9419525 Hauri The PI will utilize a thermochromatic liquid crystal-sheet lighting technique to measure the entrainment of ambient fluid into thermally buoyant plume structures under a variety of experimental conditions. The flux of the entrained fluid will be compared to that of the injected fluid to calculate absolute and fractional entrainment. In this way, entrainment into steady state conduits, thermal conduit solitary waves, and time dependent conduit flow will be measured and characterized. The PI will also vary the chemistry of the fluids to investigate the effects of different rheologies on entrainment, which can be tested by examining entrainment in a plume conduit which traverses layers of different density and viscosity. This research has the potential to evaluate mantle plumes as "sampling probes" of the mantle through which they pass, and when combined with existing and future geochemical data, results form seismic tomography, and experimental and theoretical determinations of deep mantle rheologies, will allow the PI to place firmer constraints on the locations of geochemically distinct reservoirs in the convecting mantle ***
