Aeromagnetic Anomaly Analysis of Ordos and Adjacent Regions and Its Tectonic Implications

Abstract

AbstractAffiliated to the North China Craton (NCC), the Ordos massif contacts with the Qinling‐Qilian orogenic belt to the south, with complicated geological features around as a result of episodic tectonics. By applying the upward continuation, different order vertical derivative conversions and new edge‐detecting method to aeromagnetic data and combining with earthquake data, here we present the characteristics of aeromagnetic anomalies of field sources at different depths and their tectonic implications. Our results show that the basement of Ordos is rigid on the whole but is still heterogeneous. The east of the Ordos massif in NCC is a relatively weak zone trending approximately NS suffered from subsequent tectonic alteration. The ductile lower crustal material flows along two weak zones of the Qinling and Qilian orogenic belt coevally with the thickening and shortening of the crust in the Tibet Plateau, as well as the anticlockwise rotation of the Ordos massif due to the intensive compressional stress derived from the India‐Eurasia collision in NE direction. The diverse tectonic features mentioned above in and along the margins of the Ordos massif represent the tectonic responses of the crustal blocks of different rigidity to the boundary forces, that resulted in prominent geological features. The tectonic deformation in and around the Ordos massif is characterized by inheritance and superimposition.