Silicate-melt inclusions in recent Vesuvius lavas (A.D. 1631–1944): I. Petrography and microthermometry
Vaggelli, Gloria; Belkin, Harvey E.; De Vivo, Benedetto; Trigila, Raffaello
European Journal of Mineralogy Volume 4 Number 5 (1992), p. 1113 - 1124
published: Oct 14, 1992
manuscript accepted: Dec 9, 1991
manuscript received: Jun 27, 1991
ArtNo. ESP147050405024, Price: 29.00 €
Abstract 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 (southern Italy) recent activity (A.D. 1631-1944) have been examined. Bubble and inclusion volumes have been measured and the bubble represents from 2 to 7 vol.% (average values) of the inclusion; the minimum and maximum values range from 0.2 to 84 vol.%. Raman spectroscopic analyses indicate that some bubbles may contain low density CO2. Microthermometric experiments with a LEITZ 1350 heating stage were used to homogenize 64 silicate-melt inclusions in clinopyroxene, leucite, and plagioclase. The homogenization temperatures for clinopyroxene and leucite are similar and range from 1150 to 1265 °C (± 20°); whereas, the homogenization temperature measured in plagioclase is lower (1110 and 1210 °C [± 20°]). These data are compatible with a relatively volatile-poor environment during most phenocryst crystallization at depth; however, the presence of uncommon, large, gas-rich inclusions indicates volatilerich conditions during some episodes of phenocryst crystallization.