The youth of the ocean floors (0- .3Ma) verses the age of plate tectonics (2-3 Ma) suggests strongly that plate tectonics is cyclic. Densified silicate liquid(Ls) at about 290km depth suggests that it could be the ingredient that lightens the outer core as well as an active ingredient in its activities along with lower mantle phases high density magnesium provoskite (MgPv), calcium perovskite (CaPv), magnesiumwustite (Mw), iron(Ir) and iron liquid(Lm) plus isobarically and isothermally invariant liquid phases. Unstable convective contacts among these phases at all levels produce heat as they...