Study On Formation Mechanism,exploitation And Utilization Of Drinking Natural Mineral Water In Anhui Section Of Tanlu Fault Zone

Drinking natural mineral water is an important water resource.Understanding its formation mechanism and hydrochemical characteristics is of great significance for the rational development and utilization of natural mineral water.This paper takes the Anhui section of the Tanlu fault zone as the target area and the Hefei area as an example,and analyzes the mechanism of the formation of mineral water from three aspects:stratum lithology,geological structure and hydrogeochemical conditions;And water quality and permissive yield of the mineral water are evaluated;the main conclusions are as follows:?1?The mineral water in the area is mostly neutral fresh water.The cations are dominated by Ca²⁺and Na⁺,and the anions are dominated by HCO₃^-.Except for the“H4 deep wells in the hot springs sanatorium”which is SO₄^2-type water,and the rest are HCO₃^-type waters.The characteristic components of mineral water in the study area are mainly Sr and H₂SiO₃.Only 1 group is Sr-Zn type mineral water,and the characteristic components of 3 groups are not stable.?2?The complex fracture network in the area provides good access and storage space for the supply,runoff and circulation of mineral water.The main water control and diversion structures in the area are North-north-east,north-east,and near-east-west faults,followed by north-south and north-west faults.?3?Both clastic and magmatic rocks in the Hefei basin have a high background of SiO₂ and Sr,which is the material basis for the formation of mineral water.The formation type of mineral water is fracture type,that is,the water-conducting fractures developed in each rock formation are the main controlling factors and migration channels for the formation of mineral water.According to the results of the reverse path simulation,the unique chemical composition of mineral water in the area is the result of the combined action of leaching,cation exchange and concentration of groundwater.Na⁺is mainly derived from plagioclase,rock salt and cation exchange.Ca²⁺is mainly derived from plagioclase,anorthite and cation exchange.The dissolution of feldspathic minerals simultaneously produces H₂SiO₃ and Sr,forming Sr-H₂SiO₃ type mineral water.?4?Among the 32 groups of mineral water samples,9 groups have poor water quality;1 group is extremely poor;and the remaining water quality is good.The main reasons for the poor water quality are sediment in the water,more total coliform bacteria and excessive nitrate content.The total permissive yield of mineral water in the area is 12154 m³/d,while the actual extraction volume is 177 m³/d,and the exploitation and utilization degree is very low.