广西合山煤田隐伏地热找矿前景分析

Prospect Analysis of Concealed Geothermal Prospecting in Heshan Coalfield,Guangxi

为开发合山隐伏地热资源,对煤田地质勘查与开采资料进行“二次开发”研究。合山向斜东翼发育云斜煌斑岩,钻孔中见辉锑矿等低温热液矿物,具备热异常史。里兰矿8223巷等3处对流型地热异常,水温34.2~36℃(埋深300m±),传导型地热温度为48.7℃(埋深950m),属于对流-传导型温水地热系统。合山向斜为独立水文单元,外缘为岩溶峰林分水岭环抱,大气降水充沛。以压性为主的北北东向逆断层,延伸长切割深,为联通地壳深部的主导热构造;北北西向构造为张性断裂,以节理裂隙储热为主,岩溶孔隙型次之,导水赋水性强;传导型裂隙-岩溶型地热储厚度大,受各类断裂裂隙控制的岩溶发育,埋深适度,地温适宜洗浴;富水热储层的上覆和下伏地层均为隔水层,热量和水量不易流失逃逸,具备隐伏地热成矿条件。

To exploit the Heshan concealed geothermal resources,carried out coal geological exploration and mining data restudy.Mica-plagioclase lamprophyre has developed in east limb of the Heshan syncline;epithermal minerals such as antimonite etc can be seen in boreholes with thermal anomalous history.Three convective geothermal anomalies in the Lilan coalmine roadway No.8223 etc,water temperature 34.2~36℃,and buried depth 300m±;conductive geothermal temperature 48.7℃,and buried depth 950m,belong to convective-conductive type warm water geothermal system.Heshan syncline is an independent hydrogeological unit;exterior margin is encircled by needle karst dividing crests with plentiful atmospheric precipitation.Mainly compressional NNE reverse faults are long extended and deeply dissected,thus the main thermal conducting structure communicated with deep crust.NNW structures are tensional faults,heat accumulated mainly in joints and fissures,and karst pore type the second,with strong water conducting and water-bearing property.Conductive fissure-karst geothermal reservoir has large thickness;a variety of faults and fissures controlled karst are well developed,buried depth appropriate,geotemperature is suitable to bath;overlying and underlying strata of water-rich geothermal reservoir are all aquifuges,both heat quantity and water yield are not easy to run away,thus provided with concealed geotherm ore-forming condition.