Qaidam is a plateau basin, with an elevation of 2600-3200 m, under climate arid. All the run off of about 440-500 million m³ yearly is converged into the river-sealed basin owing to reversed drainage, therefor, salt-water balance of the region mainly depends on evaporation. The deposition of salts in this basin have been started at least since Tertiary. In the salts deposited, besides large amounts of halite, carnatite and gypsum, those of B, Li, and Sr had also been enriched.