Search for meteoritic GEMS I: Comparison of amorphous silicates in Paris and Acfer 094 chondrite matrices and in anhydrous chondritic interplanetary dust particles

Ohtaki, Kenta K.; Ishii, H. A.; Bradley, J. P.; Villalon, K. L.; Davis, A. M.; Stephan, T.; Bustillo, Karen C.; Ciston, Jim

doi:10.1016/j.gca.2021.05.042

Cited by 23 publications

(25 citation statements)

References 65 publications

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“…4B). This indicates that the GEMS-like objects in Ryugu are at least partially altered, similar to the primitive clasts in the Paris CM chondrite (55)(56)(57).…”

Section: Less Altered Fragmentsmentioning

confidence: 81%

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Nakamura

Matsumoto

Amano

et al. 2023

Science

133

144

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Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed seventeen Ryugu samples measuring 1-8 mm. CO 2 -bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu’s parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and Ca, Al-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed by aqueous alteration reactions at low temperature, high pH, and water/rock ratios < 1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate Ryugu’s parent body formed ~ 2 million years after the beginning of Solar System formation.

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“…4B). This indicates that the GEMS-like objects in Ryugu are at least partially altered, similar to the primitive clasts in the Paris CM chondrite (55)(56)(57).…”

Section: Less Altered Fragmentsmentioning

confidence: 81%

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Nakamura

Matsumoto

Amano

et al. 2023

Science

133

144

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“…Condensates synthesized under oxidizing conditions in the present experiments are similar to GEMS-like materials in the matrices of primitive carbonaceous chondrites, which include only Fe and Ni sulfides and no or rare metals with relatively Fe-rich amorphous silicate compared to GEMS (Greshake 1997;Leroux et al 2015;Nittler et al 2019;Matsumoto et al 2019;Ohtaki et al 2021;Villalon et al 2021). In particular, Fe-rich amorphous silicates with FeS nanoparticles without Fe-metal (Types B and C) are the most consistent with the characteristics of these GEMS-like materials (Leroux et al 2015;Matsumoto et al 2019).…”

Section: Comparison Of Textures Between Synthetic Products With Gems ...mentioning

confidence: 54%

“…Both of these models have been well studied (Bradley 2013;Keller & Messenger 2013), and it has been suggested that GEMS could be key to the origin of the solid materials of the Solar System. GEMS-like materials have also been observed in the matrices of primitive carbonaceous chondrite meteorites (Greshake 1997;Leroux et al 2015;Nittler et al 2019;Matsumoto et al 2019;Ohtaki et al 2021;Villalon et al 2021). These GEMS-like materials differ from GEMS in A&A proofs: manuscript no.…”

Section: Introductionmentioning

confidence: 97%

Condensation of cometary silicate dust using an induction thermal plasma system

Enju

Kawano

Tsuchiyama

et al. 2022

A&A

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Glass with embedded metal and sulfides (GEMS), the major components of chondritic-porous interplanetary dust particles (CP-IDPs), is one of the most primitive materials in the Solar System and may be analogous to the amorphous silicate dust observed in various astronomical environments. Mineralogical characteristics of GEMS should reflect their formation process and condition. In this study, synthetic experiments in the sulfur-bearing system of Fe-Mg-Si-O-S were performed with a systematic change in redox conditions using thermal plasma systems to reproduce the mineralogy and textures of GEMS. The resulting condensates were composed of amorphous silicates with Fe-bearing nano-inclusions. The Fe content and texture in the amorphous silicates as well as the mineral phases of the nanoparticles correlate with redox conditions. Fe dissolved in the amorphous silicate as FeO in oxidizing conditions formed Fe-metal nanoparticles in intermediate redox conditions, and gupeiite (Fe 3 Si) nanoparticles in reducing conditions. In intermediate to reducing redox conditions, Fe-poor amorphous silicate formed a biphasic texture with Mg-and Si-rich regions, indicating liquid immiscibility during the melt phase. Most Fe-metal particles were surrounded by FeS and formed on the surface of amorphous silicate grains. Condensates produced in intermediate to slightly reducing redox conditions resemble GEMS in that they have similar mineral assemblages and chemical compositions to amorphous silicate, except that the Fe-metal grains are absent from the interior of the amorphous silicate grains. This textural difference can be explained by the sulfidation at high temperatures in this study, in contrast to sulfidation occurring at low temperatures in the presence of H 2 in natural GEMS formation. Based on the twoliquid structures observed in the experimental products and in GEMS, also recognized in infrared (IR) spectra, we propose that GEMS condensed as silicate melt under limited redox conditions followed by incorporation of multiple metal grains into the silicate melt or by aggregation of core-shell structured grains before sulfidation of the metallic iron. Condensates produced in oxidizing conditions are similar to GEMS-like material in the matrices of primitive carbonaceous chondrite meteorites, indicating the possibility that they form by direct condensation from nebula gas in relatively oxidizing conditions compared to GEMS.

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“…3 in Matsumoto et al., 2019) in contrast to those in GEMS, which are essentially Fe‐free. In addition, metals are rare or absent in amorphous silicates in primitive meteorites (Bradley, 2019; Ohtaki et al., 2021; Villalon et al., 2021).…”

Section: Discussionmentioning

confidence: 99%

“…These differences are probably related to the different water/rock ratios, as well as different temperatures, periods, and compositions of the aqueous solutions during aqueous alteration. Therefore, ice likely melted more broadly in the parent bodies of these meteorites than in the parent body of the AMM (Bradley, 2019; Ohtaki et al., 2021; Villalon et al., 2021) and that the ice in the parent bodies of these meteorites was only locally preserved (Matsumoto et al., 2019; Nittler et al., 2019).…”

Section: Discussionmentioning

confidence: 99%

Antarctic micrometeorite composed of CP and CS IDP‐like material: A micro‐breccia originated from a partially ice‐melted comet‐like small body

Noguchi

Matsumoto

Yabuta

et al. 2022

Meteorit & Planetary Scien

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Asteroids and comets are thought to form in the inner and outer solar systems, respectively. Chondritic porous and smooth interplanetary dust particles (CP IDPs and CS IDPs, respectively) in the stratosphere are regarded as dust grains from comets and hydrated asteroids, respectively. Here, we describe an Antarctic micrometeorite (AMM) composed of lithologies of both CP and CS IDPs. In addition to the CS IDP-like compact lithology that experienced severe aqueous alteration, the CP IDP-like porous lithology shows evidence of very weak aqueous alteration. The structure of the organic matter in the porous lithology varies from that in the CP IDPs to aromatic-rich organic matter. In contrast, the structure of the organic matter in the compact lithology is homogenous, which is consistent with higher degrees of aqueous alteration. Its structure is more similar to that of CP IDPs and Wild 2 samples than that of meteoritic insoluble organic matter, suggesting that the compact lithology formed from the porous lithology. Some CP IDPs are related to cometary dust streams, such as those originating from 26P/Grigg-Skjellerup. In addition, the presence of this AMM indicates an additional origin of the CP IDPs and their equivalent AMMs. The mineralogy and organic chemistry of this AMM suggest that its parent body was composed of the same building blocks as those of the comets, and later experienced incomplete aqueous alteration. The AMM probably formed as microbreccia in the regolith layer composed of materials from a CP IDP-like crust and a hydrated interior.

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Search for meteoritic GEMS I: Comparison of amorphous silicates in Paris and Acfer 094 chondrite matrices and in anhydrous chondritic interplanetary dust particles

Cited by 23 publications

References 65 publications

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Condensation of cometary silicate dust using an induction thermal plasma system

Antarctic micrometeorite composed of CP and CS IDP‐like material: A micro‐breccia originated from a partially ice‐melted comet‐like small body

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