Raman microspectrometry of accumulated non-graphitized solid bitumens

Jehlička, Jan; Beny, C.; Rouzaud, Jean-Noël

doi:10.1002/(sici)1097-4555(199709)28:9<717::aid-jrs168>3.0.co;2-7

Cited by 35 publications

(6 citation statements)

References 9 publications

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“…Highly carbonized hard solid bitumens from basaltic rocks, which cross-cut a black shale formation of Upper Proterozoic age in central and western part of the Bohemian Massif, Czech Republic, are characterized by a low atomic H / C ratio of about 0.1. They differ from dispersed kerogens isolated from regionally metamorphosed black shales of the same primary sedimentary basin (Jehlicka, 1994;Jehlicka et al, 1997Jehlicka et al, , 2003.…”

Section: Sample Setmentioning

confidence: 94%

Nitrogen isotopic evolution of carbonaceous matter during metamorphism: Methodology and preliminary results

Ader¹,

Cartigny²,

Boudou³

et al. 2006

Chemical Geology

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Nitrogen content and isotopic composition of carbonaceous-rich metasediments were determined by on-line and sealed-tube combustion using ultra-high vacuum line and static mass spectrometer adapted to analyse nitrogen nanomoles. Accurate measurements showed that nitrogen amount released by on-line combustion technique was underestimated to various extents. As a result, the nitrogen isotopic composition was not correctly determined. In contrast, sealed-tube combustion appeared to yield the most reproducible and accurate measurements, except for nitrogen depleted carbonaceous matter (semi-graphite to graphite transition) containing less than around 60 ppm of nitrogen, which were contaminated during their extraction from the rock. In view of that, a preliminary sealed-tube investigation of the organic nitrogen content and isotopic composition in a homogenous series of low-grade metasediments was undertaken: in spite of an important nitrogen loss, the carbonaceous matter nitrogen isotopic composition remains about the same during the meta-anthracite and semi-graphitisation stages. Inferences on the process of organic nitrogen mineralization during carbonaceous matter metamorphism can be drawn and several paleo-biogeochemical implications envisaged

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Section: Sample Setmentioning

confidence: 94%

Nitrogen isotopic evolution of carbonaceous matter during metamorphism: Methodology and preliminary results

Ader¹,

Cartigny²,

Boudou³

et al. 2006

Chemical Geology

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“…Raman spectroscopy is an effective tool for assessing the degree of crystallinity in carbonaceous materials-notably of extracted kerogens such as those reported herein-as poorly ordered kerogen and well-ordered graphite produce differing Raman shifts (Pasteris & Wopenka, 1991Jehlička & Bény, 1992Wopenka & Pasteris, 1993;Yui et al, 1996;Jehlička et al, 1997Jehlička et al, , 2003Spotl et al, 1998;Nestler et al, 2003;Marshall et al, 2010). Further, the degree of crystallinity of carbonaceous material has been shown to correlate strongly with the peak metamorphic temperature that it experienced (Grew, 1974;Pasteris & Wopenka, 1991;Wopenka & Pasteris, 1993;Beyssac et al, 2002aBeyssac et al, , 2003.…”

Section: Raman Spectroscopymentioning

confidence: 99%

Thermally‐induced structural and chemical alteration of organic‐walled microfossils: an experimental approach to understanding fossil preservation in metasediments

Schiffbauer¹,

Wallace²,

Hunter³

et al. 2012

Geobiology

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The identification and confirmation of bona fide Archean-Paleoproterozoic microfossils can prove to be a challenging task, further compounded by diagenetic and metamorphic histories. While structures of likely biological origin are not uncommon in Precambrian rocks, the search for early fossil life has been disproportionately focused on lesser thermally altered rocks, typically greenschist or lower-grade metamorphism. Recently, however, an increasing number of inferred micro- and macrofossils have been reported from higher-grade metasediments, prompting us to experimentally test and quantify the preservability of organic-walled microfossils over varying durations of controlled heating and under two differing redox conditions. Because of their relatively low-intensity natural thermal alteration, acritarchs from the Mesoproterozoic Ruyang Group were chosen as subjects for experimental heating at approximately 500°C, with durations ranging from 1 to 250 days and in both oxic (normal present day conditions) and anoxic conditions. Upon extraction, the opacity, reflectivity, color, microchemistry, and microstructures of the heated acritarchs were characterized using optic microscopy, scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The results differ for acritarchs prepared under oxic vs. anoxic conditions, with the anoxic replicates surviving experimental heating longer and retaining biological morphologies better, despite an increasing degree of carbonization with continuous heating. Conversely, the oxic replicates show aggressive degradation. In conjunction with fossils from high-grade metasediments, our data illustrate the preservational potential of organic-walled microfossils subjected to metamorphism in reducing conditions, offer insights into the search for microfossils in metasediments, and help to elucidate the influence of time on the carbonization/graphitization processes during thermal alteration.

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“…In recent years, a series of papers on Raman and micro-Raman spectroscopy applications were published in order to characterize the molecular structure of fossil resins, allowing nondestructive and rapid interpretation of geological origin of the samples investigated. 8–26…”

Section: Introductionmentioning

confidence: 99%

Fourier Transform Raman and Statistical Analysis of Thermally Altered Samples of Amber

et al. 2015

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We report the experimental results that refer to a Fourier transform Raman (FT-Raman) survey of thermally altered Baltic and Romanian amber and the related statistical interpretation of data using principal component analysis (PCA). Although FT-Raman spectra show several small changes in the characteristic features of the investigated amber samples which may be used for discrimination, their visual recognition is relatively difficult, especially when interpreting data from archeological samples, and thus multivariate data analysis may be the solution to more accurately assign the geological origin based on overall characteristic spectral features. The two categories of amber have different behavior in terms of degradation during the experimental alteration, and Romanian amber is more susceptible to physico-chemical transformations by the aggressive environment when compared with Baltic amber. The obtained data were in accordance with the Fourier transform infrared (FT-IR) remarks published previously in a dedicated journal. The Raman technique is an alternative method that requires little to no sample preparation, water does not cause interference, and the spectra can be collected from a small volume (1-50 μm in diameter).

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Raman microspectrometry of accumulated non-graphitized solid bitumens

Cited by 35 publications

References 9 publications

Nitrogen isotopic evolution of carbonaceous matter during metamorphism: Methodology and preliminary results

Nitrogen isotopic evolution of carbonaceous matter during metamorphism: Methodology and preliminary results

Thermally‐induced structural and chemical alteration of organic‐walled microfossils: an experimental approach to understanding fossil preservation in metasediments

Fourier Transform Raman and Statistical Analysis of Thermally Altered Samples of Amber

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