Evolution of organic matter in Orgueil, Murchison and Renazzo during parent body aqueous alteration: In situ investigations

Guillou, C. Le; Bernard, Sylvain; Brearley, A. J.; Rémusat, Laurent

doi:10.1016/j.gca.2013.11.020

Cited by 164 publications

(184 citation statements)

References 150 publications

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“…It is important to characterize these changes to understand the formation of prebiotic molecules from the molecular cloud and protoplanetary disk stage to their incorporation in meteorites. While organic matter in the CM2.5 chondrite Murchison is studied extensively (Cronin and Chang, 1993;Cody and Alexander, 2005;Pizzarello et al, 2006;Derenne and Robert, 2010;LeGuillou et al, 2014), only recently a comparison was made between this chondrite and the weakly altered CM2.8 Paris (Vinogradoff et al, 2017). Collectively, these results suggest that hydrothermal alteration on the CM parent body induced aromatization and oxidation of the IOM.…”

Section: Introductionmentioning

confidence: 89%

Isotope record of mineralogical changes in a spectrum of aqueously altered CM chondrites

Kooten

Nagashima

Kasama

et al. 2018

Geochimica et Cosmochimica Acta

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The recent fall of the relatively unaltered CM chondrite Maribo provides a unique opportunity to study the early stages of aqueous alteration on the CM chondrite parent body. We show using transmission electron microscopy of a matrix FIBsection from Maribo that this meteorite mainly appears to consist of tochilinite-cronstedtite intergrowths (TCIs), but also contains regions of amorphous or nanocrystalline silicates, anhydrous silicates and FeNi metal aggregates with thin iron oxide rims, suggesting that it experienced aqueous alteration to a relatively small degree. A comparison of Maribo with increasingly altered CM chondrites such as Jbilet Winselwan and Bells shows that during progressive aqueous alteration (1) the TCIs are replaced by coarser sulfides and increasingly Mg-rich serpentine, and (2) the abundance of 15 N-rich hotspots increases, whereas the magnitude of their 15 N enrichment decreases. We observe that the overall N isotope variability related to aqueous alteration is an order of magnitude lower than the variability observed between different chondrite groups. We suggest these high order differences are the result of heterogeneous accretion of insoluble or soluble organic carriers of 15 N to the different chondrite parent bodies. D/H ratios of matrices from Maribo, Jbilet Winselwan and Bells increase with progressive aqueous alteration, a trend that is opposite to expectations of mixing between D-poor water and D-rich organic matter. We argue that this behaviour cannot be related to Fe oxidation or serpentinization reactions and subsequent loss of D-poor H 2 gas. We offer an alternative hypothesis and suggest that CM chondrites experienced two-stage aqueous alteration. During the first stage occurring at relatively low temperature, mixing of increasing amounts of D-poor water with D-rich organic matter results in a decrease of D/H ratio with increasing degree of alteration. During the second stage of alteration occurring at relatively high temperature (T < 300°C), decomposition of TCIs in CMs of petrologic type <2.7 releases gaseous D-poor water that results in increase of the D/H ratio of the CM matrices. Finally, we report on changes in the organic structure of Maribo, Jbilet Winselwan and Bells using Carbon-K and Nitrogen-K edge electron energy loss spectroscopy. The organic matter initially has higher aromatic/aliphatic ratios (e.g., Maribo) and lower abundances of ketone and carboxyl functional groups, which we suggest are the result of chemical degradation of double bonded carbon from oxidation during hydrothermal

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Section: Introductionmentioning

confidence: 89%

Isotope record of mineralogical changes in a spectrum of aqueously altered CM chondrites

Kooten

Nagashima

Kasama

et al. 2018

Geochimica et Cosmochimica Acta

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“…[16] Recent joint analysis by structure-selective imaging methods such as synchrotron-based scanning transmission X-ray microscopy, transmission electron microscopy, nano-secondary ion mass spectrometry and X-ray absorption near edge structure (C-XANES) has suggested presence of two distinct reservoirs of Murchison organic matter: a set of individual grains, which was proposed to represent mainly insoluble Murchison organic matter, and the socalled diffuse organic matter, which supposedly has resulted from aqueous alteration. [7,17,18] According to C-XANES data, the diffuse organic matter is aliphatic-rich and carboxyl-rich and likely contains carbonate derivatives, whereas it appears relatively depleted in keto groups and aromatics; it is intimately associated with phyllosilicate nanodomains and probably enriched in the soluble fraction of Murchison organic matter. [7,18] Here, we have characterized a methanolic Murchison extract, which according to FTICR mass spectrometry contains the most diverse suite of soluble organic molecules, [11,12] by 800-MHz onedimensional (1D) and two-dimensional (2D) NMR spectroscopy to better constrain its proton and carbon chemical environments.…”

Section: Introductionmentioning

confidence: 99%

Nontarget analysis of Murchison soluble organic matter by high‐field NMR spectroscopy and FTICR mass spectrometry

Hertkorn

Harir

Schmitt‐Kopplin

2015

Magnetic Reson in Chemistry

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High-field NMR spectra of Murchison meteorite methanolic extracts revealed primarily aliphatic extraterrestrial organic matter (EOM) with near statistical branching of commonly C(3-5) units separated by heteroatoms and aromatic units. The ratios of CCH, OCH and C(sp2)H units were 89 : 8 : 3, whereas carbon-based aliphatic chain termination was in the order methyl > -COOH > -CH(CH3)COOH. Aliphatic methine carbon was abundant, but its weak NMR signatures were primarily deduced from JRES (J-resolved) NMR spectra. Carbon NMR spectra were dominated by methylene and methyl carbon; strong apodization revealed methine carbon, of which about 20% was aromatic. Extrapolation provided 5-7% aromatic carbon present in Murchison soluble EOM. Compositional heterogeneity in Murchison methanolic extracts was visible in NMR and Fourier transform ion cyclotron (FTICR) mass spectra obtained from a few cubic millimeters of solid Murchison meteorite; increasing sample size enhanced uniformity of NMR spectra. Intrinsic chemical diversity and pH-dependent chemical shift variance contributed to the disparity of NMR spectra. FTICR mass spectra provided distinct clustering of CHO/CHOS and CHNO/CHNOS molecular series and confirmed the prevalence of aliphatic/alicyclic (73%) over single aromatic (21%) and polyaromatic (6%) molecular compositions, suggesting extensive aliphatic substitution of aromatic units as proposed by NMR. Murchison soluble EOM molecules feature a center with enhanced aromatic and heteroatom content, which provides rather diffuse and weak NMR signatures resulting from a huge overall chemical diversity. The periphery of Murchison EOM molecules comprises flexible branched aliphatic chains and aliphatic carboxylic acids. These project on narrow ranges of chemical shift, facilitating observation in one-dimensional and two-dimensional NMR spectra. The conformational entropy provided by these flexible surface moieties facilitates the solubility of EOM.

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“…These investigations are important to understand the origins and evolution of complex organic compounds in ancient meteoritic materials that contributed to the organic inventory of early Earth. Such combined studies have so far been performed, e.g., on organic grains in the Tagish Lake meteorite (15,24), IDPs (5,13,25), comet 81P/Wild 2 material (9, 10), insoluble organic matter (IOM) extracted from meteorites (11,26), and matrix regions in Renazzo-type (CR) and Ivuna-type (CI) chondrites (27)(28)(29) all applying only standard TEM techniques. Recently, synchrotron X-ray absorption near-edge structure (XANES) analyses have been performed on these organic grains before further TEM investigations (e.g., refs.…”

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confidence: 99%

Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites

Vollmer

Kepaptsoglou

Leitner³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Isotopically anomalous carbonaceous grains in extraterrestrial samples represent the most pristine organics that were delivered to the early Earth. Here we report on gentle aberration-corrected scanning transmission electron microscopy investigations of eight 15 N-rich or D-rich organic grains within two carbonaceous Renazzo-type (CR) chondrites and two interplanetary dust particles (IDPs) originating from comets. Organic matter in the IDP samples is less aromatic than that in the CR chondrites, and its functional group chemistry is mainly characterized by C-O bonding and aliphatic C. Organic grains in CR chondrites are associated with carbonates and elemental Ca, which originate either from aqueous fluids or possibly an indigenous organic source. One distinct grain from the CR chondrite NWA 852 exhibits a rim structure only visible in chemical maps. The outer part is nanoglobular in shape, highly aromatic, and enriched in anomalous nitrogen. Functional group chemistry of the inner part is similar to spectra from IDP organic grains and less aromatic with nitrogen below the detection limit. The boundary between these two areas is very sharp. The direct association of both IDP-like organic matter with dominant C-O bonding environments and nanoglobular organics with dominant aromatic and C-N functionality within one unique grain provides for the first time to our knowledge strong evidence for organic synthesis in the early solar system activated by an anomalous nitrogen-containing parent body fluid. solar nebula | organic matter | meteorites | comets | transmission electron microscopy P rimitive extraterrestrial materials, including unmetamorphosed carbonaceous chondrites, chondritic porous interplanetary dust particles (CP-IDPs), carbonaceous Antarctic micrometeorites, and material from comet 81P/Wild 2, contain isotopically anomalous carbonaceous matter typically enriched in D and/or 15 N compared with the Earth and bulk meteorites (1-11). This carbonaceous matter occurs as diffuse material but also in the form of sub-μm-to μm-sized grains that are extremely enriched in D and/or 15 N and therefore stand out in isotopic maps as so-called "hot spots." These hot spots represent good candidates to study ancient organic compounds that may have served as precursors for the prebiotic history of the early Earth. In many, but not all, cases, the isotopic hot spots occur as so-called "nanoglobules," which are observed as hollow or compact carbonaceous sub-μm spheres in a wide range of primitive extraterrestrial samples (e.g., refs. 11-16). The most widely accepted theory for the origins of the anomalies invokes exothermic ion-molecule isotope exchange reactions at very low temperatures (<25 K) in cold interstellar clouds or the outer reaches of the nascent solar nebula (e.g., refs. 6, 7, 17, and 18). A second possible mechanism for the observed 15 N enrichments is N 2 self-shielding, in which optical depth effects lead to isotopeselective photodissociation (19)(20)(21)(22), but the applicability of the N 2 self-shielding m...

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Evolution of organic matter in Orgueil, Murchison and Renazzo during parent body aqueous alteration: In situ investigations

Cited by 164 publications

References 150 publications

Isotope record of mineralogical changes in a spectrum of aqueously altered CM chondrites

Isotope record of mineralogical changes in a spectrum of aqueously altered CM chondrites

Nontarget analysis of Murchison soluble organic matter by high‐field NMR spectroscopy and FTICR mass spectrometry

Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites

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