贺州大汤温泉的形成条件及其水化学特征

Forming Conditions and Hydrochemical Characteristics of Datang Hot Spring,Hezhou City

为了合理开发和保护贺州市南乡镇大汤温泉资源,通过对温泉区地理环境和地质条件的分析来探讨温泉的形成条件,并对温泉水质的化学成分进行测定。贺州市南乡镇大汤地热田是一个带状热储,区域内的几条深大断裂构成其地下热水储热和深循环通道。该温泉以大气降水补给为主,补给区为周边分水岭。由于分水岭的地势较高,地下水在获得降雨补给后,有足够的水头压力沿着构造断裂实现由浅至深再由深至浅循环。在循环过程中,地下水通过热传导从深部地壳中获得热量,并通过与围岩发生的地球化学作用而获得丰富的微量元素。水化学分析表明,南乡温泉出露的热水不仅矿化度低、且富含氟、含偏硅酸和多种有益的微量元素,其氟和偏硅酸含量可达矿水命名标准,具有很高的医疗价值。

In order to reasonably develop and protect the hot spring resources of Datang geo- thermal field in Nanxiang town of Hezhou city, the formation of hot spring based on the a- nalysis of geographical and geological conditions, and the chemical composition of water is studied and analyzed. Datang geothermal field is a zoned reservoir. Several deep and large fractures in the region form the transportation conduit and storage space for the hot water. Rainfall is the main water resource of the hot spring and the watershed around the spring is its recharge area. Due to the high hypsography of the watershed, the groundwater can circu- late from shallow aquifer to deep fractures by high water pressure. During the circulation, the groundwater obtains heat from deep strata through heat convection. Moreover, a series of complex geochemical reactions between ground water and deep rocks results in a lot of trace elements dissolved into the hot water. Hydrochemical monitoring data indicats that the hot water is rich in fluorine, metasilicic acid and various beneficial trace elements but low TDS. The concentrations of the fluorine and metasilicic acid in the hot water both reach the standard of mineral water, which indicates the hot spring is suitable for balneotherapy.