Prevalence and nature of heating processes in CM and C2-ungrouped chondrites as revealed by insoluble organic matter

Quirico, E.; Bonal, L.; Beck, Pierre; Alexander, Conel M. O'd.; Yabuta, Hikaru; Nakamura, Tomoki; Nakato, Aiko; Flandinet, Laurène; Montagnac, Gilles; Schmitt‐Kopplin, Philippe; Herd, C. D. K.

doi:10.1016/j.gca.2018.08.029

Cited by 99 publications

(112 citation statements)

References 71 publications

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“…Higher CH 2 /CH 3 ratios indicate longer aliphatic chains and/or higher contents of cyclic aliphatic structures, and lower CH 2 /CH 3 ratios indicate shorter chain lengths and/or higher branching levels. The observed higher CH 2 /CH 3 ratios in thermally metamorphosed chondrites are consistent with previous work showing that the CH 2 /CH 3 ratios were higher in IOM from thermally metamorphosed chondrites and heated CMs (e.g., Kebukawa et al 2011;Orthous-Daunay et al 2013;Quirico et al 2018). Considering that the IOM from these thermally metamorphosed chondrites has lower H/C ratios (Alexander et al 2007), the increase in CH 2 /CH 3 ratios is likely due to terminations of CH 3 , rather than due to increasing of chain length.…”

Section: Variations Of Missing C Among Chondrite Groupssupporting

confidence: 92%

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Comparison of FT‐IR spectra of bulk and acid insoluble organic matter in chondritic meteorites: An implication for missing carbon during demineralization

Kebukawa

Alexander

Cody

2019

Meteorit & Planetary Scien

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Past studies of the various separable carbonaceous fractions have been unable to account for all of C in primitive chondrites. In particular, up to 20–50% of the C is lost during acid leaching of bulk samples even after the C in carbonates and soluble organic matter is accounted for. To try to better characterize the nature of this “missing C,” we have compared the bulk infrared (IR) absorption spectra of a number of primitive chondrites with those of their previously reported insoluble organic matter (IOM). The aliphatic C–H stretching bands, in particular, allow us to compare the molecular structures of bulk C with that of IOM. The spectral differences between bulk C and IOM reflect “missing C” phases that were lost during acid leaching, although we cannot completely exclude the possibility that the OM was modified after demineralization. Comparing IR spectra of bulk meteorite powder and IOM suggests that the missing C varies in its molecular structure, and that mildly thermally metamorphosed type 3 chondrites tend to be richer in an aliphatic fraction with lower CH2/CH3 ratios, relative to IOM, compared to aqueously altered carbonaceous chondrites (CI/CM/CR). The missing C is most likely released from acid‐labile functional groups, such as esters, acetals, and amides, during demineralization, although it cannot be ruled out that some fraction of the missing C is in small grains that are difficult to recover from suspension, or in water‐soluble compounds trapped in phyllosilicates.

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Section: Variations Of Missing C Among Chondrite Groupssupporting

confidence: 92%

“…; Quirico et al. ). Considering that the IOM from these thermally metamorphosed chondrites has lower H/C ratios (Alexander et al.…”

Section: Discussionmentioning

confidence: 97%

Comparison of FT‐IR spectra of bulk and acid insoluble organic matter in chondritic meteorites: An implication for missing carbon during demineralization

Kebukawa

Alexander

Cody

2019

Meteorit & Planetary Scien

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“…2A). The Raman parameters change in the same way with maturation of coal (Quirico et al, 2005;Bower et al, 2013), and IOM from meteorites exhibit similar modification due to parent body alteration (Busemann et al, 2007;Quirico et al, 2018). The relatively small changes to the Raman parameters in the samples in this study (G-band FWHM 88-101 cm -1 ) compared to those in natural samples (G-band FWHM 53-109 cm -1 among carbonaceous chondrites; Busemann et al, 2007) is almost certainly a kinetic effect.…”

Section: Effects Of Flash Heating On Iomsupporting

confidence: 58%

“…A linear baseline was applied to the each of these regions and the spectra were normalized so that the absorbance at 1600 cm -1 = 1 (c.f., Kebukawa et al, 2011;Querico et al, 2018;Remusat et al, 2019). Following Quirico et al (2018), three parameters were extracted from the spectra: (1) the abundance of carbonyl (C=O) relative to C=C given by the normalized intensity of the peak at ~ 1710 cm -1 , (2) the aliphatic CH2/CH3 ratio from the intensities of the antisymmetric stretching bands at ~2925 cm -1 and 2955 cm -1 , and (3) the aliphatic abundance ( ) relative to C=C given by the integrated absorbance of the normalized aliphatic stretching bands in the range 3000-2800 cm -1 . In some spectra, a broad feature in the 3600-3200 cm -1 region, likely due to O-H stretching modes (Kebukawa et al, 2011), was detected.…”

Section: Microftirmentioning

confidence: 99%

The effects of atmospheric entry heating on organic matter in interplanetary dust particles and micrometeorites

Riebe

Foustoukos

Alexander

et al. 2020

Earth and Planetary Science Letters

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Interplanetary dust particles (IDPs) were likely major sources of extraterrestrial organics at the surface of the early Earth. However, IDPs experience heating to >500 °C for up to several seconds during atmospheric entry. In this study, we aim to understand the effects of atmospheric entry heating on the dominant organic component in IDPs by conducting flash heating experiments (4 s to 400 °C, 600 °C, 800 °C, and 1000 °C) on insoluble organic matter (IOM) extracted from the meteorite Cold Bokkeveld (CM2). For each of the experimental charges, the bulk isotopic compositions of H, N, and C were analyzed using IRMS, the H isotopic heterogeneities (occurrence of hotspots) of the samples were measured by NanoSIMS, and the functional group chemistry and ordering of the IOM was evaluated using FTIR and Raman spectroscopy, respectively. Organic matter in particles heated to 600 °C during atmospheric entry experienced significant alteration. Loss of isotopically heavy, labile H and N groups results in decreases in bulk 15 N, H/C and, upon 800 °C, in N/C. The H heterogeneity was not greatly affected by flash heating to 600 °C, although the hotspots tended to be less isotopically anomalous in the 600 °C sample than in the 400 °C sample. However, the hotspots all but disappeared in the 800 °C sample. Loss of C=O groups occurred at 800 °C. Based on the Raman G-band characteristics, the heating resulted in increased ordering of the polyaromatic component of the IOM.The data presented in this study show that all aspects of the composition of organic matter in IDPs are affected by atmospheric entry heating. Modelling and temperature estimates from stepwise release of He has shown that most IDPs are heated to >500°C (Love and Brownlee, 1991;Nier and Schlutter, 1993;Joswiak et al., 2007), hence, atmospheric entry heating is expected to have altered the organic matter in most IDPs.

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“…The meteorites shown in Figure 2 are Ivuna (CI1), LaPaz Icefield (LAP) 02277 (CM1), Meteorite Hills (MET) 00639 (CM2), and Cold Bokkeveld (CM2) 19 . Cold Bokkeveld may have been very mildly and briefly heated based on Raman spectroscopy of the insoluble organic material, but the evidence is somewhat ambiguous 51,52 and there is no mineralogical evidence of heating that would change our interpretation of the observed 2.71-μm feature (where mineralogy is the property to which the laboratory and remote sensing measurements shown here are sensitive). Because meteorites have interacted with the Earth's environment, even if briefly, they are prone to mineralogical and chemical alteration, including the adsorption and absorption of terrestrial water (which can be recognized through oxygen isotope analysis).…”

Section: Meteorite Samplesmentioning

confidence: 77%

Evidence for widespread hydrated minerals on asteroid (101955) Bennu

Barucci¹,

Highsmith²,

Small³

et al. 2019

Nat Astron

286

205

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Prevalence and nature of heating processes in CM and C2-ungrouped chondrites as revealed by insoluble organic matter

Cited by 99 publications

References 71 publications

Comparison of FT‐IR spectra of bulk and acid insoluble organic matter in chondritic meteorites: An implication for missing carbon during demineralization

Comparison of FT‐IR spectra of bulk and acid insoluble organic matter in chondritic meteorites: An implication for missing carbon during demineralization

The effects of atmospheric entry heating on organic matter in interplanetary dust particles and micrometeorites

Evidence for widespread hydrated minerals on asteroid (101955) Bennu

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