高阳地热田及邻区地热资源形成机制

临近雄安新区的高阳地热田处于渤海湾盆地冀中坳陷，区内发育以中元古界长城系、蓟县系及下伏的太古界为主的潜山地层，其中蓟县系雾迷山组为地热田主要热储层，地热资源丰富。以岩溶热储顶面埋深3600 m线作为高阳地热田的边界，地热田主体位于高阳低凸起、蠡县斜坡内，并涵盖保定凹陷、饶阳凹陷的少量地区。高阳地热田位于区域岩溶顶板温度较高地区，其中高阳低凸起中北部及其西侧边界、蠡县斜坡与饶阳凹陷交界处为温度最高区域，可达120 ℃左右，地热田南部、中东部属蠡县斜坡区域温度低于100 ℃。潜山热储温度等值线整体呈椭圆形态，长轴为NNE向。蓟县系雾迷山组地热水在博野地区水化学类型为Cl-Na型，溶解性总固体约5 000 mg.L-1，Cl-（约2 300 mg.L-1）含量明显高于雄县、容城等其它地区，SO42-含量（123~133 mg.L-1）高于同属冀中坳陷的雄县、容城、霸州地区，但低于天津地热田和良乡地热田，表明冀中坳陷与天津、良乡地区分属不同的地热系统。高阳地热田形成的概念模式为来自西部太行山地区的大气降水作为地下水的补给水源，太行山前断裂沟通了地表水与深部基岩地层，大气降水在基岩内经衡水断裂、安国断裂、百尺断裂、出岸断裂及不整合面向东侧渤海湾盆内运移，经断层与基岩发生热对流被加热，随着水动力条件减弱，在高阳低凸起、蠡县斜坡、深泽低凸起等区域聚集形成具有勘探开发价值的高阳地热田。 

Genetic mechanism of geothermal resources in the Gaoyang geothermal field and adjacent areas

As a green and renewable energy，geothermal energy plays an important role in solving the haze prob?lem northern China. Gaoyang geothermal field，near the Xiong’an New Area，is rich in geothermal resources. It is located in the Jizhong depression of the Bohai Bay basin，hosts strata of Jixian System andChangcheng System of Mesoproterozoic and Paleoproterozoic，in which the Wumishan Group of Jixian System is the main strata with reservoirs. The buried depth 3,600 m of the top of karst reservoir is considered as the boundary of the thermal field. The main body of the geothermal field is located in Gaoyang sub-uplift and Lixian slope, and covers a small area of the Baoding depression and Shaoyang depression. The Gaoyang geothermal field lies in an area of the karst reservoirs top surface with high temperature，where the temperatures of the middle and northern part of Gaoyang sub-uplift，the western boundary，and the junction area of Lixian slope and Shaoyang depression reach 120 ℃, while that of southern part of the geothermal field and the middle and eastern part of the Lixian slope is lower than 100 ℃. Overall the temperature contours of buried hill geothermal reservoirs exhibit an elliptic shape with a long axis in NNE direction. In hydrochemistry, geothermal water of Wumishan Group of Jixian System in the Boye area is of Cl-Na type，with solubility about 5,000 mg?L-1 and content of Cl-（2，300 mg?L-1） that is obviously higher than Xiongxian，Rong Cheng and other areas，while the solubility of SO42-（123-133 mg?L-1）is higher than Xiongxian，Rongcheng and Bazhou，and lower than the Tianjin and Liangxiang geothermal fields. This shows that the Jizhong depression belongs to a different geothermal system with the Tianjin and Liangxiang areas. The conceptual model of the Gaoyang geothermal field suggests that the atmospheric precipitation of the Taihang Mountains to the west is the supply of groundwater and the piedmont faults of the Taihang Mountains connect the surface water with reservoirs. Atmospheric precipitation flows through piedmont faults，the Hengshui fault，Anguo fault，Baichi fault，Chu’an fault and unconformities，and migrates to the Gaoyang sub-uplift，Lixian slope and Shenze sub-uplift where traps form. The fluid is heated by heat convection during the process of flowing through faults and bedrocks，forming the Gaoyang geothermal field which has a great potential of exploration and exploitation.