Hydrogeochemical Study And Metallogenic Conditions Analysis Of Mineral Water In Dongping,Fujian Province

Mineral water,as a green and environmental protection mineral resource,needs to be investigated and studied in detail before it is exploited.By investigating the stratigraphic lithology,geological structure,hydrogeological conditions and water quality and types of mineral water in the mining area,this paper points out that the formation process of Dongping mineral water is as follows:Atmospheric precipitation is the source of mineral water recharge and groundwater formed by precipitation infiltration migrates and stores in bedrock fissures and fault structures.Water-rock interaction occurs in the contact between groundwater and surrounding rock.These water-rock interactions make the characteristic components,metasilicic acid and strontium,enter groundwater.The enrichment of metasilicic acid and strontium makes groundwater in Dongping area become metasilicic acid-strontium mineral water.In this paper,Arcgis software is used for hydrological analysis of the study area.The steps of generating DEM,hydrological analysis process and DEM rendering are described in detail,and some parameters for reference are listed.Using the water quality test results list and Piper three-line diagram,it is pointed out that the cations in groundwater of mining area basin are mainly Ca²⁺,Na⁺,the anions are mainly HCO₃^-,the main hydrochemical type is HCO₃-Na·Ca and the water quality is good.The hydrogeochemical processes in the basin mainly include rock weathering,lixiviation and cation exchange.By drawing Gibbs diagram,it is pointed out that the formation of groundwater components in the basin is mainly controlled by rock weathering and atmospheric precipitation.By analyzing the relationship between TDS and major ions,it is considered that Ca²⁺,Na⁺,HCO₃^-obtained by lixiviation contributes greatly to TDS.According to the proportional relationship between the main ions,it is considered that calcium feldspar and albite are two kinds of silicoaluminate minerals which are more dissolved in groundwater.The alkali index proves the occurrence of cation exchange between groundwater and surrounding rock.The main characteristic components of mineral water in the basin are metasilicic acid and strontium,metasilicic acid mineral water occurs in loose pore,metasilicic acid-strontium mineral water occurs in bedrock fissures and structural fissures.According to the analysis of characteristic components,there are several understandings as follows:Firstly,the size of pH has certain influence on the content of metasilicic acid in water.The smaller the pH,the higher the content of metasilicic acid in groundwater.Secondly,in groundwater with high Ca²⁺content,strontium content is also high.Finally,the content of metasilicic acid in groundwater increases with the increase of TDS concentration.Because of the high TDS content in bedrock fissure water and structural fissure water,metasilicic acid can be enriched in bedrock fissures and structural fissures.The influencing factors of mineral water formation in the basin include bedrock fissures,fault structures and stratigraphic lithology.The silicoaluminate minerals such as feldspar,mica and strontium in intrusive rocks provide sufficient material sources for metasilicic acid and strontium in mineral water.According to the equilibrium phase diagram of minerals,it is proved that the hydrolysis product of the reaction between aluminosilicate minerals and groundwater in the basin is kaolinite.In addition,this paper considers that the intrusion of magmatic rocks enriches a large amount of strontium near the contact zone between granite and metamorphic rocks,so strontium can be enriched in groundwater of the contact zone between intrusive rocks and metamorphic rocks.The enrichment of strontium and the high content of metasilicic acid make the groundwater near the contact zone become metasilicic acid-strontium mineral water.It is suggested that when developing and producing mineral water,the aquifer in contact zone should be found by opening holes in metamorphic rock area,which is beneficial to producing mineral water with high strontium content.