References of "Beghin, Jérémie"
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See detailReconstructing Early Atlantic to Early Subatlantic peat-forming conditions of the ombrotrophic Misten Bog (eastern Belgium) on the basis of high-resolution analyses of pollen, testate amoebae and geochemistry
Streel, Maurice ULiege; Paillet, Marc ULiege; Beghin, Jérémie ULiege et al

in Geologica Belgica (2018), 21(3-4),

A seven metres thick peat bog (Misten, Hautes-Fagnes, Belgium) has been studied at high resolution in order to reconstruct the conditions of peat formation and evolution on the basis of pollen, testate ... [more ▼]

A seven metres thick peat bog (Misten, Hautes-Fagnes, Belgium) has been studied at high resolution in order to reconstruct the conditions of peat formation and evolution on the basis of pollen, testate amoebae analysis, and geochemistry. The sampled section of the peat bog corresponds to the most part of the Atlantic period, all the Subboreal period and the earliest Subatlantic period, i.e. a time interval between 7300 cal BP and 2000 cal BP. The identification of tie-points in the pollen assemblages recognized in a previous work (Persch, 1950) performed in the periphery of the same peat-bog, allows accurate correlation of the two sites, 460 cm thickness of peat in the central part corresponding to 230 cm thickness of peat in the periphery. The well constrained dates of the tie-points in the present work provide a more precise chronology of the events identified in Persch’s pollen diagram. A comparison of pollen data in both sites demonstrates that, as expected, the Corylus pollen rain is proportionally more important and the Quercetum mixtum pollen rain proportionally less important in the central area of the peat bog than in the periphery. The study of the testate amoebae in the central part of the peat bog is the major contribution of the present work. A stratigraphically constrained analysis resulted in the identification of five biozones, the zonation being mainly built on the fluctuations observed between Archerella (Amphitrema) flavum and Difflugia pulex. Three transfer functions have been applied and compared. Coupled with the humification values of each level, it allows a very accurate approach of the water-table level, and hence of local climatic conditions, at the time of the peat formation. Combination of pollen results and testate amoebae zonal subdivisions allows the definition, dating and interpretation of 18 rather short time intervals with an approximate duration of 200 to 300 years each. Our results validate and expand a previously published climate interpretation that combined geochemical data and a preliminary testate amoebae analysis. [less ▲]

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See detail1.1 billion years old porphyrins and their isotopic composition establish a marine ecosystem dominated by bacterial primary producers
Gueneli, Nur; McKenna, AC; Ohkouchi et al

in Proceedings of the National Academy of Sciences of the United States of America (2018)

The average cell size of marine phytoplankton is critical for the flow of energy and nutrients from the base of the food web to higher trophic levels. Thus, the evolutionary succession of primary ... [more ▼]

The average cell size of marine phytoplankton is critical for the flow of energy and nutrients from the base of the food web to higher trophic levels. Thus, the evolutionary succession of primary producers through Earth’s history is important for our understanding of the radiation of modern protists ∼800 million years ago and the emergence of eumetazoan animals ∼200 million years later. Currently, it is difficult to establish connections between primary production and the proliferation of large and complex organisms because the mid-Proterozoic (∼1,800–800 million years ago) rock record is nearly devoid of recognizable phytoplankton fossils. We report the discovery of intact porphyrins, the molecular fossils of chlorophylls, from 1,100-million-year-old marine black shales of the Taoudeni Basin (Mauritania), 600 million years older than previous findings. The porphyrin nitrogen isotopes (δ15Npor = 5.6–10.2‰) are heavier than in younger sedimentary sequences, and the isotopic offset between sedimentary bulk nitrogen and porphyrins (εpor = −5.1 to −0.5‰) points to cyanobacteria as dominant primary producers. Based on fossil carotenoids, anoxygenic green (Chlorobiacea) and purple sulfur bacteria (Chromatiaceae) also contributed to photosynthate. The low εpor values, in combination with a lack of diagnostic eukaryotic steranes in the time interval of 1,600–1,000 million years ago, demonstrate that algae played an insignificant role in mid-Proterozoic oceans. The paucity of algae and the small cell size of bacterial phytoplankton may have curtailed the flow of energy to higher trophic levels, potentially contributing to a diminished evolutionary pace toward complex eukaryotic ecosystems and large and active organisms. [less ▲]

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See detailEarly eukaryotes: insights from microanalyses of proterozoic microfossils
Cornet, Yohan ULiege; Beghin, Jérémie ULiege; Kabamba Baludikay, Blaise ULiege et al

in Goldschmidt Abstracts, 2017 (2017, August)

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See detailA palaeoecological model for the late Mesoproterozoic–early Neoproterozoic Atar/El Mreïti Group, Taoudeni Basin, Mauritania, northwestern Africa
Beghin, Jérémie ULiege; Guilbaud, Romain; Poulton, Simon W. et al

in Precambrian Research (2017), 299

Reconstructing the spatial distribution of early eukaryotes in palaeoenvironments through Proterozoic sedimentary basins provides important information about their palaeoecology and taphonomic conditions ... [more ▼]

Reconstructing the spatial distribution of early eukaryotes in palaeoenvironments through Proterozoic sedimentary basins provides important information about their palaeoecology and taphonomic conditions. Here, we combine the geological context and a reconstruction of palaeoenvironmental redox conditions (using iron speciation) with quantitative analysis of microfossil assemblages (eukaryotes andincertae sedis), to provide the first palaeoecological model for the Atar/El Mreïti Group of the Taoudeni Basin. Our model suggests that in the late Mesoproterozoic–early Neoproterozoic, the availability of both molecular oxygen and nutrients controlled eukaryotic diversity, higher in oxic shallow marginal marine environments, while coccoidal colonies and benthic microbial mats dominated respectively in anoxic iron-rich and euxinic waters during marine highstands or away from shore where eukaryotes are lower or absent. [less ▲]

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See detailMicrofossils from the late Mesoproterozoic – early Neoproterozoic Atar/El Mreïti Group, Taoudeni Basin, Mauritania, northwestern Africa
Beghin, Jérémie ULiege; Storme, Jean-Yves; Blanpied, Christian et al

in Precambrian Research (2017), 291

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See detailPLANET TOPERS: Planets, Tracing the Transfer, Origin, Preservation, and Evolution of their ReservoirS
Dehant, Véronique ULiege; Kabamba Baludikay, Blaise ULiege; Beghin, Jérémie ULiege et al

in Origins of Life and Evolution of the Biosphere (2016), DOI 10.1007/s11084-016-9488

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See detailMicroanalyzes of remarkable microfossils of the Late Mesoproterozoic–Early Neoproterozoic
Cornet, Yohan ULiege; Beghin, Jérémie ULiege; Kabamba Baludikay, Blaise ULiege et al

in European Geosciences Union General Assembly 2016 Vienna, Austria, 2016 (2016)

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See detailTowards a palaeoecological model of the Mesoproterozoic Taoudeni basin
Beghin, Jérémie ULiege; Poulton, Simon; Gueneli, Nur et al

Conference (2015)

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See detailBIODIVERSITY AND REDOX CONDITIONS THROUGH THE PROTEROZOIC TAOUDENI BASIN OF MAURITANIA
Beghin, Jérémie ULiege; Poulton, Simon; Gueneli, Nur et al

Scientific conference (2014, November 03)

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See detailBIODIVERSITY AND REDOX CONDITIONS THROUGH THE PROTEROZOIC TAOUDENI BASIN OF MAURITANIA
Beghin, Jérémie ULiege; Poulton, Simon; Gueneli, Nur et al

Conference (2014, September)

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See detailMicrofossils’ diversity from the Proterozoic Taoudeni Basin, Mauritania
Beghin, Jérémie ULiege; Javaux, Emmanuelle ULiege; Houzay, Jean-Pierre et al

in European Geosciences Union General Assembly 2014 Vienna, Austria, 27 April – 02 May 2014 (abstract book) (2014, April 27)

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See detailHolocene dust record in a NW European peat bog: A multiproxy approach
Allan, Mohammed ULiege; Le Roux, Gael; Verheyden, Sophie et al

Conference (2013, August 28)

Dust deposition in southern Belgium is estimated from the geochemical signature of an ombrotrophic bog. The analyses of Rare Earth Elements (REE) and lithogenic element concentrations as well as Nd ... [more ▼]

Dust deposition in southern Belgium is estimated from the geochemical signature of an ombrotrophic bog. The analyses of Rare Earth Elements (REE) and lithogenic element concentrations as well as Nd isotopes were performed by HR-ICP-MS and MC-ICP-MS respectively, in a  6 m peat section representing 5300 years, from 30 BC to 5300 BC dated by the 14C method. REE concentration variations in peat samples were used as a dust proxy and the Nd isotopes to trace the sources. Peat humification and testate amoebae were used to evaluate hydroclimatic conditions. The range of dust deposition varied from 0.03 to 4 g m-2 yr-1. The highest dust fluxes were observed from 800 to 600 BC, and from 3200 to 2800 BC and correspond to cold periods. The Nd values show large variability, between -5 and –13, identifying three major sources of dust: local soils, distal volcanic and desert particles. By comparing our results with the dust recorded in other peat bogs and ice cores from different latitudes, we evidence that the Misten peat is a valid archive for dust deposition. [less ▲]

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