Intra-grain Sr isotope evidence for crystal recycling and multiple magma reservoirs in the recent activity of Stromboli Volcano, Southern Italy

Over the last several hundred years, Stromboli has been characterized by steady-state Strombolian activity. The volcanic products are dom-inated by degassed and highly porphyritic (HP-magma) black scoria bombs, lapilli and lava flows of basaltic shoshonitic composition. Periodically (about one to three events per year), more energetic explosive eruptions also eject light coloured volatile-rich pumices with low phenocryst content (LP-magma) that have more mafic composi-tions than the HP-magma. An in situ major and trace element and Sr isotope microanalysis study is presented on four samples chosen to characterize the different modes of activity at Stromboli: a lava flow (1985–1986 effusive event), a scoria bomb from the ‘normal’ present-day activity of Stromboli (April 1984), and a scoria and coeval pumice sample from a recent more explosive eruption (September 1996). Plagioclase (An62–90) and clinopyroxene (Mg-number between 069 and 091) phenocrysts in all samples recor