LAUSR

Abstract Textural evidence from occurrences of mingled magmas in lava flows often yields insights into chemical and thermal disequilibrium between multiple magma batches at depth. An understanding of these interactions is key as they can occur on short timescales and may act as eruption triggers, particularly important in very active volcanic settings. This paper focuses on the Pietre Cotte lava flow (Vulcano, Aeolian Islands, Italy), a short ( Petrographic observations and mineral, bulk rock and glass geochemistry suggest that multiple mingling events occurred during the evolution of the Pietre Cotte magmatic system, evidenced by the recognition of the following components: (1) a remobilised predominantly mafic crystal mush, evident as macrocrysts (crystals >500 μm), which form glomerocrysts within enclaves, (2) a microlitic ( Compositionally and texturally distinct magmas are attributed to storage and interactions of distinct magma batches and their cumulates at various temperatures and depths beneath the Fossa Cone. Compositions vary from basaltic-shoshonitic, through latitic-trachytic and rhyolitic magmas. The macrocrystic glomerocryst assemblage shows resorbed, chemically-zoned and cumulate textures; the glomerocrysts are attributed to a shoshonitic parent and remobilisation from a crystal mush. Macrocrysts formed at a pressure of 825 ± 80 MPa and temperatures of 789–1117 °C at around the Moho (~23–28 km). Pressure and temperature calculations of the shoshonitic mineral assemblage give average crystallisation conditions of 710 ± 80 MPa (above the Moho) and 1128 ± 25 °C, respectively. The trachytic magma crystallised at ~640 ± 75 MPa and 1000–1130 °C. The average liquidus of the rhyolitic magma has been calculated at 970 ± 7 °C, at depths of