Three-dimensional multiscale assembly of phyllosilicates, organics, and carbonates in small Ryugu fragments

Abstract

We report μm-scale nondestructive infrared (IR) hyperspectral results (IR computed tomography, IR-CT) in 3-D and IR surface imaging, IR-S) in 2-D, at SOLEIL) combined with X-ray nano-computed tomography analyses (at SPring-8) performed on eight small Ryugu fragments extracted from mm-sized grains coming both from touchdown first and second sites. We describe the multiscale assembly of phyllosilicates, carbonates, sulfides, oxides, and organics. Two types of silicates, as well as diverse kinds of organic matter, were detected inside Ryugu material. Their spatial correlations are described to discuss the role of the mineralogical microenvironments in the formation/evolution of organic matter. In particular, we have shown that there is a redistribution of the organic matter diffuse component during aqueous alteration on the parent body, with a preferential circulation among fine-grained phyllosilicates.