Application Research Of Geology, Geophysics And Geochemistry For Aeromagnetic Anomaly Investigation In Wulatezhongqi, Inner Mongolia

Abstract:Wulatezhongqi, Inner Mongolia located in Lanshang-Zhaertaishan rifting system which belongs to the middle segment of north margin of the North China Platform, is an important deposit-concentrated area of the passive continental margins under the Mesoproterozoic extensional tectonic regime. Based on the regional geological background, the paper has comprehensively studied with the geology, geophysics and the result of drilling in the abnormal area of Enge’ergacha and Baogedagacha. Also the regularity and the genesis of aeromagnetic anomaly and have been discussed respectively. Finally, the potential for prospecting has been analyzed.The regional aeromagnetic anomaly and the anomaly on gravity indicate that the fine-grained diorite in the Permian, fine-grained granodiorite and quartz diorite in the Carboniferous are the main cause of anomaly on aeromagnetic.By ways of geological survey and sample collection, and combined with the rock and mineral identification, this paper preliminary think that the Enge’ergacha anomalies is caused by weak magnetic in the Permian diorite and the weak magnetic Permian granites, while Baogedagacha anomalies is caused by the Cretaceous basalt.Research on the ground high-precision magnetic method and the IP intermediate gradient in the abnormal areas show that the smooth lower abnormal on magnetic field exists in the south and northwest of Enge’ergacha and anode and cathode with great fluctuating in banded abnormal in central and the source of anomaly maybe exist in the deep ground. And the Baogedagacha’s magnetic field have characteristic of a smooth lower abnormal in the north, southeast and southwest and a anode and cathode with great fluctuating in banded abnormal in the northeast, southwest and northwest. And the anomaly is identified as the shallow occurrence. In addition, the IP intermediate gradients have no obvious features of reflecting the aeromagnetic anomaly and have no significant characteristics with lower resistivity and higher polarization of the mineralization.Based on the results of drilling verification and combined with testing data analysis, the content distribution of ore-forming element Fe, Ti is the cretaceous basalt, the Permian diorite and the Permian granite from more to less, and the content was positively related to the intensity of the rock magnetic; The drill core rock geochemical characteristics show that the siderophile elements like Mo, Ni and Co and the chalcophile elements like Cu, Pb, Zn, Au and Ag are respectively embodies the good characteristics of correlation and composition.The contrastive analysis on the geology, geophysics, and geochemistry shows that all these information has the feature with great superposition and coherency, and the local enrichment of the siderophile elements in the rock is the main cause of magnetic anomaly, the analysis indicates that ore prospecting potential in the aeromagnetic anomaly is not optimistic.