Faculty of Geosciences and Environment Engineering, Southwest Jiaotong University
Kunming Natural Resources Comprehensive Survey Center, China Geological Survey
Innovation Base for Eco-geological Evolution, Protection, and Restoration of Southwest Mountainous Areas, Geological Society of China

温泉的水化学特征和成因机制研究对中低温地热资源的开发利用具有重要意义。云南落漏河流域温泉分布受隐伏断裂带控制，沿落漏河分布于河谷两岸，出露于第四系松散堆积物和二叠系玄武岩地层，温度介于34.5~50.0℃，属于中低温热水，pH为7.62~9.73，溶解性固体总量介于262~702 mg/L。通过采集落漏河流域内温泉热水和周边浅表冷泉水样，开展水化学成分和氢氧同位素测试，基于水文地球化学方法探讨温泉及地下水的水文循环过程、水化学演化及其成因模式。结果表明，受HCO3-Ca型浅层地下冷水混合的影响，温泉水化学类型为HCO3-Na型，温泉热水和地下冷水化学组成受硅酸盐和碳酸盐矿物溶滤控制。氢氧同位素分析指示温泉热水和地下冷水主要接受大气降水补给，补给高程为2 007~2 307 m，补给区域为河谷西北部马耳山、北部锅盖山和中部左家山等山脉。通过二氧化硅地热温标、硅−焓混合模型和多矿物平衡模拟估算的温泉热储温度为68.4~150.0℃，冷水混合比例为77.9%~90.5%。落漏河流域温泉成因模式大致为：大气降水沿裂隙或岩溶通道下渗，历经深部地下循环被大地热流加热，循环深度为2 872~3 724 m，而后在高温和冷、热水密度差的驱动下沿白莲村隐伏断裂带上涌，在第四系地层以中低温温泉形式出露。研究成果可为落漏河流域温泉开发利用以及探索同类型中低温地热资源开发潜力提供依据。

The hydrochemistry and genesis mechanism of thermal springs hold great significance for the exploitation and utilization of low to intermediate temperature geothermal resources. Under the influence of a concealed fault zone, thermal springs in the Luolou River basin, Yunnan Province, are distributed along both sides of valleys and exposed in Quaternary loose deposits and Permian basalt strata. It belongs to low to intermediate temperature thermal spring water, with temperatures ranging between 34.5 and 50.0℃, pH is between 7.62-9.73, TDS is between 262-702 mg/L. Based on the hydrochemical and isotopic tests of thermal spring samples and nearby cold water samples from the Luolou River basin, this study explored the hydrological cycle, hydrochemical evolution, and genesis mode of the thermal springs and groundwater using the hydrogeochemical method. The results show that the thermal spring water has a hydrochemical type of HCO3-Na due to the mixing of HCO3-Ca type shallow cold groundwater. Furthermore, the chemical compositions of the thermal springs and cold groundwater are influenced by the leaching of silicate and carbonate minerals. Hydrogen and oxygen isotope analysis indicates that the thermal springs and cold groundwater are primarily recharged by meteoric precipitation, with recharge elevation ranging from 2007 to 2307 m. The recharge area is the mountain range of the valley, such as the northwest Maer Mountain, the north Guogai Mountain and the central Zuojia Mountain. The thermal springs exhibit reservoir temperatures ranging from 68.4 to 150.0℃, as estimated using silica geothermometers, silica-enthalpy mixing model, and multi-mineral equilibrium simulations. The mixing ratio of cold water is estimated to be 77.9%-90.5% by silica-enthalpy mixing model. Regarding the genesis mode of thermal springs in the Luolou River basin, the atmospheric precipitation infiltrates along the fissure or karst channel, and is then heated by terrestrial heat flow during deep underground circulation with a depth of 2 872-3 724 m. Afterward, driven by the high temperature and the density difference between cold and hot water, the water upwells along the concealed Bailiancun fault zone, exposed as low to intermediate temperature thermal springs in the Quaternary strata. The results of this study will provide a basis for the exploitation and utilization of hot springs in the Luolou River basin and exploring the exploitation potential of the same type of low to intermediate temperature geothermal resources.

国家自然科学基金项目 (42072313，42102334)；中国地质调查局项目 (DD20230483，DD20230098)；四川省科技厅项目 (2022NSFSC0413，2023YFS0356)

罗欢，刘振南，马一奇，等. 云南落漏河流域温泉水化学特征及成因模式[J]. 煤田地质与勘探，2024，52(1)：56−69.

LUO Huan，LIU Zhennan，MA Yiqi，et al. Hydrochemistry characteristics and genesis mode of hot springs in the Luolou River basin, Yunnan, China[J]. Coal Geology & Exploration，2024，52(1)：56−69.