| 基于重磁异常的北京副中心地质构造特征和地热控制作用研究 |
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| 引用本文：雷晓东,赵玉,唐显春,王立发,何付兵,关伟,李娟.2023.基于重磁异常的北京副中心地质构造特征和地热控制作用研究[J].地球学报,44(1):79-92. |
| DOI：10.3975/cagsb.2022.092601 |
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| 基金项目:中国地质调查局地质调查项目(编号: 12120114033901; DD20160229);北京市地质矿产勘查开发局市级财政项目(编号: PXM2016_158307_000013; PXM2017_158307_000008);国家自然科学基金项目(编号: 41877197) |
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| 中文摘要:重磁勘探对于分析地热系统特征和成因十分重要。北京城市副中心当前地热开发程度较低, 为给地热资源可持续利用提供依据, 对近期完成的1:50 000高精度区域重力测量资料, 开展了场源边缘检测、 2.5D剖面反演和三维反演计算。利用归一化Theta图垂向导数和一阶水平方向导数获得了精度更高的断裂位置, 研究了断裂汇交特征; 使用频率域Parker-Oldenburg方法反演获得了两条不同方向剖面的基岩起伏形态; 使用信赖域反演算法获得了5 km以浅地层三维视密度异常特征。在此基础上结合1:100 000航磁和钻孔资料分析, 综合研究了副中心地质构造特征及其地热控制作用, 得到结论如下: (1)研究区断裂构造以近NE向和NW向为主。NE向断裂延伸较远、梯度带宽, 但被NW向断裂切割改造迹象明显。(2)太古界结晶基底差异性隆升使区内储层和盖层厚度变化大。研究区南部隆起区蓟县系储层厚度变薄或缺失。新生界盖层在隆起区厚度为200~800 m, 在断陷盆地区达2000 m以上。(3)南苑—通县断裂和夏垫断裂是区内良好导热构造; NW向台湖断裂、张家湾断裂与NE向燕郊断裂、姚辛庄断裂是主要导水通道, 与南苑—通县断裂和夏垫断裂交汇形成区内地热资源的主要补给径流通道。区内地热异常受不同级次构造控制在赋存特征上呈现较大差异。 |
| 中文关键词:重力异常 地热 重磁反演 Theta图 北京副中心 |
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| Gravity and Magnetic Study of Structure and Associated Geothermal System in Beijing Sub-center |
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| Abstract:Gravity and magnetic exploration is very important for analyzing the characteristics and genesis of geothermal system. At present, the geothermal development of Beijing’s sub center is still not enough. In order to provide a geophysical basis for sustainable utilization of geothermal resources, the edge detecting of the potential fields, 2.5D profile inversion and 3D inversion calculation were carried out for the latest 1: 50 000 high-resolution regional gravity survey data. Using the normalized Theta diagram vertical derivative and the first order horizontal derivative, we obtained the fault location with higher accuracy and studied its intersection characteristics. Using Parker-Oldenburg method in frequency domain, the bedrock burial conditions of two profiles in different directions was obtained by 2.5D inversion. Using the trust region inversion algorithm, the apparent density anomaly characteristics of strata less than 5 km in depth was obtained by 3D inversion. On this basis, combined with 1:100 000 aeromagnetic and borehole data analysis, the geological structure characteristics and geothermal control of the sub-center were comprehensively studied. The conclusions are as follows: (1) the faults in the study area are mainly NE–trending and NW-trending. The NE–trending faults have strong continuity and wide gradient zone of gravity anomaly, but are reconstructed obviously by NW–trending faults. (2) The differential uplift of Archaean crystalline basement makes great changes in the thickness of geothermal reservoir and cap rock in the study area. The thickness of Jixian system reservoir in the southern uplift becomes thinner or missing. The thickness of Cenozoic cap rock is 200~800 m in uplift area and more than 2000 m in fault basin area. (3) Nanyuan–Tongxian fault and Xiadian fault are excellent heat control and water transfer channels in the study area. The NW-trending faults including Taihu fault, Zhangjiawan fault, and NE-trending faults including Yanjiao fault and Yaoxinzhuang fault are also the main water diversion channels in the study area. They intersect with Nanyuan–Tongxian fault and Xiadian fault to form three main runoff channels. There are great differences in oc-currence characteristics of geothermal anomalies controlled by different structures. |
| keywords:gravity anomaly geothermal gravity and magnetic inversion Theta map Beijing sub-center |
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