The Quaternary intraplate volcanoes in Korea have a sparser distribution (~330–563 km) than that of Japanese arc volcanoes (~80 km), geochemistry indicating mixing of components from the stagnant slab and mantle transition zone, and a longer elapsed time (~10–20 Myr) of the Quaternary eruption after the stagnation of the Pacific Plate. Although volcanism can be explained by wet plumes originating from the hydrous layer of the stagnant slab, previous numerical studies could not consistently explain the spatiotemporal and geochemical observations because of the neglected partial hydration of the mantle transition zone and wadsleyite–olivine phase transition at the 410-km discontinuity, both of which affect the viscosity and buoyancy structures. Thus, we constructed a series of two-dimensional numerical models by considering the partial hydration of the mantle transition zone and phase transition at the 410-km discontinuity. The results showed that the wet plumes are retarded at the 410-km discontinuity by the phase transition and merge into batches forming hybrid plumes in the asthenosphere, explaining the mixing of components from the hydrous slab and mantle transition zone, evidenced by the geochemical observations. The spacing (~485 km) and elapsed time (~24 Myr) of the hybrid plumes beneath the lithosphere are consistent with the spatiotemporal observations. Furthermore, the degree of mixing of the components from the hydrous slab and mantle transition zone found in the hybrid plumes explains the spatial distribution of water in the mantle transition zone beneath Korea.
|Publication status||Published - 2022 Aug 20|
Bibliographical noteFunding Information:
We thank Prof. Claire Currie for the editorial effort, and Dr. Guillaume Richard and an anonymous reviewer for the careful and constructive suggestions. This study was supported by the National Research Foundation of Korea (grant numbers 2017R1A6A1A07015374 and 2022R1A2C1004592 ) and Yonsei University Research Fund (grant number 2019-22-0010 ).
© 2022 Elsevier B.V.
All Science Journal Classification (ASJC) codes
- Earth-Surface Processes