Hydrogen isotopic evidence for nebular pre-hydration and the limited role of parent-body processes in CM chondrites

Marrocchi, Yves; Rigaudier, Thomas; Piralla, Maxime; Piani, Laurette

doi:10.1016/j.epsl.2023.118151

Cited by 9 publications

(7 citation statements)

References 72 publications

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“…Making the simplified assumption that all the water in UOCs is in the matrix, utilizing matrix abundances from Grossman and Brearley (2005), or where unavailable assuming that samples have a matrix abundance of 10%, and using H 2 O abundances from Table 1, we estimate the water abundance of the matrix at 4.8-8.2 wt% H 2 O for UOC falls ≤3.3 (Figure 5). This is comparable to the calculated matrix water contents, as determined using bulk water contents and individual chondrite matrix abundances, of some phyllosilicate-rich CR and CM chondrites (Figure 5), where the CM chondrites with the lowest H 2 O values and least parent body alteration are Paris (CM2.7; Piani & Marrocchi, 2018) and Asuka 12,236 (CM2.9; Marrocchi et al, 2023). Of note, we measured the highest water abundance in St Mary's County, which has a terrestrial-like D/H ratio.…”

Section: Bulk Chondrite Water Contentssupporting

confidence: 84%

“…In addition, other processes such as the aqueous oxidation of iron-bearing phases followed by H 2 loss and Rayleightype isotopic fractionation are likely ineffective for enriching D in water-rich chondrites, due to the buffering by large amounts of water. For CM chondrites, for example, this proposed mechanism is at odds with the observation that the least-altered CMs Paris and Asuka 12236 contain unoxidized metal and are enriched in D compared to more altered CMs (Marrocchi et al, 2023). Altogether, this suggests that the D-rich isotopic compositions of pristine UOCs are inherited characteristics involving processes having occurred in molecular cloud and/or protosolar nebula settings.…”

Section: D/h Variation Across the Solar Systemmentioning

confidence: 98%

“…Calculated matrix H 2 O abundance versus petrologic type (combining bulk H 2 O abundances and matrix abundances of 10% for OCs and 40%-99% for CCs, based off groups or, where available, individual samples). Data from this study (falls only) are represented in pink and all other points are CC literature data (Alexander et al, 2010(Alexander et al, , 2013Marrocchi et al, 2023;Piani & Marrocchi, 2018;Vacher et al, 2020;Weisberg et al, 2006), with CM and CV subtype classifications by Rubin et al (2007) and Bonal et al (2004), respectively. TL, Tagish Lake.…”

Section: Bulk Hydrogen Isotope Composition Of Uocsmentioning

confidence: 99%

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Bulk mineralogy, water abundance, and hydrogen isotope composition of unequilibrated ordinary chondrites

Grant

Tartèse

Jones

et al. 2023

Meteorit & Planetary Scien

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The origin and transport of water in the early Solar System is an important topic in both astrophysics and planetary science, with applications to protosolar disk evolution, planetary formation, and astrobiology. Of particular interest for understanding primordial water transport are the unequilibrated ordinary chondrites (UOCs), which have been affected by very limited alteration since their formation. Using X‐ray diffraction and isotope ratio mass spectrometry, we determined the bulk mineralogy, H2O content, and D/H ratios of 21 UOCs spanning from petrologic subtypes 3.00–3.9. The studied UOC falls of the lowest subtypes contain approximately 1 wt% H2O, and water abundance globally decreases with increasing thermal metamorphism. In addition, UOC falls of the lowest subtypes have elevated D/H ratios as high as those determined for some outer Solar System comets. This does not easily fit with existing models of water in the protoplanetary disk, which suggest D/H ratios were low in the warm inner Solar System and increased radially. These new analyses confirm that OC parent bodies accreted a D‐rich component, possibly originating from either the outer protosolar nebula or from injection of molecular cloud streamers. The sharp decrease of D/H ratios with increasing metamorphism suggests that the phase(s) hosting this D‐rich component is readily destroyed through thermal alteration.

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Section: Bulk Chondrite Water Contentssupporting

confidence: 84%

Section: D/h Variation Across the Solar Systemmentioning

confidence: 98%

Section: Bulk Hydrogen Isotope Composition Of Uocsmentioning

confidence: 99%

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Bulk mineralogy, water abundance, and hydrogen isotope composition of unequilibrated ordinary chondrites

Grant

Tartèse

Jones

et al. 2023

Meteorit & Planetary Scien

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“…Additionally, although the FGR is porous (Figure 9d), this does not necessarily equate to increased permeability (Bland et al., 2009) and therefore the amorphous silicate grain could be preserved intact through a minor aqueous alteration event which may have produced the fine wisps of phyllosilicate. Recent studies have suggested that amorphous silicates may be a carrier for water in the solar system and were accreted in a partially hydrated state from the nebular (Marrocchi et al., 2023).…”

Section: Discussionmentioning

confidence: 99%

Brecciation at the grain scale within the lithologies of the Winchcombe Mighei‐like carbonaceous chondrite

Daly,

Suttle,

Lee

et al. 2024

Meteorit & Planetary Scien

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The Mighei‐like carbonaceous (CM) chondrites have been altered to various extents by water–rock reactions on their parent asteroid(s). This aqueous processing has destroyed much of the primary mineralogy of these meteorites, and the degree of alteration is highly heterogeneous at both the macroscale and nanoscale. Many CM meteorites are also heavily brecciated juxtaposing clasts with different alteration histories. Here we present results from the fine‐grained team consortium study of the Winchcombe meteorite, a recent CM chondrite fall that is a breccia and contains eight discrete lithologies that span a range of petrologic subtypes (CM2.0–2.6) that are suspended in a cataclastic matrix. Coordinated multitechnique, multiscale analyses of this breccia reveal substantial heterogeneity in the extent of alteration, even in highly aqueously processed lithologies. Some lithologies exhibit the full range and can comprise nearly unaltered coarse‐grained primary components that are found directly alongside other coarse‐grained components that have experienced complete pseudomorphic replacement by secondary minerals. The preservation of the complete alteration sequence and pseudomorph textures showing tochilinite–cronstedtite intergrowths are replacing carbonates suggest that CMs may be initially more carbonate rich than previously thought. This heterogeneity in aqueous alteration extent is likely due to a combination of microscale variability in permeability and water/rock ratio generating local microenvironments as has been established previously. Nevertheless, some of the disequilibrium mineral assemblages observed, such as hydrous minerals juxtaposed with surviving phases that are typically more fluid susceptible, can only be reconciled by multiple generations of alteration, disruption, and reaccretion of the CM parent body at the grain scale.

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“…44−46 However, a recent comprehensive characterization of the hydrogen isotopic composition of water-rich chondrites suggests that their IOM experienced minimal modification during fluid circulation. 47 All four processes described above have been successfully implemented in laboratory experiments to produce synthetic samples mimicking part of the compositional and structural properties of chondritic organics. These analog samples thus offer a unique opportunity to explore how the range of chemophysical conditions (temperature, molecular abundances, and irradiation regime) found in PPDs may influence the properties of the resulting primordial organic matter.…”

Section: Introductionmentioning

confidence: 99%

Effect of Nitrogen on the Structure and Composition of Primordial Organic Matter Analogs

Lévêque,

Queffelec,

Sotin

et al. 2024

ACS Earth Space Chem.

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Organic molecules are ubiquitous in primitive solar system bodies such as comets and asteroids. These primordial organic compounds may have formed in the interstellar medium and in protoplanetary disks (PPDs) before being accreted and further transformed in the parent bodies of meteorites, icy moons, and dwarf planets. The present study describes the composition of primordial organics analogs produced in a laboratory simulator of the PPD (the Nebulotron experiment at the CRPG laboratory) with nitrogen contents varying from N/C < 0.01 to N/C = 0.63. We present the first Fourier transform ion cyclotron resonance mass spectrometry analysis of these analogs. Several thousands of molecules with masses between m/z 100 and 500 are characterized. The mass spectra show a Gaussian shape with maxima around m/z 250. Highly condensed polyaromatic hydrocarbons (PAH) are the most common compounds identified in the samples with lower nitrogen contents. As the amount of nitrogen increases, a dramatic increase of the chemical diversity is observed. Nitrogen-bearing compounds are also dominated by polyaromatic hydrocarbons (PANH) made of 5-and 6-membered rings containing up to four nitrogen atoms, including triazine and pyrazole rings. Such N-rich aromatic species are expected to decompose easily in the presence of water at higher temperatures. Pure carbon molecules are also observed for samples with relatively small fractions of nitrogen. MS peaks compatible with the presence of amino acids and nucleobases, or their isomers, are detected. When comparing these Nebulotron samples with the insoluble fraction of the Paris meteorite organic matter, we observe that the samples with intermediate N/C ratios bracketing that of the Paris insoluble organic matter (IOM) display relative proportions of the CH, CHO, CHN, and CHNO chemical families also bracketing those of the Paris IOM. Our results support that Nebulotron samples are relevant laboratory analogs of primitive chondritic organic matter.

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Hydrogen isotopic evidence for nebular pre-hydration and the limited role of parent-body processes in CM chondrites

Cited by 9 publications

References 72 publications

Bulk mineralogy, water abundance, and hydrogen isotope composition of unequilibrated ordinary chondrites

Bulk mineralogy, water abundance, and hydrogen isotope composition of unequilibrated ordinary chondrites

Brecciation at the grain scale within the lithologies of the Winchcombe Mighei‐like carbonaceous chondrite

Effect of Nitrogen on the Structure and Composition of Primordial Organic Matter Analogs

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