摘要
鲜水河断裂是中国地震活动最为频繁的深大断裂之一,磨西断裂为其南延段,区内水热活动强烈,地壳活动信息蕴藏干水热活动之中。本文沿着磨西断裂(康定→磨西→湾东→石棉)采集活动带内典型热水,对其水文地球化学特征进行分析:通过Na-K-Mg平衡图解,结合水的电离、矿物稳定的温度效应解释热水水岩平衡状态;采用传统地热温标法结合热水焓、氯关系对热水冷却途径、混合特征进行分析。研究亦引入热水短周期信息固体潮响应特征分析,并构建此断裂带水热活动地热地质空间模型。研究认为康定灌顶为水热系统中心,向南水热活动减弱,边界位于石棉草科附近;热水被深部热源加热,喜山期花岗岩为主热储层;南面温泉普遍具有被二叠系结晶灰岩作为次热储层中的热水混合的特征。研究是对磨西断裂水热活动系统研究的深化,也是新方法的探索。其中热水短周期信获取容易,监测灵活,是未来研究深部地质环境信息研究的关键技术之一。
The Xianshuihe fault with frequent earthquakes activities is the regional deep fault in China.The Moxi fault is located in the southern extension of the Xianshuihe fault where the intensive hydro-thermal activities implying abundant information of deep crust.In this contribution,the hydro-geochemistry of the typical thermal springs were examined along the Moxi fault(direction as the Kangding→Moxi→Wandong→Shimian).The state of water-rock equilibrium are explained by the Na-K-Mg equilibrium diagram together with the ionization of water and stable temperatures of minerals.Traditional geothermometers,combined with the relationship between the enthalpy and chlorine of thermal water,are used to analyze the cooling approaches and the mixture of thermal water.Moreover,the responses to the short cyclic solid tide are constrained for proposing the geological space model of the hydrothermal activities of the fault.The Guanding in Kangding and Shimian in Caoke are considered as the center and margin of the hydro-thermal system,respectively,which perform the southward decrease of hydrothermal activities.Thermal water are heated by the deep heat source of the Himalayan granites(the main heat reservoir),while the thermal springs in the south perform the mixture of thermal water in the sub-reservoir of the Permian crystalline limestones.The research for the system of hydrothermal activities in the Moxi fault are deepen and explored as a new method.Meanwhile,the cyclic information of thermal water,achieved conveniently and observed flexibly,is the key for solving the geological data from the deep earth.