A tentative discussion on exploration model for potash deposits in basins of China

Potash salt is one of the mineral resources in great shortage in China. The prospecting of superlarge potash deposits has been a big puzzle within the mineral resource realm of China. Based on a synthetic analysis of research conditions in this aspect both in China and abroad,this paper deals with the principles for potash exploration in evaporative basin from macro-scale to micro-scale angles,which include:① to analyze whether there was a super-arid paleoclimate and considerable potassium supply during the long-term salt sedimentation,to ascertain if the paleo-lake water had developed to the crystallizing stages of potash salt owing to strong evaporation; ② to make certain in which strata potash was formed; and ③ to determine in which structural location of evaporative basin the potash deposits were formed; ④ to make sure which location of neotectonic transformation is favorable for exploring potash deposits under the modern landform conditions. The basic procedure for seeking potash deposits is as follows:first to find out the macroscopic potash-forming conditions,then to ascertain the microscopic potash-forming conditions,and finally to delineate the targets and distribution areas of the potential potash deposits and conduct validating work through drilling. The potash exploration in the Lop Nur Playa is one of the successful representative cases for potash deposit exploration in China. A potash-seeking model has been established on the relevant experience and studies of the potash exploration of the Lop Nur Playa,i.e.,first to conduct a comparative study of the potash-forming conditions between the Tarim and the Qaidam Basin and ascertain better potash-forming conditions for Lop Nur Playa,then to ascertain the targets for potash formation on the basis of relevant studies,and finally to carry out drilling for validating potash deposits in the target area. These achievements have made an important progress in discovering superlarge potash deposits in the Lop Nur Playa. In conclusion,the potash exploration and appraisal should follow the principle of "from known to unknown and from theory to practice and then from practice back to theory again". Through the perseverant study and absorqtion of theories and experiments available in China and abroad,the potash-seeking work will surely achieve new results in future.