广东省从化温泉热矿水水化学与同位素特征

从化温泉位于广东省从化市东北,地处广从断裂带北东段,泉点沿NW及NE向次级断裂出露,热水出露于燕山期花岗岩中。温泉为中低温、偏碱性的低矿化水。热水中的阳离子以K⁺、Na⁺、Ca²⁺为主,阴离子以HCO^-₃为主,属于HCO₃-Na及HCO₃-Na·Ca水。热水中偏硅酸、氟含量较高,同时含有锂、锶、钡、硼酸等微量组分及放射性组分镭、氡。由D和¹⁸O组分表明热水起源于大气降水。根据玉髓温标计算的热储温度为82.14~93.52℃。由镭-氡法测定热水年龄,可知热水在地下滞留时间较短,循环较快,如开采量不大且采用采停交替的方式,有助于热水的可持续利用。

Hydro-chemical and Isotopic Characteristics of Conghua Hot Mineral Springs in Guangdong

The Conghua hot springs are located in the northeast of Conghua,Guangdong,and lie in the northeastern part of the Guangzhou-Conghua faulted zone.The springs occur in the small NW and NE trending faults in the granite of Yanshan Period.The springs are of low TDS,low-to-moderate temperature and weak alkali.The thermal groundwater is predominated by K, Na and Ca in cations and HCO₃ in anions and is of Na-HCO₃ and Na·Ca-HCO₃ types.The hot water has high concentrations of H₂SiO₃ and F,and is enriched in Li,Sr,Ba,HBO₂,Ra and Rn.Isotopes of D and ¹⁸O indicate that the hot water is of meteoric origin.The temperature of the geothermal reservoir estimated with a SiO₂ geothermometer ranges from 82.14 to 93.52℃.The residence time of the thermal groundwater estimated with Ra-Rn method is short,indicating a quick water circulation.The formation of the hot springs suggests that sustainable utilization of the hot water will be maintained if the total withdrawal rate is relatively small and an alternative pumping and non-pumping pattern is used.