延庆盆地大地热流异常及其构造背景  

Genesis of the heat flow anomaly in Yanqing basin,NW Beijing

作　　者：雷晓东 李晨 王立发 赵玉 尤志鑫 唐显春 关伟 李娟 LEI XiaoDong;LI Chen;WANG LiFa;ZHAO Yu;YOU ZhiXin;TANG XianChun;GUAN Wei;LI Juan(Beijing Institute of Ecological Geology,Beijing 100120,China;Sinoprobe Center,Chinese Academy of Geological Sciences,Beijing 100037,China;Beijing Institute of Geothermal Research,Beijing 102218,China)

机构地区：[1]北京市生态地质研究所,北京100120 [2]地球深部探测中心,中国地质科学院,北京100037 [3]北京市地热调查研究所,北京102218

出　　处：《地球物理学报》2022年第9期3405-3418,共14页Chinese Journal of Geophysics

基　　金：北京市地质矿产勘查开发局项目(PXM2019_158203_000003);北京市规划和国土资源管理委员会延庆西北部发展区地热资源勘查与评价(一期)项目;北京市市级职工创新工作室(环境与资源地球物理探测)项目联合资助.

摘　　要：基底构造探测对地热成因机理研究十分重要.对近期完成的区域重力测量数据开展了场源边缘检测和密度界面反演等处理,获得了延庆盆地新生界基底形态及断裂展布特征.同时收集钻孔测温和热导率资料计算了17眼钻孔的大地热流,分析了热流异常及其构造成因,得到结论如下:(1)延庆盆地的基底形态为“一凸四凹一单斜”,即东五里营凸起、姚家营凹陷、张老营凹陷、田宋营凹陷、卓家营凹陷、康庄—沈家营单斜带.延庆盆地由2条NE向断裂控制,6条近SN向断裂连通山区补给区并切割NE向断裂,构成纵横交错的浅部断层网络.(2)延庆盆地大地热流平均值为65.8±13.0 mW·m^(-2),略低于渤海湾盆地热流均值,相对高热流区有两处,一是康庄—沈家营断裂和靳家堡断裂交汇区,二是西卓家营凹陷和东五里营凸起之间的过渡带.(3)延庆盆地地表热流异常主要与蓟县系碳酸盐岩高热导率地层分布及其厚度变化、多体系浅部断裂组合控制地下水热活动促使热流再分配有关,盆地北缘佛峪口—黄柏寺断裂发育和燕山期花岗岩侵入影响较小.Geophysical survey of basal structure is important for providing information that can help us to understand the genesis of heat flow anomaly.Using data from the recently completed regional gravity survey,the field source edge detection and density interface inversion are used to obtain the Cenozoic basement morphology and fault distribution characteristics in Yanqing basin.Meanwhile,we calculate the heat flow of 17 boreholes from its temperature logging data and the regional thermal conductivity measurement data,then analyze the tectonic setting of heat flow anomaly.The result reveals that(1)The basement relief of Yanqing basin can be divided into"one uplift,four sags and one monoclinic",including Dongwuliying uplift,Yaojiaying sag,Zhanglaoying sag,Tiansongying sag,Zhuojiaying sag and Kangzhuang-Shenjiaying monoclinic.The Yanqing basin is mainly developed by two NE-trending faults,and six nearly SN-trending faults which connect with the recharge area of south and north mountains and cut NE-trending faults,forming a crisscross shallow fault network.(2)The average value of heat flow in Yanqing basin is 65.8±13.0 mW·m^(-2),which is slightly lower than that of Bohai Bay basin.There are two abnormal areas of high heat flow,one is the convergence area of Kangzhuang-Shenjiaying fault and Jinjiapu fault,the other is the transition zone between the Xizhuojiaying sag and the Dongwuliying uplift.(3)The heat flow anomaly in Yanqing basin is mainly related to the distribution and thickness variation of the Jixian carbonates with high thermal conductivity and the heat flow redistribution promoted by groundwater thermal activity which is controlled by multi-system shallow faults,while it has little relationship with the development of Foyukou-Huangbaisi fault and the intrusion of Yanshanian granite.

关 键 词：重力异常 大地热流 基底构造 断裂 延庆盆地 

分 类 号：P314[天文地球—固体地球物理学]