The formation mechanism of the Cona Woka rift in Eastern Himalaya and its influence on the Tethyan Himalayan polymetallic deposits revealed by magnetotelluric imaging

Abstract

Located in the eastern Himalaya and surrounded by Yalaxiangbo dome, the Cona Woka rift may provide valuable information for the extensional mechanism of crust and distribution of the Tethyan Himalayan polymetallic deposits. Here, for the first time we obtain the three-dimensional electrical structure reaching a depth of approximately 45 km across the Cona Woka rift. Underneath the Cona Woka rift, the electrical model reveals the intersection between the deep electrically conductive body (effective conductivity value of 0.29 s/m, 10–45 km depth) and the shallow conductive layer (conductivity value of 0.3–1 s/m, <10 km depth). We propose that the tearing of Indian slab should have contributed to the partial melting of the crust. The upper and middle crust has a melt fraction of approximately 17–20 vol%, which may deform locally to form the Cona Woka rift. The Yalaxiangbo dome is also influenced by the local deformation of the crust. Moreover, the local deformation may drive the upward migration of the fluids along the rift zone to mix with the shallow meteoric water, especially in the intersection of the Cona Woka rift and the east-west trending faults, affecting the distribution of Tethyan Himalayan polymetallic deposits.