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| El Albani, Abderrazak; Bengtson, Stefan; Canfield, Donald E.; Riboulleau, Armelle; Bard, Claire Rollion; Macchiarelli, Roberto; Pemba, Lauriss Ngombi; Hammarlund, Emma; Meunier, Alain; Mouele, Idalina Moubiya; Benzerara, Karim; Bernard, Sylvain; Boulvais, Philippe; Chaussidon, Marc; Cesari, Christian; Fontaine, Claude; Chi-fru, Ernest; Garcia Ruiz, Juan Manuel; Gauthier-lafaye, Francois; Mazurier, Arnaud; Pierson-wickmann, Anne Catherine; Rouxel, Olivier; Trentesaux, Alain; Vecoli, Marco; Versteegh, Gerard J. M.; White, Lee; Whitehouse, Martin; Bekker, Andrey. |
| The Paleoproterozoic Era witnessed crucial steps in the evolution of Earth's surface environments following the first appreciable rise of free atmospheric oxygen concentrations similar to 2.3 to 2.1 Ga ago, and concomitant shallow ocean oxygenation. While most sedimentary successions deposited during this time interval have experienced thermal overprinting from burial diagenesis and metamorphism, the ca. 2.1 Ga black shales of the Francevillian B Formation (FB2) cropping out in southeastern Gabon have not. The Francevillian Formation contains centimeter-sized structures interpreted as organized and spatially discrete populations of colonial organisms living in an oxygenated marine ecosystem. Here, new material from the FB2 black shales is presented and... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00202/31356/29754.pdf |
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| Gupta, Sanjeev; Collier, Jenny S.; Garcia-moreno, David; Oggioni, Francesca; Trentesaux, Alain; Vanneste, Kris; De Batist, Marc; Camelbeeck, Thierry; Potter, Graeme; Van Vliet-lanoe, Brigitte; Arthur, John C. R.. |
| Late Quaternary separation of Britain from mainland Europe is considered to be a consequence of spillover of a large proglacial lake in the Southern North Sea basin. Lake spillover is inferred to have caused breaching of a rock ridge at the Dover Strait, although this hypothesis remains untested. Here we show that opening of the Strait involved at least two major episodes of erosion. Sub-bottom records reveal a remarkable set of sediment-infilled depressions that are deeply incised into bedrock that we interpret as giant plunge pools. These support a model of initial erosion of the Dover Strait by lake overspill, plunge pool erosion by waterfalls and subsequent dam breaching. Cross-cutting of these landforms by a prominent bedrock-eroded valley that is... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00455/56635/58373.pdf |
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| Liu, Zhenxia; Berne, Serge; Saito, Yoshiki; Yu, Hua; Trentesaux, Alain; Uehara, Katsuto; Yin, Ping; Liu, J. Paul; Li, Chaoxing; Hu, Guanghai; Wang, Xiangqin. |
| On the basis of bathymetric and seismic data and data from piston cores collected by the Chinese-French marine geology and geophysics investigation of 1996, we discuss the internal architecture and mobility of tidal sand ridges in the East China Sea (ECS). We characterized the sand ridges on the middle to outer shelf of the ECS as tide-dominated sand ridges with southwest dipping beds, indicating that the regional net sediment transport is toward the southwest. As the sand ridges gradually migrate toward the southwest, new sand ridges are continually replacing old ones, and several generations of sand ridges have developed in the study area. High-resolution seismic data, acoustic Doppler current profiler data, and two C-14-dated piston cores, DGKS9614... |
| Tipo: Text |
Palavras-chave: Transgression; Ridge evolution; East China Sea; Mobility; Internal architecture; Tidal sand ridge. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3309.pdf |
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| Liu, Zhifei; Colin, Christophe; Huang, Wei; Le, Khanh Phon; Tong, Shengqi; Chen, Zhong; Trentesaux, Alain. |
| Results of clay mineralogy, major element geochemistry, and Sr and Nd isotopes in 93 argillaceous samples collected from drainage basins of the Pearl, Red, and Mekong rivers reveal different degrees of chemical weathering in Southeast Asia despite similar climate conditions across these regions. The kaolinite/illite ratio, illite chemistry index, and illite crystallinity can be used as indicators of chemical weathering intensity. These mineralogical proxies combined with the K(2)O/(Na(2)O + CaO) molar ratio, chemical index of alteration (CIA), and weathering trends observed from major element results indicate intensive silicate weathering in the Pearl River basin, moderate to intensive in the Mekong River basin, and moderate in the Red River basin.... |
| Tipo: Text |
Palavras-chave: Clay minerals; Major elements; Chemical weathering; Pearl River; Red River; Mekong River. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00235/34613/32949.pdf |
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| Le Bot, Sophie; Trentesaux, Alain; Garlan, Thierry; Berne, Serge; Chamley, Hervé. |
| The present paper deals with dune dynamics in a zone of the Strait of Dover located in the sea lane running into the North Sea. The dunes, widespread in this 35-m depth area, are mobile sedimentary structures (up to 40 m.yr(-1)) that culminate at a maximum of 22 m depth and endanger navigation as well as submarine man-made structures (cables, pipelines). Single- and multibeam bathymetric data, coupled with seismic data, allow us to follow dune displacements over different time scales. A net bedload parting zone has been displayed and divides the area into two parts, SE and NW. However, according to the considered time-scale, dune movements present Variations in intensity and direction. Over a long-term period (decades), sedimentary dynamics fit the... |
| Tipo: Text |
Palavras-chave: Tempêtes; Dunes tidales; Dynamique sédimentaire; Détroit du Pas de Calais; Storms; Tidal dunes; Sedimentary dynamics; Strait of Dover. |
| Ano: 2000 |
URL: https://archimer.ifremer.fr/doc/2000/publication-519.pdf |
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