Do deep mantle plumes feed volcanic hotspots such as Hawaii, or do shallower plate processes explain them?
Since its introduction the plume hypothesis has been repeatedly adapted to fit observed hotspots rather than making firm predictions, and critics have developed a rival plate hypothesis; with the growing number of models the plume concept has been criticized as a weakly defined hypothesis that as a general term is currently neither provable nor refutable. Seismic tomography has produced evidence read as favoring a plume beneath Hawaii and, since 2011, beneath Yellowstone, but the general question stays contested.
What would resolve this Seismic imaging of plume conduits from the core-mantle boundary to the surface at multiple hotspots, with resolution good enough that plume and plate explanations make distinguishably different predictions.
Geophysics, SeismologyMantle Plume (Wikipedia)
Do Deep Mantle Plumes Explain Hotspot Volcanism, or Is the Plate Hypothesis Right?
Whether anomalous volcanic hotspots such as Hawaii and Yellowstone are fed by narrow plumes rising from the core-mantle boundary, or are instead explained by shallow, plate-tectonic-driven processes, is contested as the Great Plume Debate; critics led by Don Anderson, Gillian Foulger and Warren Hamilton argue the plume hypothesis has not reliably predicted new hotspots since its 1971 introduction, while the rival plate hypothesis attributes the same volcanism to near-surface plate processes rather than a deep-mantle source.
What would resolve this Direct seismic tomographic imaging that resolves a continuous, narrow, deep-sourced conduit beneath a disputed hotspot, or a plume-model prediction of a previously unknown hotspot later confirmed by observation, would settle the debate in the plume hypothesis's favor; a demonstrated shallow, plate-driven mechanism sufficient to explain the same hotspots without invoking a deep source would settle it the other way.
GeophysicsMantle Plume (Wikipedia)