Do mantle plumes exist?

The physics of low Reynolds number plumes is well understood, which allows a number of testable predictions to be made about mantle plumes. They are predicted to originate from the core-mantle boundary and consist of a large head followed by a narrower tail. Millions of cubic kilometers of magma can be produced from a plume head. Rifting over a previously-emplaced plume head should produce a narrow zone of thickened oceanic crust along the rift margin. Initial eruption from a plume head should be preceded by ∼1,000 m of domal uplift. Picrites are expected to dominate the first eruptive products of a new plume and should be concentrated near the centre of the volcanic province. All of these predictions are confirmed by observations, and so provide strong support for the validity of the mantle plume hypothesis.