Lithospheric electrical structure of the Great Xing’an Range

Abstract

In order to study the lithospheric structure and survey deep resources perspective of the Great Xing’an Range area, a magnetotelluric sounding profile across the central Great Xing’an Range has been completed. The profile starts from the eastern margin of the Hailaer basin, through the Great Xing’an Range to the western margin of the Songliao basin. An electrical structure model of the crust and the upper mantle was finally obtained after data processing, qualitative analysis and 2D inversion of the observed data. The electrical structure can be divided into three tectonic units: the Hailaer basin, the Great Xing’an Range and the Songliao Basin, which is consistent with the regional geology. The research shows that: (1) The high resistivity in the upper crust of the Great Xing’an Range may represent spatially multiple overlapping volcanic rocks, in addition, the low resistivity bodies in the middle-lower crust may reflect hot and weak materials; (2) The lower crust of the Great Xing’an Range may have experienced delamination; (3) There is a lithospheric scale of west-dipping structural transfer zone between the Great Xing’an Range and the Songliao Basin, inferring that the Songnen Terrane firstly subducted to the Xing’an Terrane, then sutured in the form of soft collision, and finally modified by volcanic activities later.