Origin of brines and modern water circulation contribution to Qarhan salt lake in Qaidam basin, Tibetan plateau

摘要

Lake Qarhan is the largest salt lake and potassium salt resource mining base in china. Understanding the origin of brines and the contribution of modern water circulation is extremely important to the sustainable development of the salt lake. Comprehensive tools including isotope, hydrochemistry and numerical simulation had been performed. Results suggest that brine groundwater in the salt lake area is the result of ancient brines migrated from the western Qaidam Basin due to the uplift of the western basin in the geological past. Shallow phreatic aquifers in the salt lake area are also recharged by the modern surface water in the flood period. The contribution of modern groundwater circulation to the salt lake area is very limited with only 3% of the total quantity of groundwater discharge for the watershed.