广东惠州地热流体地球化学特征及成因分析OA

The Huangshadong-Longmen area in Huizhou,Guangdong Province,is located in the tectonically active zone at the southeastern margin of the Eurasian Plate and belongs to a high-value anomaly area of terrestrial heat flow along the south-eastern coastal China,where medium-low temperature geothermal resources are widely distributed.To reveal the genetic mechanism and evolutionary law of the geothermal system in this area,a systematic analysis was conducted on 29 groups of geothermal water samples collected from the Huangshadong-Longmen area in Huizhou,with discussions focused on the re-charge source,reservoir temperature,water-rock interaction,and heat source supply mechanism of the geothermal fluids.The results show that the hydrochemical types of geothermal water in the study area are dominated by HCO3-Na and HCO3-Ca types.The major cations are Na+and Ca2+,with concentration ranges of 6.7～325.4 mg/L and 9.3～66.15 mg/L,respectively,and the dominant anion is HCO3-with a concentration range of 150.77～682.17 mg/L.All the geothermal water is recharged by atmospheric precipitation,with the recharge areas distributed at an altitude of 747.6～1 284 m.The precipitation infiltrates through the deep,large faults and structural fracture zones and undergoes deep circulation.The average reservoir temperature of the geothermal system ranges from 118.6℃to 139.2℃.The major ions of the geothermal water are derived from the leach-ing of carbonate and silicate minerals,accompanied by significant cation exchange.The heat source of the study area is the su-perposition of the regionally high terrestrial heat flow and the radioactive heat generation of the underlying Yanshanian gran-ite.The deep,large faults and zones with well-developed structural fractures serve as the main migration channels for geother-mal fluids,and control the development of geothermal reservoirs and fluid circulation.