EPR study of kerogens from Middle Valley, Northern Juan de Fuca Ridge (ODP Leg 139)

Dickneider, Trudy A.; Scull, Stephanie; Whelan, Jean K.; Blough, Neil V.

doi:10.1016/s0146-6380(97)00010-7

Cited by 7 publications

(3 citation statements)

References 14 publications

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“…These types of radicals were therefore used for the characterization of a wide range of carbonaceous materials, ranging from coals (Retcofsky et al, 1968;Mrozowski, 1988aMrozowski, , 1988b to cherts (Skrzypczak-Bonduelle et al, 2008) or meteorites (Binet et al, 2002(Binet et al, , 2004Gourier et al, 2008;Delpoux et al, 2011). The EPR signal of kerogen has the form of a single line, which reflects the presence of aromatic radical moieties with an unpaired electron spin delocalized in pp-type molecular orbitals (Uebersfeld et al, 1954;Retcofsky et al, 1968;Mrozowski, 1988b;Dickneider et al, 1997). Several parameters can be deduced from the EPR spectra based on the amplitude, the linewidth, and the resonance field of the signal.…”

Section: Introductionmentioning

confidence: 99%

Dating Carbonaceous Matter in Archean Cherts by Electron Paramagnetic Resonance

Bourbin¹,

Gourier

Derenne³

et al. 2013

Astrobiology

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Ancient geological materials are likely to be contaminated through geological times. Thus, establishing the syngeneity of the organic matter embedded in a mineral matrix is a crucial step in the study of very ancient rocks. This is particularly the case for Archean siliceous sedimentary rocks (cherts), which record the earliest traces of life. We used electron paramagnetic resonance (EPR) for assessing the syngeneity of organic matter in cherts that have a metamorphic grade no higher than greenschist. A correlation between the age of Precambrian samples and the shape of their EPR signal was established and statistically tested. As thermal treatments impact organic matter maturity, the effect of temperature on this syngeneity proxy was studied; cyanobacteria were submitted to cumulative short thermal treatment at high temperatures followed by an analysis of their EPR parameters. The resulting carbonaceous matter showed an evolution similar to that of a thermally treated young chert. Furthermore, the possible effect of metamorphism, which is a longer thermal event at lower temperatures, was ruled out for cherts older than 2 Gyr, based on the study of Silurian cherts of the same age and same precursors but various metamorphic grades. We determined that even the most metamorphosed sample did not exhibit the lineshape of an Archean sample. In the hope of detecting organic contamination in Archean cherts, a "contamination-like" mixture was prepared and studied by EPR. It resulted that the lineshape analysis alone does not allow contamination detection and that it must be performed along with cumulative thermal treatments. Such treatments were applied to three Archean chert samples, making dating of their carbonaceous matter possible. We concluded that EPR is a powerful tool to study primitive organic matter and could be used in further exobiology studies on low-metamorphic grade samples (from Mars for example).

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Section: Introductionmentioning

confidence: 99%

Dating Carbonaceous Matter in Archean Cherts by Electron Paramagnetic Resonance

Bourbin¹,

Gourier

Derenne³

et al. 2013

Astrobiology

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“…EPR associated with carbonaceous matter (IOM) have long been studied, for example in ancient carbonaceous material such as coal (Uebersfeld and Erb 1956;Retcofsky et al 1968;Mrozowski 1988a and1988b), carbonaceous cherts (Skrzypczak-Bonduelle et al 2008;Bourbin et al 2013), and carbonaceous chondrites (Duchesne et al 1964;Vinogradov et al 1964;Schulz and Elofson 1965;Binet et al 2002;2004;Gourier et al 2008;Delpoux et al 2011). These carbonaceous materials invariably give a single EPR line due to aromatic radical moieties with an unpaired electron spin delocalized in -type molecular orbitals (Uebersfeld et al 1954;Retcofsky et al 1968;Mrozowski 1988b;Dickneider et al 1997). The IOM line can be characterized by its intensity (proportional to the number of radicals), its g-factor (measured from the magnetic field at resonance) and its lineshape.…”

Section: Epr Lineshape Analysis Of Carbonaceous Mattermentioning

confidence: 99%

Extraterrestrial organic matter preserved in 3.33 Ga sediments from Barberton, South Africa

Gourier

Binet

Calligaro

et al. 2019

Geochimica et Cosmochimica Acta

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Electron paramagnetic resonance (EPR) analysis of carbonaceous, volcanic, tidal sediments from the 3.33 Ga-old Josefsdal Chert (Kromberg Formation, Barberton Greenstone Belt), documents the presence of two types of insoluble organic matter (IOM): (1) IOM similar to that previously found in Archean cherts from numerous other sedimentary rocks in the world and of purported biogenic origin; (2) anomalous IOM localized in a 2 mm-thick sedimentary horizon. Detailed analysis by continuous-wave-EPR and pulse-EPR reveals that IOM in this layer is similar to the insoluble component of the hydrogenated organic matter in carbonaceous chondrites, suggesting that this narrow sedimentary horizon has preserved organic matter of extraterrestrial origin. This conclusion is supported by the presence in this thin layer of another anomalous EPR signal at g = 3 attributed to Ni-Cr-Al ferrite spinel nanoparticles, which are known to form during atmospheric entry of cosmic objects. From this EPR analysis, it was deduced that the anomalous sedimentary layer originates from 2 deposition, in a nearshore environment, of a cloud of tiny dust particles originating from a flux of micrometeorites falling through the oxygen-poor Archean atmosphere.

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“…These types of radicals were therefore used for the characterization of a wide range of carbonaceous objects, ranging from coals [ 4 - 6 ] to cherts [ 7 ] through meteorites [ 8 - 11 ]. The EPR signal of kerogen is a single line, due to the presence of aromatic radical moieties, with an unpaired electron spin delocalized in carbon p-type molecular orbitals [ 4 , 9 , 12 , 13 ]. Several parameters can be deduced from an EPR spectrum, based on the amplitude A pp , the linewidth Δ B pp and the resonance field B res of the signal.…”

Section: Background: Necessity For a Shape Factor Definitionmentioning

confidence: 99%

Implementing a new EPR lineshape parameter for organic radicals in carbonaceous matter

Bourbin¹,

Binet

et al. 2013

Source Code Biol Med

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BackgroundElectron Paramagnetic Resonance (EPR) is a non-destructive, non-invasive technique useful for the characterization of organic moieties in primitive carbonaceous matter related to the origin of life. The classical EPR parameters are the peak-to-peak amplitude, the linewidth and the g factor; however, such parameters turn out not to suffice to fully determine a single EPR line.ResultsIn this paper, we give the definition and practical implementation of a new EPR parameter based on the signal shape that we call the R10 factor. This parameter was originally defined in the case of a single symmetric EPR line and used as a new datation method for organic matter in the field of exobiology.ConclusionCombined to classical EPR parameters, the proposed shape parameter provides a full description of an EPR spectrum and opens the way to novel applications like datation. Such a parameter is a powerful tool for future EPR studies, not only of carbonaceous matter, but also of any substance which spectrum exhibits a single symmetric line.ReproducibilityThe paper is a literate program—written using Noweb within the Org-mode as provided by the Emacs editor— and it also describes the full data analysis pipeline that computes the R10 on a real EPR spectrum.

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EPR study of kerogens from Middle Valley, Northern Juan de Fuca Ridge (ODP Leg 139)

Cited by 7 publications

References 14 publications

Dating Carbonaceous Matter in Archean Cherts by Electron Paramagnetic Resonance

Dating Carbonaceous Matter in Archean Cherts by Electron Paramagnetic Resonance

Extraterrestrial organic matter preserved in 3.33 Ga sediments from Barberton, South Africa

Implementing a new EPR lineshape parameter for organic radicals in carbonaceous matter

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EPR study of kerogens from Middle Valley, Northern Juan de Fuca Ridge (ODP Leg 139)

Cited by 7 publications

References 14 publications

Dating Carbonaceous Matter in Archean Cherts by Electron Paramagnetic Resonance

Dating Carbonaceous Matter in Archean Cherts by Electron Paramagnetic Resonance

Extraterrestrial organic matter preserved in 3.33 Ga sediments from Barberton, South Africa

Implementing a new EPR lineshape parameter for organic radicals in carbonaceous matter

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Extraterrestrial organic matter preserved in 3.33 Ga sediments from Barberton, South Africa