Why does the northern Plateau of Tibet contain many brackish lakes?

The northern section of the Plateau of Tibet, known as the Qiangtang, contains many brackish lakes primarily because it is a semiarid region characterized by endorheic drainage basins.

In these basins, there is a specific climatic balance between the input of water through precipitation and the output of water through evaporation and seepage. Because these lakes lack external outlets, water that flows into them remains trapped. As the water evaporates, dissolved salts and minerals—often derived from the natural weathering of rocks—accumulate over time, leading to increased salinity. This process is common in high-altitude and semiarid environments where high evaporation rates and limited drainage prevent the flushing of salts, resulting in the formation of saline or brackish bodies of water.12