Resistivity pattern of crust and upper mantle in Southern Urals

A resistivity model of the southern Urals to depths of 120 km was obtained by numerical simulation of natural- and controlled-source EM soundings at 160 kHz to 4⋅10−4 Hz. The structure of crust and upper mantle was imaged along a transect running ∼800 km across the East European Platform, the Ural foredeep, and the Ural mountains. The new data on geology and tectonics of the southern Urals enlarge the knowledge gained through URSEIS-95 reflection profiling along one of best representative cross-orogen profiles. We discovered a large conductor traceable to depths at least 100–120 km at the junction between the East European Platform and the Ural foredeep. It indicates that the Ural foredeep originated in a weak tectonic zone at the platform edge. The Ural orogen is imaged as a nearly bivergent structure to depths of 70–80 km producing a mosaic pattern of conductors rooted deep beneath the Magnitogorsk greenstone province and the granitic belt of the central East Ural uplift where it is 150 km wide at a depth of ∼120 km. We interpret the discovered deep roots in the context of the geological history of the Urals.