mengyejing salt is the only ancient chloride solid potash deposit in china. The exploitation of potash had a long history. Since last century60’s, scholars and geologists have conducted extensive research on Mengyejing potassium salt deposit, they studied about the basin formation and evolution, fault structure zone, and the genesis of the deposite, many geological data was accumulated at that time. But unfortunately,as to the genesis of the deposite, until now, there are still no exact internal salt characteristics which are used for explaining the sedimengtary characteristics and the formation of salt environment. There are also still no basin model used for descriping the oringin of salt deposits. As for the salt formation time,though the predecessors refered to it,they had no detail study.This paper take Jiangcheng Mengyejing as study area. We conducted a geological exploration of the Mengyejing area. To constrain the origin of the brine that formed sequences of salt mineral deposits in Jiangcheng Mengyejing we collected several salt samples and measured the strontium isotope composition of some salt minerals in the potash deposit, and then we measured the content of Rb and Sr to correct the strontium isotope ratio to discuss the salt forming era, And then, we put forward a salt formation model based on the salt forming time and the previous geological data. The result showed that the brine of the salt mineral deposits in Menyejing was mostly from seawater and the salt forming Era was Jurassic.The salt which had more boulder clay and poor crystallization degree was the primary salt.They were mixed by continental water in Miocene,and then recrystal the salt which had little boulder clay and good crystallization degree.