Method and effect of delineating concealed plutons with airborne gravity and magnetic data in the Qihe thick coverage area of Shandong Province

The Qihe area of Shandong Province is widely covered with thick Cenozoic strata, however it has great potential for the exploration of high-grade iron resources.Delineation of concealed intrusives is of great significance to improve the degree of basic geological research and mineral exploration in the thick overburden area.The accuracy of anomaly interpretation was improved by aeromagnetic gravity and magnetic data processing, and the range of concealed intrusives were delineated by aeromagnetic △T vertical first derivative, normalized total horizontal derivative vertical derivative and airborne gravity residual anomaly.Six intermediate-basic plutons were delineated in the study area.The depths of the concealed plutons' top surfaces are obtained by means of airborne magnetic tangent method, joint inversion of airborne gravity and magnetic profile and the information from ground electrical survey and boreholes.The three-dimension imagines of the top surface of Litun, Pandian and Dazhang plutons were plotted.In the thick overburden area, the application of airborne gravity and magnetism combined with geophysical exploration and drilling to the delineation of concealed plutons provides important information for further geological research, prospecting and drilling.