东北地区火成岩的航磁异常特征分析

Characteristics of aeromagnetic anomalies in igneous rocks in Northeast China

为了解不同时代火成岩的航磁异常特征,对东北地区1∶20万的航磁资料进行了化极、向上延拓及垂向导数的处理。通过与地质图进行对比分析,总结出研究区火成岩的航磁特征:区内广泛分布的各时代花岗岩表现出了不同的磁异常特征,寒武纪、石炭纪、三叠纪等时代的花岗岩表现为高磁异常,而二叠纪及侏罗纪花岗岩表现为低磁异常,其中磁异常最高的岩性为石炭纪花岗岩,磁异常最低的是二叠纪花岗岩。测区内存在的喷出岩-古近纪玄武岩磁异常较高,而更新统玄武岩并未见明显的异常特征。

In order to understand the characteristics of aeromagnetic anomalies of igneous rocks with different ages,various data process approaches such as reduction to the pole,upward continuation and vertical derivative of the 1∶200 000 aeromagnetic data in Northeast China have been carried out.By comparing with the geological maps,it is indicated that the granites widely distributed in the study area,show different magnetic anomaly characteristics,i.e.the Cambrian,Carboniferous and Triassic granites show high magnetic anomaly,but the Permian and Jurassic granites show low magnetic anomaly;the highest magnetic anomaly in the study area is with Carboniferous granite,and the lowest magnetic anomaly is with the Permian granite.The magnetic anomalies of the eruptive rock-Paleogene basalt in the survey area are high,but there are no obvious anomalous characteristics of Pleistocene basalt.