Fractionation of metals in volcanic emissions

The enrichment of some metals (Al, Mg, Na, K, Cu, Zn, Cd) in volcanic gases is measured by an emanation coefficient, ex, relating the amount of the element x in lavas and in aerosol. Concerning the most volatile species, it appears that practically all the volcanic aerosol are produced by evaporation followed by gas-to-particle conversion and the spattered fraction appears to be negligible