Source, Migration, and Occurrence of the Potassium Rich Subsurface Brines in the Sichuan Basin

There are multiple salt-forming stages, from the Sinian to early Cretaceous, and multiple stable halogen layers in the Sichuan Basin. Some potash deposits have been found and the potassium rich subsurface brine structure also has entered the exploration stage. By the theory of modern sedimentology, geochemistry, hydrology geology, structural geology, mineral deposit geology, and the comprehensive analysis of outcrop, drilling, seismic,  water chemistry, and geochemical data, the basin tectonic background of potassium bearing strata is reconstructed, and the main potassium sedimentary strata, the main types of sedimentary facies, the distribution of sedimentary facies, and paleogeography are found out. Combined with the hydrogeological data, it is thought: (1) the combination of the regional depositional model and the potassium rich subsurface brine genesis mechanism, and potassium element enrichment research and the rule of formation, migration of brine can effectively predict the regional potassium target zones and regional halogen containing structure delineation; (2) the marine evaporate basin, developed in geological period, is the main source of potassium rich brine; (3) the multi-period fault and fold structures, developed during when the basin formed, control the migration and accumulation of the potassium rich subsurface brine; and (4) pores and fractures, widely distributed in carbonate rocks of the basin, provide a good space for the potassium rich subsurface brine storage.