贵州开阳磷矿西翼矿区地热水成因分析

Geothermal Water Genetic Analysis in Kaiyang Phosphate Mine West Limb,Guizhou

开阳磷矿西翼矿区距息烽温泉仅4 km。从区域地质、水文地质、水化学特征分析了区内地热水的成因,认为区内热储层为震旦系灯影组白云岩,隔热盖层为下寒武统碎屑岩,高丰背斜为储热构造,兴隆断层为传热导水构造。区内地热水是在正常地温梯度的背景下,大气降水由中上寒武统至三叠系地层出露区入渗,经安清断层与震旦系灯影组白云岩含水层相连通而发生深循环,在兴隆断层与隔热盖层的联合作用下,高丰背斜将1 800 m深度内的热量储集起来,使灯影组含水层出现异常地温梯度,从而在灯影组白云岩中形成地热水,热储温度可达65℃以上。

The Kaiyang phosphate mine west limb is away from the Xifeng hot spring only 4 km. From the regional geology,hydrogeology and hydrochemical features aspects have analyzed genesis of geothermal water in the region. The result has considered that the geothermal reservoir is the Sinian Dengying Formation dolomite,heat insulation overburden is lower Cambrian clastic rocks. The Gaofeng anticline is reservoir structure,while the Xinglong fault is heat transferring and water conducting structure. Geothermal water in the region is under a normal geothermal gradient background,atmospheric precipitation infiltrating into strata from middle and upper Cambrian to Triassic outcropped area,via the Anqing fault connected Sinian Dengying Formation dolomite aquifer and formed deep circulation. Under Xinglong fault and heat insulation overburden joint effect,Gaofeng anticline accumulated heat within 1800 m depth,made the Dengying Formation aquifer happened abnormal geothermal gradient. Thereby formed geothermal water in Dengying Formation dolomite,geothermal reservoir temperature can be reached 65℃ above.