Fluorine and chlorine behavior in chlorine-rich volcanic rocks from White Island, New Zealand

Extraordinarily high chlorine-bearing volcanic bombs were erupted from White Island volcano on January 25, 1987. The concentrations of fluorine and chlorine were measured in these paralava bombs and their likely parent rocks. The paralavas contain glass with over 1.0 wt.% and up to 1.7% of chlorine. The F/Cl ratios and their relationship with other constituents show that the fluorine and chlorine in the bombs were derived from hydrothermal fluid, most likely concentrated brine in an active Crater Pool.

Plot of water-insoluble chlorine against fluorine in the volcanic ejecta on White Island volcano. Those paralava bombs show extraordinarily high abundances of chlorine. The chlorine and fluorine in the paralava bombs are mainly accreted by the hydrothermal system.Figure optionsDownload as PowerPoint slideHighlights
► Extraordinarily high chlorine-bearing volcanic bombs were erupted from White Island volcano on January 25, 1987.
► Those paralavas contain glass with over 1.0 wt.% and up to 1.7% of chlorine.
► The F/Cl ratios and their relationship with other constituents show that the fluorine and chlorine in the bombs was derived from hydrothermal fluid.