滇西洱源盆地高温热泉水文地球化学特征及其地质意义OA

The Eryuan Basin is rich in high-temperature geothermal resources;however,excessive fluoride ion content has seriously restricted the development and utilization of these resources.The aim of this study was to analyze the hydrogeochemical characteristics and genetic mechanisms of high-temperature geothermal groundwater in the Eryuan Basin.A total of 25 geothermal water samples were collected.Based on hydrogeochemical testing and isotope analysis,self-organizing map neural network clustering,hydrogeochemical graphical methods,and ion ratio analysis were combined in this study.The average temperature of geothermal groundwater in the Eryuan Basin is 73.25℃,with a pH of 6.20-8.20,TDS of 326-1 197 mg/L,and hydrochemical type of HCO3-Na.The hydrogeochemical characteristics of geothermal water are dominated by water-rock interactions influenced by the dissolution of silicate rocks and cation exchange interactions.Based on classification results from the self-organizing mapping neural network,the genetic mechanism of fluoride-enriched geothermal groundwater was analyzed.The fluoride ions were found to mainly originate from the dissolution of fluoride-rich minerals,and the enrichment process was closely related to pH,cation exchange interactions,and competitive adsorption interactions.The geothermal water is mainly recharged by atmospheric precipitation in the eastern mountainous areas,with a recharge elevation of 2 500-4 192 m and circulation depth of 2 625-5 286 m.The quartz geothermometer method was used to estimate the geothermal reservoir temperature to be 105-166℃.This study revealed the hydrogeochemical characteristics and mechanisms of high-temperature and high-fluoride geothermal water in the Eryuan Basin,providing a theoretical basis for the efficient development and utilization of geothermal resources in the region.