Long‐period magnetotelluric (MT) data from project SINOPROBE were acquired and modeled, using three‐dimensional (3D) MT inversion, to study the electrical structure of Ordos Block, a component of the North China Craton. For the first time, a high‐resolution 3D resistivity model of the lithosphere is defined for the region. Contrary to what would be expected for a stable cratonic block, a prominent lithospheric conductive complex is revealed extending from the upper mantle to the mid‐to‐lower crust beneath the northern part of Ordos. Correlating well with results of seismic studies, the evidence from our independent magnetotelluric data supports regional modification of the lithosphere under the north Ordos and lithosphere thinning beneath Hetao Graben. The abnormally conductive structure may result from upwelling of mantle material in mid‐to‐late Mesozoic beneath the northern margin of the Ordos block.

The ongoing India‐Asia collision since the Paleogene created the Tibetan Plateau, the most prominent elevated plateau on our planet. This convergence also contributed to the formation of two distinct types of active surface deformation of the plateau, namely, north–south trending normal fault systems and “conjugate” strike‐slip fault systems. The tectonics and geodynamic mechanism(s) behind this curious combination are still unclear, despite numerous theories proposed over past decades. Here we present a new three‐dimensional, lithospheric‐scale, electrical conductivity model with unprecedented resolution of the central part of Tibetan Plateau derived from the SINOPROBE magnetotelluric array data set and discuss its inferences related to this question. Our model reveals contrasting conductivity structures corresponding to the surface deformation patterns, namely, highly conductive lower crustal anomalies beneath the graben systems in the Lhasa and Qiangtang terranes and moderately resistive crustal features in the strike‐slip region near Bangong‐Nujiang Suture Zone. With the help of experimentally calibrated constraints between conductivity and melt fraction, the conductivity model and the inferred lateral viscosity distribution together suggest a weak lower crust beneath the graben regions, compared to a stronger crustal rheology associated with the strike‐slip zone. Here we expand the previously proposed “extensional extrusion” tectonic model in central Tibet to interpret our conductivity model and other geophysical/geodesic observations. The weak rheology under a N‐S directed primary stress may have caused the east–west extension of the graben regions, which further aides the eastward extrusion of the conjugate strike‐slip zone and eventually shapes the surface deformation of central Tibetan Plateau into its current, complex pattern.