泰安市桥沟地热田水文地球化学特征及其成因分析

Hydrogeochemical Characteristics and the Origin Analysis of Qiaogou Geothermal Field

桥沟地热田地处泰安市徂徕镇桥沟村西,20世纪70年代初被发现,为带状热储型的低温地热资源。笔者通过对该地热田已有钻探和地热地质资料分析,结合本次开展的地热地质调查、地温场调查、水文地球化学测试等工作,探讨地热水的主量元素、微量元素、放射性元素、同位素等组分特征,研究了地热水的补给来源、形成年龄及成因,建立了泰山岩群热储—第四系黏质砂土和寒武纪灰岩盖层—断裂构造型深循环对流通道—大地热流热源的热储概念模型。桥沟地热田地热水以阳离子Na^(+)、Ca^(2+)和阴离子SO^(2-)_(4)、Cl^(-)为主,为SO_(4)·Cl-Na·Ca型。为氟水、偏硅酸水型理疗热矿水,对皮肤病、关节炎等疾病有特殊的医疗作用。地热水主要来自于大气降水,受大陆溶滤水演化影响,以“次现代和最近补给的混合”为主,经计算,形成年龄为20.41~30.21a。通过K-Mg温标和玉髓温标推测深层热储层温度仍有上升空间。地热流体的成因起源事关地热资源利用的可持续发展,希望能够对该地热田地热资源的开发利用提供数据支撑。

Qiaogou geothermal field is located in western Qiaogou village in Culai town of Tai'an city.It was discovered in the early 1970s.It is a banded thermal reservoir type low temperature geothermal resource.By studying and analyzing the existing drilling and geothermal geological data of Qiaogou geothermal field,combining with geothermal geological survey,geothermal field survey and hydrogeochemistry,major elements,trace elements,radioactive elements and isotopic composition characteristics of geothermal water in Qiaogou geothermal field have been stuied,and the source,age and origin of geothermal water have been summarized,the concept model of Taishan rock group heat reservoir—Quaternary clayey sand and Cambrian limestone cap rock—deep circulation convection channel of fault structure and heat source of earth heat flow have been established.In Qiaogou geothermal field,Na^(+)and Ca^(2+)are main cations,SO^(2-)_(4)and Cl^(-) are main anions,and hydrochemical type is SO_(4)·Cl-Na·Ca.Geothermal water is fluorine water and metasilicic acid water,which has special medical effect on skin diseases and arthritis.The geothermal water mainly comes from atmospheric precipitation and is mainly recharged from"sub modern to before 1952"due to the influence of continental leaching water evolution.The age of formation ranges from 20.41 to 30.21 years.The K-Mg temperature scale and the SiO_(2) temperature scale are calculated.It is speculated that the temperature of deep thermal reservoir in Qiaogou geothermal field can still rise.The origin of geothermal fluid is related to sustainable development of geothermal resources utilization.This study will provide data support for the development and utilization of geothermal resources in Qiaogou geothermal field.