Experimental and modeled solubilities of chlorine in aluminosilicate melts, consequences of magma evolution, and implications for exsolution of hydrous chloride melt at Mt. Somma-Vesuvius

Abstract

Solubility experiments were conducted with forty-one aluminosilicate rock compositions to determine how extensively Cl dissolves in hydrous chloride melt- ± vapor-saturated silicate melts containing low to moderate water contents at 2000 bars. Chlorine solubility in most silicate melts is dominated by the abundances of Mg ≈ Ca > Fe > Na > K > network-forming Al > Li ≈ Rb ≈ Cs, but Ti, F, and P also have strong influences. The relationship of composition to Cl solubility is more complex in peraluminous and peralkaline felsic melts, because network-modifying Al, Na, and K have a greater influence than their network-forming counterparts. Also, the effects of Ca, Mg, and Al in mafic melts characterized by high (Ca + Mg + Al)/(Na + K + Li) are much greater than their effects in silica-enriched melts.