Subsidence Amidst Uplift: Lithosphere Delamination During Plume-Lithosphere Interaction

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Abstract
Mantle plumes are commonly believed to generate uplift of their overlying lithosphere, while also impacting climate and life. However, sedimentary deposits show a component of subsidence during plume-lithosphere interaction, challenging traditional uplift-only models of plume-lithosphere interaction. We investigate whether plume-induced delamination can induce subsidence as well as uplift through computations of plume-lithosphere interaction. When a denser lithospheric keel delaminates, initial plume ascent will induce ~2 km of uplift, followed by a more rapid ~2 km of subsidence over a few millions of years as the dense lithospheric keel delaminates. Delamination, distinct from back-arc extension and slab-induced flow, may explain observed subsidence patterns during continental flood basalt activity, such as those seen in the Paraná Flood Basalt, Columbia River Flood Basalt, Deccan Traps and Congo Basin regions.