Latest reply on RC2

Abstract

Mid-ocean ridges and mantle plumes are two attractive windows to allow us to get a glimpse of mantle structure and dynamics. Dynamical interaction between ridge and plume processes have been widely proposed and studied, particularly in terms of ridge suction. However, the effects of plate drag on plumes and plume-ridge interaction remains poorly understood. Quantification of suction versus plate drag between ridges and plumes remains absent. Here we use 2D thermomechanical numerical models to study the plume-ridge interaction, exploring the effects of (i) the spreading rate of ridge, (ii) the plume radius, and (iii) the plume-ridge distance systematically. Our numerical experiments suggest two different geodynamic regimes: (1) plume motion prone to ridge suction is favored by strong buoyant mantle plume and short plume-ridge distance, and (2) plume migration driven by plate drag is promoted by fast-ridge spreading rate. Our results highlight fast-spreading ridges exert strong plate dragging force, rather than suction on plume motion, which sheds new light on the natural observations of plume absence along the fast-spreading ridges, such as the East Pacific Rises.