Chemical characteristics and genetic model of mineral water in Dabie Mountain area of Anqing City

Anqing Dabie Mountain area is located in the east side of Dabie Mountain orogenic belt. There are 2 strontium metasilicate mineral water points, 1 strontium mineral water point and 3 metasilicate mineral water points being studied. The genetic model is further discussed based on the analysis of the hydrochemical and isotopic characteristics of mineral water in the area. The main ions in the cold spring (well) water(AH1、AH3、AH4、AH5、AH8 and AH9) are Ca²⁺, Mg²⁺, Na⁺ and HCO₃^-, the hydrochemistry type is HCO₃-Ca, HCO₃-Ca·Na or HCO₃-Ca·Mg, and the total dissolved solid is 90~239 mg/L. The main ions in hot spring water (AH2, AH6 and AH7) are Na⁺ and SO₄^2-, the hydrochemistry type is SO₄-Na or SO₄·HCO₃-Na, and the total dissolved solid is 253~426 mg/L. Based on the δ²H and δ¹⁸O values, the elevation of the recharge area of cold spring water is estimated to be 217~346 m, and the average temperature of the recharge area is 17.7 ℃. The elevation of the hot spring's recharge area is 457~668 m, and the average temperature of the recharge area is 12.6 ℃. The mineral water in the 9 places is supplied by atmospheric precipitation, which circulates along the fault zone and fissure zone to a certain depth and is exposed in the valley. The results show that the circulation depth of hot spring groundwater is large, the time of water rock interaction is long, and the TDS value and characteristic chemical component content of hot spring groundwater are higher than those of cold spring groundwater.