Lava samples in this study classify as tephrites and basanites based on petrographic observations, with tephrites erupted earlier than basanites within each eruption (see geological setting in the Supplementary Information). Both rock types are porphyritic and contain large crystals of clinopyroxene with inclusions of Fe–Ti oxides. Tephrites are distinguished by the presence of amphibole (kaersutite) and absence of olivine, while basanites contain olivine and lack amphibole (Fig. 2). Clinopyroxene forms large crystals in all three eruptions (up to 5 mm in size), together with microlites smaller than 100 µm. Clinopyroxene crystals can also be found as mineral inclusions in rare plagioclase crystals18. Across all eruptions, large clinopyroxene crystals can host inclusions of apatite, Fe–Ti oxides, and glassy to microcrystalline melt inclusions (Fig. 2). The groundmass is microcrystalline and predominantly composed of plagioclase, clinopyroxene, and Fe–Ti oxides, as well as olivine in the basanites and amphibole in the tephrites (Fig. 2). Clinopyroxene crystals can be broadly divided into three main textural zones across the three eruptions: core, inner rim, and outer rim. The cores represent the innermost parts of the crystals and are texturally complex, characterized by patchy or more rarely sector zoning in back-scattered electron (BSE) images (Fig. 2G-I). Under...

Mineral Matters #450