重磁对应分析在火山岩覆盖盆地识别沉积凹陷的应用--以大杨树盆地为例  

Application of gravity and magnetic correspondence analysis in identifying sedimentary depressions of the volcanic rock covered basins-A case study of Dayangshu basin

作　　者：陈亮 杨亚斌[2] 徐梦龙 孙诚业 CHEN Liang;YANG Yabing;XUN Menglong;SUN Chengye(The Institute of Geophysical and Geochemical Exploration,Langfang 065000,China;Modern Geological Exploration Technology Research Center,Langfang 065000,China)

机构地区：[1]中国地质调查局地球物理中心,廊坊065000 [2]中国地质科学院地球物理地球化学勘查研究所,廊坊065000

出　　处：《物探化探计算技术》2022年第4期490-499,共10页Computing Techniques For Geophysical and Geochemical Exploration

基　　金：地质调查项目(DD20211546,DD20190032)。

摘　　要：当盆地盖层和基底存在较大的密度差异时,利用重力异常分离技术获取的重力异常能够有效反应基底的起伏特征,但在火山岩覆盖区的隐伏盆地探测应用中,由于盖层中往往发育高密度火山岩,其重力异常叠加在基底的重力异常之上,很难直接进行异常的分离,需去除火山岩的影响才能取得较好的效果。这里选择大兴安岭东缘地表覆盖火山岩层的大杨树盆地,通过火山岩在盆地内的重磁异常特征分析,提出求取火山岩的磁异常换算为磁源重力异常,再对火山岩的磁源重力异常进行剥离,获取更彻底的基底起伏所引起的重力异常。实际数据处理结果表明,该方法对火山岩盆地沉积凹陷有较好的识别能力。The density difference between the cover and the basement of the basin covered by volcanic rocks is usually large.The residual gravity anomaly of the sedimentary strata obtained by gravity anomaly separation technology can effectively reflect the fluctuation characteristics of the basement.However,in the basin covered by volcanic rocks,it is necessary to remove the influence of high-density volcanic rocks to achieve better results.Based on the analysis of the characteristics of the gravity and magnetic anomalies of the volcanic rocks in the basin,we propose that the residual magnetic anomalies of the volcanic rocks should be converted into the magnetic source gravity anomalies,and then the magnetic source gravity anomalies of the volcanic rocks should be stripped to obtain the more thorough gravity anomalies caused by the fluctuation of the basement.The data processing in the middle and north of Dayangshu basin show that this method has a good recognition ability for the sedimentary depression of volcanic basin.

关 键 词：磁源重力异常 沉积凹陷 火山岩覆盖 大杨树盆地 

分 类 号：P631.4[天文地球—地质矿产勘探]