Petrographic, chemical and spectroscopic evidence for thermal metamorphism in carbonaceous chondrites I: CI and CM chondrites

Tonui, E.; Zolensky, M. E.; Hiroi, T.; Nakamura, Tomoki; Lipschutz, M. E.; Wang, Ming Sheng; Okudaira, Kyoko

doi:10.1016/j.gca.2013.10.053

Cited by 162 publications

(244 citation statements)

References 39 publications

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“…Broad reflections in XRD patterns indicate that the olivine within the CI-like meteorites is fine-grained and poorly crystalline (e.g. King et al 2015), consistent with it being a secondary phase that recrystallized from the phyllosilicate during thermal metamorphism (Tonui et al 2003(Tonui et al , 2014Nakamura 2005). This implies that essentially all of the original silicates were hydrated, as is observed in the CI chondrites (e.g.…”

Section: Degree Of Aqueous Alterationmentioning

confidence: 75%

“…Troilite is much more abundant in these CI-like chondrites (~20 vol.%) than in CI chondrites (King et al 2015) and has been observed breaking down into Femetal around this temperature (Tonui et al 2014). Alternatively, this could result from high temperature decomposition of a carbonate phase (e.g.…”

Section: Tga-ci and Ci-like Chondritesmentioning

confidence: 99%

“…Of these, Y-82162, Y-86029 and Y-980115 have been identified as thermally altered CI-like chondrites (Tomeoka et al 1989;Ikeda 1991;Nakamura 2005;Tonui et al 2003Tonui et al , 2014King et al 2015). Evidence for thermal metamorphism comes from the dehydration of phyllosilicates and recrystallization back into fine-grained olivine (Nakamura 2005;Tonui et al 2014), bulk O isotopic compositions shifted to higher values (δ 17 O~12, δ 18 O~22) than the CIs (Clayton and Mayeda 1999), and the destruction and modification of organics (Burton et al 2014).…”

Section: Introductionmentioning

confidence: 99%

“…Evidence for thermal metamorphism comes from the dehydration of phyllosilicates and recrystallization back into fine-grained olivine (Nakamura 2005;Tonui et al 2014), bulk O isotopic compositions shifted to higher values (δ 17 O~12, δ 18 O~22) than the CIs (Clayton and Mayeda 1999), and the destruction and modification of organics (Burton et al 2014). Trace element chemistry and X-ray diffraction (XRD) patterns have been used to estimate that the temperature of the thermal metamorphism exceeded 500°C (Nakamura 2005;Tonui et al 2003Tonui et al , 2014King et al 2015).…”

Section: Introductionmentioning

confidence: 99%

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Characterising the CI and CI-like carbonaceous chondrites using thermogravimetric analysis and infrared spectroscopy

et al. 2015

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The CI and CI-like chondrites provide a record of aqueous alteration in the early solar system. However, the CI-like chondrites differ in having also experienced a late stage period of thermal metamorphism. In order to constrain the nature and extent of the aqueous and thermal alteration, we have investigated the bulk mineralogy and abundance of H 2 O in the CI and CI-like chondrites using thermogravimetric analysis and infrared spectroscopy. The CI chondrites Ivuna and Orgueil show significant mass loss (28.5-31.8 wt.%) upon heating to 1000°C due to dehydration and dehydroxylation of abundant phyllosilicates and Fe-(oxy)hydroxides and the decomposition of Fe-sulphides, carbonates and organics. Infrared spectra for Ivuna and Orgueil have a prominent 3-μm feature due to bound −OH/H 2 O in phyllosilicates and Fe-(oxy)hydroxides and only a minor 11-μm feature from anhydrous silicates. These characteristics are consistent with previous studies indicating that the CI chondrites underwent near-complete aqueous alteration. Similarities in the total abundance of H 2 O and 3 μm/11 μm ratio suggest that there is no difference in the relative degree of hydration experienced by Ivuna and Orgueil. In contrast, the CI-like chondrites Y-82162 and Y-980115 show lower mass loss (13.8-18.8 wt.%) and contain >50 % less H 2 O than the CI chondrites. The 3-μm feature is almost absent from spectra of Y-82162 and Y-980115 but the 11-μm feature is intense. The CI-like chondrites experienced thermal metamorphism at temperatures >500°C that initially caused dehydration and dehydroxylation of phyllosilicates before partial recrystallization back into anhydrous silicates. The surfaces of many C-type asteroids were probably heated through impact metamorphism and/or solar radiation, so thermally altered carbonaceous chondrites are likely good analogues for samples that will be returned by the Hayabusa-2 and OSIRIS-REx missions.

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Section: Degree Of Aqueous Alterationmentioning

confidence: 75%

Section: Tga-ci and Ci-like Chondritesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characterising the CI and CI-like carbonaceous chondrites using thermogravimetric analysis and infrared spectroscopy

et al. 2015

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“…A previous amino acid analysis of Y-980115 conducted by Burton et al (2014a) showed that Y-980115 had a low total amino acid abundancẽ 3 nmol/g (which translates to~300 ppb, with a molar mass of~100 g/mol). This low amino acid abundance makes Y-980115 distinct from other CI chondrites such as Orgueil and Ivuna (total amino acid abundance >4000 ppb), which accounts for its alternative nomenclature as "CI-like chondrite," commonly named for a range of chondrites with isotopic and petrographic characteristics that differ remarkably from typical CI chondrites (Tonui et al 2014). Modal mineralogy of Y-980115 indicates that it has experienced short-lived thermal metamorphism above 500°C (King et al 2015b), which is notably lower than the estimated peak temperature (<220°C) for Orgueil insoluble organic matter (IOM) obtained from micro-Raman spectroscopy (Busemann et al 2007) (although micro-Raman spectroscopy is not sensitive to weaker thermal events such as flash-heating or impact (Quirico et al 2005)) and inferred from its organic content (Nagy et al 1963).…”

Section: Low Amino Acid Abundances Of Y-980115 and Alha77003mentioning

confidence: 99%

Amino acid compositions in heated carbonaceous chondrites and their compound-specific nitrogen isotopic ratios

et al. 2016

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A novel method has been developed for compound-specific nitrogen isotope compositions with an achiral column which was previously shown to offer high precision for nitrogen isotopic analysis. We applied the method to determine the amino acid contents and stable nitrogen isotopic compositions of individual amino acids from the thermally metamorphosed (above 500°C) Antarctic carbonaceous chondrites Ivuna-like (CI)1 (or CI-like) Yamato (Y) 980115 and Ornans-like (CO)3.5 Allan Hills (ALH) A77003 with the use of gas chromatography/combustion/isotope ratio mass spectrometry. ALHA77003 was deprived of amino acids due to its extended thermal alteration history. Amino acids were unambiguously identified in Y-980115, and the δ 15 N values of selected amino acids (glycine +144.8 ‰; α-alanine +121.2 ‰) are clearly extraterrestrial. Y-980115 has experienced an extended period of aqueous alteration as indicated by the presence of hydrous mineral phases. It has also been exposed to at least one post-hydration short-lived thermal metamorphism. Glycine and alanine were possibly produced shortly after the accretion event of the asteroid parent body during the course of an extensive aqueous alteration event and have abstained from the short-term post-aqueous alteration heating due to the heterogeneity of the parent body composition and porosity. These carbonaceous chondrite samples are good analogs that offer important insights into the target asteroid Ryugu of the Hayabusa-2 mission, which is a C-type asteroid likely composed of heterogeneous materials including hydrated and dehydrated minerals.

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Organic Matter in Interplanetary Dusts and Meteorites

Quirico

Bonal

2018

Biosignatures for Astrobiology

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Petrographic, chemical and spectroscopic evidence for thermal metamorphism in carbonaceous chondrites I: CI and CM chondrites

Cited by 162 publications

References 39 publications

Characterising the CI and CI-like carbonaceous chondrites using thermogravimetric analysis and infrared spectroscopy

Characterising the CI and CI-like carbonaceous chondrites using thermogravimetric analysis and infrared spectroscopy

Amino acid compositions in heated carbonaceous chondrites and their compound-specific nitrogen isotopic ratios

Organic Matter in Interplanetary Dusts and Meteorites

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