Mantle transition zone structure beneath northeast China with receiver function 3-D kirchhoff migration method

The structure of Mantle Transition Zone (MTZ) in northeast China is of great significance for studying the deep origins of cenozoic intraplate volcanoes and plate subduction. In this paper, more than 60,000 receiving functions in northeast China are collected, and Receiver Function 3-D Kirchhoff Migration method is used to obtain the topography of the MTZ discontinuities and the MTZ thickness variation in northeast China. Results show that both 410-km and 660-km present depress underneath Changbaishan Volcano, while the depress of 660-km is more obvious, reaching more than 25 km, which may be related to the stagnation of the Pacific subduction plate in the transition zone. The MTZ thickness shows a slight thinning on the west of Changbaishan Volcano and Longgang Volcano, indicating that the subduction plate tears near 660 km. The upwelling of hot material caused by plate tearing and subduction plate dehydration together provide the heat source for Changbaishan Volcano. Below the Wudalianchi volcano, the phenomenon of 410-km uplift while 660-km sinking is observed. Combined with the previous research, we believe that the 410-km uplift is related to the delimitation of the lithosphere, and the local convection caused by the delimitation may be the heat source for Wudalianchi Volcano, while the sinking of the 660-km may be caused by the residual subduction plate.