The November 2002 eruption of Piton de la Fournaise, Réunion: tracking the pre-eruptive thermal evolution of magma using melt inclusions

摘要: The November 2002 eruption of Piton de la Fournaise in the Indian Ocean was typical activity volcano from 1999 to 2006 terms duration and volume magma ejected. first erupted a basaltic liquid with small proportion olivine phenocrysts (Fo81) that contain numbers melt inclusions. In subsequent flows, crystals were more abundant richer Mg (Fo83–84). These numerous fluid inclusions, healed fractures, dislocation features such as kink bands. major element composition inclusions this later (Fo83–84) is out equilibrium its host result extensive post-entrapment crystallization Fe2+ loss by diffusion during cooling. Melt Fo81 are also chemically their hosts but lesser degree. Using olivine–melt geothermometry, we determined trapped at lower temperature (1,182 ± 1°C) than Fo83–84 (1,199–1,227°C). This methodology used estimate temperatures. inclusion compositions suggest they temperatures between 1,070°C 1,133°C immediately before quenching. relatively wide range may reflect fact most lava samples therefore likely underwent minor variable amounts post-eruptive due slow cooling on surface. contrast, tephra past eruptions yielded narrower higher (1,163–1,181°C). data presented here earlier publications consistent model recharge depth eruptions, followed storage, cooling, shallow levels prior expulsion events similar magnitude eruption.