A hybrid mechanism for enhanced core-mantle boundary chemical interaction
• Kang Wei Lim,
• Irene Bonati,
• John William Hernlund
Kang Wei Lim
Tokyo Institute of Technology

Corresponding Author:kangwei.lim@elsi.jp

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Irene Bonati
Tokyo Institute of Technology
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John William Hernlund
Tokyo Institute of Technology
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## Abstract

Detection of chemical signatures from the core-mantle boundary (CMB) could provide an unprecedented glimpse into our planet’s deep interior and ancient past. Several isotopic and elemental anomalies in ocean island basalts (OIBs) have been proposed as core tracers. However, the process(es) by which particular chemical signatures from the core are conveyed into the mantle remain uncertain. Here we propose a hybrid mechanism that results from a collaborative feedback between dynamic topography, porous infiltration of liquid metal into submerged rock, gravitational collapse of weakened metal-silicate mush, and draw-down of additional rocks from above in the induced small-scale mantle circulation. Using a mantle convection model coupled to gravitational spreading of a thin layer, we show that this mechanism achieves parity with metal-mush interaction alone when the layer is $\sim$10$^5$ times less viscous than overlying mantle.
16 Dec 2021Published in Geophysical Research Letters volume 48 issue 23. 10.1029/2021GL094456