Cambrian evaporites are in a wide distribution and the brine with high salinity was found in northeastern Sichuan basin. The thick layer of halite and gypsum in Qinjiamiao formation of Middle Cambrian was found in Jiannan area. Well Jianshen 1 encounters the thick halite layer, with accumulative thickness of up to 120 m, with thin-bedded gypsum, and with the single –layer thickness of halite reaching a maximum of 80 m (might be thickened by squeezing), which overturns the previous conclusion that this area has not reached the halite deposition stage. The bromine to chlorine ratio is analyzed for halite debris (it is not easy to determine whether the halite debris is primary or secondary) and the Br × 10³/Cl value ranges mostly from 0.05 to 0.22, indicating that the seawater has not reached the stage of sylvite deposition. Comparing the percentages of the water-soluble and acid-soluble potassium ions, the potassium ion content of acid-soluble is found to be about 1.3-2.0 times higher than that of the water-soluble, and this may because the rock salt debris contains water insoluble potassium-bearing minerals. There are several wells that encounter the high salinity brine in northeastern Sichuan basin, with the K⁺, Br^-, and Li⁺ concentrations up to 4.6 g/L, 886 mg/L and 148 mg/L, respectively for well Tian 2 in Wuxi. In addition, this study reveals that the high Li⁺ content in the brine is neither from the concentration of sea water, nor from the leaching of salts. It may be related to the water/rock interaction, the volcanic activity or other hot water of deep sources. A comprehensive evaluation of sylvinite forming conditions in this area and the wide distribution of Cambrian salt-bearing basins in Asia indicate that the exploration in this area should be strengthened in the future.

northeastern Sichuan  /  Cambrian  /  bromine chloride coefficient  /  salt-forming environment  /  potassium-bearing salt forming condition