四川屏山灯盏窝温泉地球化学特征及成因

HYDROCHEMISTRY AND ORIGIN OF HOT SPRING IN DENGZANWO-PINGSHAN SICHUAN

对屏山灯盏窝地热水和地下水的化学和同位素分析表明:灯盏窝地热井揭露的两个热储层,三叠系雷口坡组热储埋深623~1 111m,水温39.4℃,TDS含量为15 800mg/l,水化学类型为Cl·SO4-Na型;二叠系栖霞茅口组热储埋深2 040~2 618m,水温78.3℃,TDS含量为450mg/l,水化学类型HCO_3^--Cl·Ca-Na型。雷口坡地热水的δD为-47.5‰,δ^(18)O为-7.7‰,是大气降水与沉积水混合形成;栖霞茅口组热水δD为-64.8‰,δ^(18)O为-10.9‰,来源于大气降水。热水与地下冷水水化学、同位素组成有较大差异,说明经历了比冷水更长的循环深度和不同的成因,深部热水的补给与附近泉水、地表水和金沙江水关系不大,灯盏窝热水发育受五角堡-楼东背斜核、糖房湾穹隆构造控制,该区地热水具有较高的开采利用潜力。

The results of chemical and isotopic analysis of geothermal water and groundwa- ter in Dengzanwo pingshan are indicated： two hot reservoirs have been exposed by the geothermal well The thermal reservoirs in Middle Triassic Leikoupo Fm buried depth 623 1 111 m,water temperature was 39.4℃, content of TDS was 15 800 mg/l, hydrochemical type was Cl·SO4-Na. The thermal reservoirs in the Permian Qixia-Maokou Group buried depth 2 040-2 618 m, water temperature was 78.3 ℃ o The value of δD Leikoupo Group geothermal water was -47.5%0 and δ^18O was -7.7%0. It was a mixture of precipitation and sedimentary water. δD and δ^18O values of Qixia-Maokou Group geothermal water -64.8%0 and -10.9%0 ,and it is from the precipitation. There are significant differences between hot water and underground cold water in chemistry and isotope composition, which shows that geothermal water had experienced a longer circulation depth and different causes than cold groundwater. Supply of the geothermal water has little connection with nearby springs, surface water and jinsha river water. Geothermal water of Dengzanwo is controlled by anticline core of Wujiaobao-Loudong and dome structure of Tangfangwan. The geothermal water in this area has high utilization potential.