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See detailCombined micro-Fourier transform infrared (FTIR) spectroscopy and micro-Raman spectroscopy of Proterozoic acritarchs: A new approach to Palaeobiology
Marshall, C. P.; Javaux, Emmanuelle ULg; Knoll, A. H. et al

in Precambrian Research (2005), 138(3-4), 208-224

Micro-scale analytical techniques permit correlation of chemistry with morphology of individual Proterozoic acritarchs (organic-walled microfossils), and thus provide new approaches for elucidating their ... [more ▼]

Micro-scale analytical techniques permit correlation of chemistry with morphology of individual Proterozoic acritarchs (organic-walled microfossils), and thus provide new approaches for elucidating their biological affinities. A combination of micro-Fourier transform infrared (FTIR) spectroscopy and laser micro-Raman spectroscopy was used to investigate the organic structure and composition of individual acritarchs. Well preserved Neoproterozoic acritarchs from the Tanana Formation, Australia (ca. 590-565 Ma), and Mesoproterozoic acritarchs from the Roper Group (1.5-1.4 Ga), Australia, and Ruyang Group, China (1.4-1.3 Ga, age poorly resolved but certainly > 1000 Ma and < 1625 Ma) have thermal maturities that range from immature to oil window. FTIR spectra of Tanarium conoideum from the Tanana Formation contain intense aliphatic C-H stretching bands in the 2900 cm(-1) region relative to the C=C aromatic ring stretching band at 1600 cm(-1). This FTIR spectrum is consistent with the FTIR spectra obtained from algaenans isolated from extant chlorophyte and eustigmatophyte microalgae. FTIR spectra of Leiosphaeridia sp. from the Tanana Formation contain a less intense aliphatic C-H stretching band relative to the C=C aromatic ring stretching band. By comparison, the spectra acquired from the Mesoproterozoic acritarchs were dominated by C=C aromatic ring stretching bands at 1600 cm(-1) relative to moderate-weak CH3 terminal groups (1345 cm(-1)), C-H aliphatic stretching (3000-2700 cm(-1)), and C=O (1710 cm-1), although some differences in biopolymer composition occurred between species. Curve-fitting of the aliphatic C-H, stretching region provides greater insight into the aliphatic structures of the acritarchs. The CH2/CH3 intensity ratio can be used to assess the relative chain length and degree of branching. Organic material in the Tanarium conoideum consists of straight long chain hydrocarbons, while the other acritarchs contain hydrocarbons consisting of short chains that are highly branched. In this study it was found that Raman spectroscopy does not provide additional information about biopolymer composition of Proterozoic acritarchs, but rather offers complementary data regarding the aromaticity and degree of saturation of the macromolecular structure of acritarch cysts. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailTEM evidence for eukaryotic diversity in mid-Proterozoic oceans
Javaux, Emmanuelle ULg; Knoll, A. H.; Walter, Malcolm

in Geobiology (2004), 2

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See detailEarly eukaryotes in Paleoproterozoic and Mesoproterozoic oceans
Javaux, Emmanuelle ULg; Marshall, C.; Xiao, S. et al

Poster (2004)

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See detailExtremophiles, early Earth biosphere and exobiology
Javaux, Emmanuelle ULg; Marshall, C.

Poster (2004)

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See detailProtistan evolution in the Precambrian: a new multidisciplinary approach combining microscopy and microchemistry
Javaux, Emmanuelle ULg; Marchall, C. P.; Knoll, A. H. et al

Conference (2004)

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See detailEvolution de la biosphère au Précambrien
Javaux, Emmanuelle ULg

Scientific conference (2004)

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See detailA la recherche de la vie dans le système solaire
Javaux, Emmanuelle ULg

Article for general public (2004)

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See detailEvolution des eucaryotes au Précambrien
Javaux, Emmanuelle ULg

Scientific conference (2004)

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See detailA la recherche de la vie dans l’univers
Javaux, Emmanuelle ULg

Article for general public (2004)

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See detailThe hunt for early eukaryotes in Archean and Proterozoic oceans
Javaux, Emmanuelle ULg; Knoll, A. H.; Marshall, C. P. et al

Poster (2003)

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See detailILLUSTRATION OF MODERN BENTHIC FORAMINIFERA FROMBERMUDA AND REMARKS ON DISTRIBUTION IN OTHER SUBTROPICAL/TROPICAL AREAS
Javaux, Emmanuelle ULg; Scott, David

in Palaeontologia Electronica (2003), 6(4), 1-29

A scanning light microscope (SLM) is used to illustrate recent benthic foraminiferal species from surface sediment samples collected in Bermuda subtropical environments. Species illustrated here are the ... [more ▼]

A scanning light microscope (SLM) is used to illustrate recent benthic foraminiferal species from surface sediment samples collected in Bermuda subtropical environments. Species illustrated here are the main foraminiferal species found in Bermuda lagoons, reefs, caves, mangroves, and ponds, but also occur in most subtropical and tropical areas. The SLM permits photography of specimens without coating and gives pictures most similar to specimens that micropaleontologists see under a dissecting reflected light microscope in a petri dish with water, in contrast to images made with scanning electron microscopes. These pictures are the first SLM illustrations of subtropical/tropical species of benthic foraminifera and will be very useful for their identification. Bermuda recent sediment hosts a benthic foraminifera fauna as diverse as in other subtropical and tropical areas, and the general trends of foraminiferal distribution and morphology are similar. Remarks on foraminiferal distribution in Bermuda and other subtropical/tropical areas are also presented. [less ▲]

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See detailRecognizing and interpreting the fossils of early eukaryotes
Javaux, Emmanuelle ULg; Knoll, A. H.; Walter, M.

in Origins of Life & Evolution of the Biosphere (2003), 33(1), 75-94

Using molecular sequence data, biologists can generate hypotheses of protistan phylogeny and divergence times. Fossils, however, provide our only direct constraints on the timing and environmental context ... [more ▼]

Using molecular sequence data, biologists can generate hypotheses of protistan phylogeny and divergence times. Fossils, however, provide our only direct constraints on the timing and environmental context of early eukaryotic diversification. For this reason, recognition of eukaryotic fossils in Proterozoic rocks is key to the integration of geological and comparative biological perspectives on protistan evolution. Microfossils preserved in shales of the ca. 1500 Ma Roper Group, northern Australia, display characters that ally them to the Eucarya, but, at present, attribution to any particular protistan clade is uncertain. Continuing research on wall ultrastructure and microchemistry promises new insights into the nature and systematic relationships of early eukaryotic fossils. [less ▲]

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See detailL’astrobiologie
Javaux, Emmanuelle ULg

Scientific conference (2003)

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See detailDiversity and complexity of Early Eukaryotic cells
Javaux, Emmanuelle ULg; Knoll, A. H.; Walter, M.

Conference (2003)

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See detailRecognizing and interpreting the fossils of early eukaryotes.
Javaux, Emmanuelle ULg; Knoll, Andrew H; Walter, Malcolm

Conference (2002, October)

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See detailEarly eukaryotic diversification
Javaux, Emmanuelle ULg; knoll, A. H.; Walter, M.

Conference (2002)

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See detailCytological and ecological complexity in the Early Mesoproterozoic.
Javaux, Emmanuelle ULg; Knoll, A. H.; Walter, M.

Conference (2001, November)

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See detailComplex protists in Mesoproterozoic rocks.
Javaux, Emmanuelle ULg; knoll, A. H.; Walter, M.

Conference (2001, April)

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