Hydrochemical characteristics and formation mechanism of metasilicate mineral water in a Cenozoic basaltic aquifer in Zhangbei county, Hebei Province

This paper is the result of hydrogeological survey engineering.

Objective Metasilicate mineral groundwater is widely distributed in cenozoic basaltic stratum of Bashang area. It is of great practical significance to study the formation mechanism and water-rock interaction for rational utilization of water resources and development of mineral water industry in this area.

Methods The formation mechanism of metasilicate mineral groundwater in Cenozoic basalt in the research area was analyzed by collecting environmental hydrochemical samples such as groundwater and rainwater systematically and using mathematical statistics, ion ratio analysis, isotope analysis and other methods.

Results The metasilicate mineral water is mainly distributed in the groundwater recharge area of the front edge in the Bashang area on southern part of the county; And the mineral groundwater of study area is characterized by low mineralization while the main hydrochemical types of groundwater are HCO₃-Ca·Mg and HCO₃-Na·Ca; Also, metasilicic acid in groundwater originates from the hydrolysis of sodaclase, plagioclase, olivine and other silicate mineral in basalt, and is affected by rock mineral leaching as well as hydrochemical parameters cation exchange. According to the analytical results of hydrogen-oxygen isotope, it is concluded that the main source of groundwater recharge is local precipitation in summer, and the actual age of groundwater is between 15 a and 60 a.

Conclusions The formation of metasilicate mineral water in Bashang area of Hebei Province is related to the local special basalt geological structure and specific hydrogeochemical process.