Entrainment processes during plume ascent
The entrainment processes of a rising mantle plume are investigated using high-resolution numerical modelling and analogue laboratory experiments. It is found that the ascending plume is enveloped in a plume sheath that effectively blocks entrainment into the plume core region, indicating that the chemical heterogeneity of plumes is predominantly inherited at the plume source region. Distinct spatial regions within the deep plume source region are preserved as distinct vertical stripes within the plume core. Interaction between the rising plume and sharp viscosity interfaces in the mantle can result in massive distortion and deformation of the plume head as well as the stripping off of the protective plume sheath, leading to a remarkably complex compositional structure of the plume and to increased sampling of specific regions in the mantle through entrainment.