Chemistry in Retrieved Ryugu Asteroid Samples Revealed by Non-Invasive X-ray Microanalyses: Pink-Beam Fluorescence CT and Tender-Energy Absorption Spectroscopy

Journal Article · 21 April 2024 · Geosciences

DOI: https://doi.org/10.3390/geosciences14040111 · OSTI ID:2367443

Northrup, Paul  ^[1]; Tappero, Ryan ^[2]; Glotch, Timothy D.  ^[1]; Flynn, George J. ^[3]; Yesiltas, Mehmet ^[1]; Kebukawa, Yoko  ^[4]; Flores, Leonard ^[1]; Gemma, Marina E.  ^[1]; Piccione, Gavin ^[5]

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1. Stony Brook Univ., NY (United States)
2. Stony Brook Univ., NY (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States)
3. State Univ. of New York (SUNY), Plattsburgh, NY (United States)
4. Tokyo Institute of Technology (Japan)
5. Brown Univ., Providence, RI (United States)

The Hayabusa2 space mission recently retrieved 5.4 g of material from asteroid Ryugu, providing the first direct access to pristine material from a carbonaceous asteroid. This study employs a novel combination of non-invasive synchrotron X-ray techniques to examine microscale chemistry (elemental distributions and element-specific chemical speciation and local structure) inside Ryugu grains without physically cutting the samples. Manganese primarily occurs in carbonate: Mn-bearing dolomite with minor earlier ankerite. Iron sulfides present as large single grains and as smaller particles in the finer-grained matrix are both predominantly pyrrhotite. At the 5 μm scale, Fe sulfides do not show the mineralogical heterogeneity seen in many carbonaceous meteorites but exhibit some heterogeneous localized oxidation. Iron is present often as intergrowths of oxide and sulfide, indicating incomplete replacement. Trace selenium substitutes for S in pyrrhotite. Copper is present as Fe-poor Cu sulfide. These results demonstrate multiple episodes of fluid alteration on the parent body, including partial oxidation, and help constrain the sequence or evolution of fluids and processes that resulted in the current grain-scale mineralogical composition of Ryugu materials.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); National Aeronautics and Space Administration (NASA)
• Grant/Contract Number: SC0012704
• OSTI ID: 2367443
• Report Number(s): BNL--225629-2024-JAAM
• Journal Information: Geosciences, Journal Name: Geosciences Journal Issue: 4 Vol. 14; ISSN 2076-3263
• Publisher: MDPICopyright Statement
• Country of Publication: United States
• Language: English