Construction and destruction of the North China Craton with implications for metallogeny: Magnetotelluric evidence from the Hengshan-Wutai-Fuping region within Trans-North China Orogen

The Hengshan-Wutai-Fuping region within the Trans-North China Orogen is an important corridor that preserves the records of Precambrian evolutionary history and Phanerozoic magmatic and metallogenic events in the North China Craton. Here we present 2-D and 3-D inversion models of magnetotelluric data collected from the Hengshan-Wutai-Fuping region and surrounding regions. Our data reveal nearly horizontal high-conductivity layer at lower crustal and upper mantle depths of similar to 35-45 km beneath the Hengshan and Wutai mountains, providing direct evidence for crust-mantle decoupling and magmatic underplating. In the Mesozoic Yixingzhai gold deposits and Boqiang Cu-Mo-Au deposits, two nearly upright conductors cut through the crust and connect the lower crustal high-conductivity layer suggesting frozen channels of fluids and magmas. A west-dipping slab-shaped conductor within the high-resistivity lithosphere beneath the Wutai Complex appears to be the deep extension of the exposed Longquanguan ductile shear zone. These resistivity anomalies can provide new constraints on the subduction-collision events during Precambrian tectonic evolution of the Trans-North China Orogen as well as on the Phanerozoic tectonic-magmatic and metallogenic events in the Hengshan-Wutai-Fuping region. The west-dipping slab-shaped conductor may indicate a westward oceanic subduction between the Wutai and Fuping Complexes with subsequent collision associated with the formation of the Trans-North China Orogen in the Paleoproterozoic. We interpret the crustal and upper mantle conductors to be part of an interconnected fluid/melt transport channel, which probably played an important role for the Mesozoic tectonic-magmatic and metallogenic events as well as the Cenozoic basaltic volcanism in the Hengshan-Wutai-Fuping region. (C) 2016 International Association for Gondwana Research. Published by Elsevier B. V. All rights reserved.