北京平原区西北部隐伏岩体的空间分布特征

Spatial distribution characteristics of several plutons in northwest Beijing plain

隐伏岩体的空间形态是地热系统研究的重要内容。利用最新的重力、CSAMT、微动测深和以往的磁法资料研究北京平原区西北部几处隐伏岩体的空间分布,结果表明,花塔岩体、葛村岩体、阳坊岩体和百善东岩体的地球物理特征有所差异,反映了岩体侵入期次的不同及所处构造环境的差异。研究区西南部花塔岩体和葛村岩体之间分布有较厚的第四系和蓟县系白云岩地层,可能是形成地下热水的主要径流通道。阳坊岩体与蓟县系热储层接触形态上呈现西缓东陡的特点。隐伏岩体的分布受南口山前断裂、南口—孙河断裂和影壁山断裂构造的联合控制。

The survey of pluton distribution is vital to the study of geothermal system. Using the latest gravity,CSAMT,microtremor survey and previous magnetic data,the authors studied the spatial distribution of several plutons in northwest Beijing. The results show that these plutons have different geophysical characteristics,which suggests that they were formed in different intrusive periods and were developed in different tectonic environments. There are thick dolomite strata of Quaternary period and Jixian System between Huata pluton and Gecun pluton in the southwest of the study area,which may be the main flow channel of underground hot water. The intrusive occurrence of Yangfang pluton exhibits gentle slope in the west and steep slope in the east. The distribution of these plutons is controlled by Nankou Mountain front fault,Nankou-Sunhe fault and Yingbishan fault.