四川巴塘县茶洛地区温泉及间歇喷泉水化学特征和成因分析

温泉的水化学和成因研究对地热资源的开发利用有重要意义。四川巴塘县茶洛温泉的分布受茶洛—松多断层带的控制,沿北东—南西向的河流两岸出露,附近出露三叠系灰岩、砾岩和燕山期花岗岩。在温泉区出露有近20个泉眼,对其中10个泉眼进行采样测试。受出露点冷水混入的影响,东北部的两个泉眼温度为45~51 ℃,中西部地区的泉眼温度为77~89 ℃,部分为沸泉泉眼;各泉眼流量为0.01~1.8 L/s;pH值为6.1~8.1,矿化度为0.39~1.06 g/L,F^-含量为15~22 mg/L,偏硅酸含量为69~356 mg/L。泉水主要阳离子为Na⁺、K⁺和Ca²⁺,主要阴离子为 {\mathrm{CO}}_3^{2-}、 {\mathrm{HCO}}_3^{-}、Cl^-和 {\mathrm{SO}}_4^{2-},水化学类型为HCO₃-Na型。氢氧同位素数据表明,研究区地下热水来源于大气降水,补给高程约为4 400~4 800 m,补给区年均气温在-10 ℃左右。利用SiO₂温标估算茶洛温泉热储层温度约为150~200 ℃,热水循环深度约为2 810~3 480 m。茶洛温泉为大气降水入渗后在地下深循环过程中被大地热流加热,再沿断层带在河谷涌出地表而形成的温泉。在河流西北岸分布有灰岩,地下水溶蚀形成空洞,来自浅处的冷水和来自深部的热水在空洞中混合并被加热至沸点,导致热水间歇性上升喷出地面,形成间歇喷泉。

Hydrogeochemical characteristics and genetic analysis of the Chaluo hot springs and geysers in the Batang County of Sichuan Province

Hydrochemical and genetic investigations of hot springs are of great significance for the exploitation of geothermal resources. The Chaluo hot springs are located along a river valley in the Batang County of Sichuan Province. The occurrence of the springs is controlled by the Chaluo-Songduo fault. Triassic limestone, conglomerate and granite of the Yanshan Period occur near the hot spring. There are about twenty spring vents on both sides of the river, some are boiling vents and at least two are geysers. Hot water samples were taken from 10 vents. Due to different rock conditions and cold water mixing status, the temperatures of the two vents in the northeastern region ranged from 45 to 51 ℃, while in the central and western areas the vent temperatures ranged from 77 to 89 ℃. The discharge of the vents ranged from 0.01 to 1.8 L/s. The main chemical characteristics of the hot spring water are: pH=6.1-8.1, TDS=0.39-1.06 g/L, F^-]=15-22 mg/L, and H₂SiO₃]= 69-356 mg/L. The major cations in the hot springs are Na⁺, K⁺ and Ca²⁺, and the major anions are {\mathrm{CO}}_3^{2-}, {\mathrm{HCO}}_3^{-}, Cl^- and {\mathrm{SO}}_4^{2-}. Most of the hot water samples are of HCO₃-Na type. The δ²H and δ ¹⁸O of the hot spring water samples indicate that the hot water is meteoric in origin. The recharge altitude was estimated to be 4400-4800 m, and the average temperature of the recharge area is about -10 ℃. The estimated temperature of the geothermal reservoir is 150-200 ℃, and the calculated depth of the thermal ground water is 2810-3480 m. The geothermal waters of the Chaluo hot springs receive recharge from precipitation infiltration. Heated by heat flow during the deep circulation process, the hot waters emerge along the fault zones in the river valley. Thick limestones near the springs are dissolved by groundwater to form cavities, inside which the shallow cold and deep hot waters are mixed and heated to boiling temperature forming geysers.