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| Hillaire-marcel, C.; De Vernal, Anne; Piper, David J. W.. |
| The 8.2 ka "climate'' event recorded in Greenland ice cores is subject of debates with respect to causal linkage with a collapse of the Atlantic Meridional Overturning due to the drainage of the late-glacial lake Agassiz. Here, we present records from the NW North Atlantic, down-current the flood discharge route, showing that the 9.5-8 ka interval was marked by a succession of events. The drainage itself corresponds to a twin-layer of carbonate-rich turbidites deposited within the calibrated 8.35-8.5 ka interval. Proxies of sea-surface and deep-current conditions do not indicate significant concomitant changes in the NW North Atlantic. The dataset,however, supports the concept that the 8.2 ka "climate'' event may represent one of the manifestations of... |
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| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00235/34645/33006.pdf |
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| Thibodeau, Benoit; De Vernal, Anne; Hillaire-marcel, Claude; Mucci, Alfonso. |
| The impact of human activities on Earth's climate is still subject to debate and the pattern of a sharp recent global temperature increase contrasting with much lesser variable temperatures during preceding centuries has often been challenged, partly due to the lack of unquestionable evidence. In this paper, oxygen isotope compositions of benthic foraminifer shells recovered from sediments of the Lower St. Lawrence Estuary and the Gulf are used to reconstruct temperature changes in a water mass originating from similar to 400 m deep North Atlantic waters. The data demonstrate that the 1.7 +/- 0.3 degrees C warming measured during the last century corresponds to a delta(18)O shift of 0.4 +/- 0.05 parts per thousand, encompassing the temperature effect and... |
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| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00231/34176/32910.pdf |
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| Van Nieuwenhove, Nicolas; Head, Martin J.; Limoges, Audrey; Pospelova, Vera; Mertens, Kenneth; Matthiessen, Jens; De Schepper, Stijn; De Vernal, Anne; Eynaud, Frédérique; Londeix, Laurent; Marret, Fabienne; Penaud, Aurélie; Radi, Taoufik; Rochon, André. |
| Organic-walled resting cysts of planktonic dinoflagellates occur commonly in modern marine sediment where they represent, with rare exceptions, the only geologically preservable part of the life cycle. Although many species do not produce fossilizable resting cysts, upper Quaternary sediments contain a diverse cyst record that is used frequently for paleoenvironmental reconstruction and stratigraphic analysis. Reconstructions of past sea-surface conditions rely on an understanding of the distributions of dinoflagellate cysts in modern sediments linked to their respective environmental parameters, underpinned by sound taxonomy and standardized nomenclature. Stratigraphic studies additionally require knowledge of morphological details to distinguish extant... |
| Tipo: Text |
Palavras-chave: Dinoflagellate cysts; Marine; Quaternary; Gymnodiniales; Gonyaulacales; Peridiniales. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00606/71817/70324.pdf |
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| Mertens, Kenneth; Van Nieuwenhove, Nicolas; Gurdebeke, Pieter R.; Aydin, Hilal; Bogus, Kara; Bringue, Manuel; Dale, Barrie; De Schepper, Stijn; De Vernal, Anne; Ellegaard, Marianne; Grothe, Arjen; Gu, Haifeng; Head, Martin J.; Heikkila, Maija; Limoges, Audrey; Londeix, Laurent; Louwye, Stephen; Marret, Fabienne; Masure, Edwige; Matsuoka, Kazumi; Mudie, Peta J.; Penaud, Aurelie; Pospelova, Vera; Price, Andrea Michelle; Ribeiro, Sofia; Rochon, Andre; Sangiorgi, Francesca; Schreck, Michael; Torres, Vladimir; Uzar, Serdar; Versteegh, Gerard J. M.; Warny, Sophie; Zonneveld, Karin. |
| We present a summary of two round-table discussions held during two subsequent workshops in Montreal (Canada) on 16 April 2014 and Ostend (Belgium) on 8 July 2015. Five species of the genus Achomosphaera Evitt 1963 and 33 of the genus Spiniferites Mantell 1850 emend. Sarjeant 1970 occuring in Pliocene to modern sediments are listed and briefly described along with remarks made by workshop participants. In addition, several holotypes and topotypes are reillustrated. Three species previously assigned to Spiniferites are here considered/accepted as belonging to other genera: Impagidinium inaequalis (Wall and Dale in Wall et al. 1973) Londeix et al. 2009, Spiniferites? rubinus (Rossignol 1962 ex Rossignol 1964) Sarjeant 1970, and Thalassiphora balcanica... |
| Tipo: Text |
Palavras-chave: Spiniferites; Achomosphaera; Hafniasphaera; Rottnestia; Pterocysta. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00471/58304/60844.pdf |
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| Eynaud, Frederique; Malaize, Bruno; Zaragosi, Sebastien; De Vernal, Anne; Scourse, James; Pujol, Claude; Cortijo, Elsa; Grousset, Francis E.; Penaud, Aurelie; Toucanne, Samuel; Turon, Jean-louis; Auffret, Gerard. |
| During the late Quaternary, both external and internal forcings have driven major climatic shifts from glacial to interglacial conditions. Nonlinear climatic steps characterized the transitions leading to these extrema, with intermediate excursions particularly well expressed in the dynamics of the Northern Hemisphere cryosphere. Here we document the impact of these dynamics on the north-eastern North Atlantic Ocean, focussing on the 35-10 ka interval. Sea-surface salinities have been reconstructed quantitatively based on two independent methods from core MD95-2002, recovered from the northern Bay of Biscay adjacent to the axis of the Manche paleoriver outlet and thus in connection with proximal European ice sheets and glaciers. Quantitative... |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00086/19762/20100.pdf |
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