Origin and Evolution of the Holocene Magmatic System at Sakurajima Volcano, Japan.

This article focuses on the petrological and geochemical evolution of the Holocene magmatic system at Sakurajima volcano, one of Japan's most active volcanoes, developed through post-caldera activity at the Aira caldera. The study identifies two distinct groups of volcanic products: a low-P₂O₅ group (>1.6 ka) derived primarily from partial melting of heterogeneous lower crustal materials with varying melting degrees, and a high-P₂O₅ group (<1.3 ka) formed by binary mixing between mantle-derived mafic magmas and felsic magmas produced by fractional crystallisation of higher-degree lower crustal melts. The research concludes that Holocene magmatism at Sakurajima was controlled by intermittent discharges of partial melts from a lower crustal source region that existed well before the caldera-forming eruption at 30 ka, and that the voluminous rhyolitic magmas and their source materials from the Aira caldera-forming event were not involved in the Holocene magmatic system.