Texture-specific isotopic compositions in 3.4Gyr old organic matter support selective preservation in cell-like structures

Lepot, Kevin; Williford, Kenneth H.; Ushikubo, T.; Sugitani, Kenichiro; Mimura, Koichi; Spicuzza, Michael J.; Valley, John W.

doi:10.1016/j.gca.2013.03.004

Cited by 89 publications

(91 citation statements)

References 84 publications

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“…1j). Application of the RSCM (Raman Spectroscopy of Carbonaceous Material) geothermometer (Beyssac et al, 2002;Lahfid et al, 2010) indicates that the Strelley Pool microfossils experienced peak temperatures of approximately 300 °C, which is in good agreement with regional metamorphic histories (Wacey et al, 2011a;Lepot et al, 2013;Sugitani et al, 2013). Transmission electron microscopy conducted on FIB foils demonstrates that, even at the nanometre scale, the organic matter is intimately associated with quartz and clays, as well as crystalline chlorides or sulphate minerals (Fig.…”

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confidence: 55%

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Chemical nature of the 3.4 Ga Strelley Pool microfossils

Alleon¹,

Bernard²,

Guillou³

et al. 2018

Geochem. Persp. Let.

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mentioning

confidence: 55%

“…These cherts are thought to have formed through the crystallisation of colloidal silica that was deposited in a shallow water marine environment, with some hydrothermal inputs . Since their formation, these cherts have only undergone low grade metamorphism (prehnite-pumpellyite to lower greenschist facies; Lepot et al, 2013;Sugitani et al, 2013).…”

mentioning

confidence: 99%

Chemical nature of the 3.4 Ga Strelley Pool microfossils

Alleon¹,

Bernard²,

Guillou³

et al. 2018

Geochem. Persp. Let.

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“…Biological interpretations of Archean microstructures find support in NanoSIMS analyses, which show consistent elemental and C-isotopic abundances within morphological classes, but differences among them Lepot et al 2013). Also, a few early Archean populations show evidence of binary division and/or differentiated internal contents (Knoll and Barghoorn 1977;Sugitani et al 2009b).…”

Section: Problems Of Archean Paleobiologymentioning

confidence: 93%

Paleobiological Perspectives on Early Microbial Evolution

Knoll

2015

Cold Spring Harb Perspect Biol

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Microfossils, stromatolites, and chemical biosignatures indicate that Earth became a biological planet more than 3.5 billion years ago, making most of life's history microbial. Proterozoic rocks preserve a rich record of cyanobacteria, including derived forms that differentiate multiple cell types. Stromatolites, in turn, show that microbial communities covered the seafloor from tidal flats to the base of the photic zone. The Archean record is more challenging to interpret, particularly on the question of cyanobacterial antiquity, which remains to be resolved. In the late Neoproterozoic Era, increasing oxygen and radiating eukaryotes altered the biosphere, with planktonic algae gaining ecological prominence in the water column, whereas seaweeds and, eventually, animals spread across shallow seafloors. From a microbial perspective, however, animals, algae, and, later, plants simply provided new opportunities for diversification, and, to this day, microbial metabolisms remain the only essential components of biogeochemical cycles.

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“…Schidlowski, 2001). Recent technological advances have made it possible to measure in-situ carbon isotopic compositions of individual microfossils using secondary ion mass spectrometry (SIMS), which enables direct correlation between fossil morphologies and isotopic compositions, and this approach has been particularly insightful for studying Precambrian microfossils and metabolic pathways (Kaufman and Xiao, 2003;Williford et al, 2013;Lepot et al, 2013;House et al, 2013).…”

Section: Secondary Ion Mass Spectrometry (Sims)mentioning

confidence: 99%

Carbonaceous biosignatures of diverse chemotrophic microbial communities from chert nodules of the Ediacaran Doushantuo Formation

Wang

Xiao

Whitehouse

et al. 2017

Precambrian Research

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a b s t r a c tThe Ediacaran Doushantuo Formation (DST) is renowned for exceptionally preserved Precambrian fossils including metazoans. Some of these fossils, particularly microfossils such as multicellular algae and acanthomorphic acritarchs, are preserved in DST chert nodules. To better understand the geomicrobiological processes that contributed to the authigenic formation of DST chert nodules and facilitated exceptional fossil preservation, we analyzed organic matter in these chert nodules and the surrounding matrix (calcareous mudstone) using multiple in-situ techniques: confocal laser Raman spectroscopy, micro-Fourier transform infrared spectroscopy (FTIR), and secondary ion mass spectroscopy (SIMS). We found strong ultrastructural, chemical, and isotopic heterogeneities in the organic matter as indicated by the Raman spectral parameter I-1350/1600 ranging from 0.49 to 0.88, the infrared spectral index R 3/2 from 0.12 to 0.90, and an estimated d13C org-SIMS range of 44‰ (V-PDB). These micron-scale heterogeneities imply that the organic matter preserved in the DST chert nodules is derived from different carbonaceous sources in a diverse microbial ecosystem, including eukaryotic and/or prokaryotic photoautotrophs, as well as chemotrophs involved in the fermentation and probably anaerobic oxidation of organic remains. Thus, the microbial ecosystems in Ediacaran ocean waters and sediments were more complex than previously thought, and these microbial processes controlled dynamic micro-environments in DST sediments where chert nodules were formed and fossils were mineralized. The results also show that variations in the relative abundances, activities, and interactions of co-existing microorganisms in DST sediments may have modulated d13C org shifts, causing local decoupling between d13C org and d13C carb as measured in bulk samples.

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Texture-specific isotopic compositions in 3.4Gyr old organic matter support selective preservation in cell-like structures

Cited by 89 publications

References 84 publications

Chemical nature of the 3.4 Ga Strelley Pool microfossils

Chemical nature of the 3.4 Ga Strelley Pool microfossils

Paleobiological Perspectives on Early Microbial Evolution

Carbonaceous biosignatures of diverse chemotrophic microbial communities from chert nodules of the Ediacaran Doushantuo Formation

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