We have conducted laboratory experiments on a laminar thermo-chemical plume generated from a thermal boundary layer which is stratified in composition in order to understand mantle plume dynamics. Temperature (TLCs), composition (LIF), and velocity fields (PIV) are simultaneously visualized for quantitative analysis of the flow behavior of thermo-chemical plumes. Because all plumes cool by thermal diffusion as they rise, a chemically composite thermal plume will eventually attain a level of neutral buoyancy, at which it will begin to collapse. Separation within the plume will occur, whereby the chemically denser material will start to sink back while the heated surrounding material keeps rising. We will discuss the behavior of thermo-chemical plumes in the mantle based on its fluid dynamic scaling.