Silicate-melt inclusions in Recent Vesuvius lavas (A.D. 1631-1944); I, Petrography and microthermometry
Silicate-melt inclusions in Recent Vesuvius lavas (A.D. 1631-1944); I, Petrography and microthermometry (in Proceedings of the Eleventh European symposium on Fluid inclusions research (ECROFI XI), Benedetto De Vivo (editor) and Pierfranco Lattanzi (editor))
European Journal of Mineralogy (October 1992) 4 (5): 1113-1124
Silicate-melt inclusions hosted by clinopyroxene, leucite, olivine and plagioclase phenocrysts have been studied by petrography and microthermometry. Fourteen lavas erupted during the Mt Vesuvius recent activity have been examined. Bubble and inclusion volumes have been measured and the bubbles found to represent 2-7 vol.% (average values) of the inclusions, the range being 0.2-84 vol%. Raman spectroscopic analyses indicate that some bubbles may contain low density CO (sub 2) . Microthermometric experiments were used to homogenize 64 silicate-melt inclusions in clinopyroxene, leucite, and plagioclase. The homogenization T for clinopyroxene and leucite are similar (1150-1265 +- 20 degrees C), whereas that for plagioclase is low (1110-1210 +- 20 degrees C). These data are compatible with a relatively volatile-poor environment during most phenocryst crystallization at depth, though the presence of uncommon, large, gas-rich inclusions indicates occasional volatile- rich conditions.