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Abstract Garnet peridotite xenoliths have been rarely reported from suboceanic mantle. Petrographic and geochemical characteristics of garnet-bearing oceanic peridotite xenoliths provide precious information on dynamics of the suboceanic lithosphere and asthenosphere interaction. We examined a lherzolite xenolith included in olivine nephelinite lava from Aitutaki Island, a member of the Cook-Austral volcanic chain. The lherzolite xenolith contains reddish fine-grained (

Abstract The microtexture of graphite exposed on the polished surface was studied using confocal laser scanning microscopy, laser Raman spectroscopy, and focused ion beam–transmission electron microscopy (FIB–TEM) to elucidate the effect on surface condition and crystallinity of graphite by polishing process. The polished surface of the graphite was divided into a flat part with no irregularities and a grooved band with a width of

The article presents a study which showed that high-temperature anhydrous primary minerals in Ryugu and CI chondrites exhibit a bimodal distribution of oxygen isotopic compositions. Topics discussed include bimodal distributions of oxygen (O) isotopic compositions of primary minerals, origin of O-poor primary minerals in Ryugu and Ivuna, and origin of O-rich primary minerals in Ryugu and Ivuna.