云南兰坪盆地羊吃蜜温泉水化学特征与成因分析

Hydrochemistry and Formation of the Yangchimi Hot Spring in the Lanping Basin of Yunnan

位于云南省云龙县的羊吃蜜温泉自巨厚灰岩溶隙向外流出。温泉区沿河谷分布有第四系砂卵石,下伏地层为二叠系—三叠系碳酸盐岩。泉水共有泉眼3个,水温为35.6~35.9℃,流量约0.25 m^3/s,pH值6.3~6.5,总溶解性固体(TDS)为0.982~1.116 g/L,F^-含量为0.86~1.92 mg/L,偏硅酸为24~24.2 mg/L。泉水中的主要阳离子为Na^+、K^+、Ca^(2+)和Mg^(2+),主要阴离子为SO_4^(2-)、HCO_3^-和Cl^-,水化学类型为HCO_3·SO_4-Ca型。氢、氧稳定同位素显示,温泉热水来源于大气降水;估算的热水补给高程为2 500 m左右;地下热储温度为60~70℃;地下热水循环深度约为1 255 m。羊吃蜜温泉地处云南兰坪盆地红色含盐地层中突起的石灰岩分布区,地下水在补给区获得大气降水入渗补给后沿巨厚灰岩含水层经历深循环获得大地热流加热后上涌在河谷流出地面,是侵蚀岩溶低温温泉。

The Yangchimi hot spring is located in the Yunlong County of Yunnan Province, China, and flows out from the karstic fractures in limestone. Quaternary sands and pebbles occur along the river valley around the spring, and Permian and Triassic carbonates outcrop and underlie the unconsolidated sediments. There are three spring orifices with water temperature of 356-359 ℃, and the total flow rate is 025 m3/s.The chemical characteristic of the hot spring water is as follows： pH=63-65, TDS=0982-1116 g/L, F-=086-192 mg/L and H2SiO3=24-242 mg/L. The hot water belongs to HCO3·SO4-Ca type. The 2H and 18O isotopes of the hot spring water indicate that the hot water is of meteoric origin. The recharge altitude is estimated as 2 500 m or so, the temperature of the geothermal reservoir as 60-70 ℃, and the depth of the groundwater circulation as approximately 1 255 m. The Yangchimi hot spring lies in the carbonate in the uplift area surrounded by the redbed in the Lanping Basin in Yunnan. Groundwater receives recharge from infiltration of precipitation in the recharge area, undergoes deep circulation in the carbonate aquifer, obtains heat from heat flow and flows up to the surface in the river valley. It is an erosion karst hot spring with low temperature.