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| Bachem, Paul E.; Risebrobakken, Bjorg; Mcclymont, Erin L.. |
| The mid-Piacenzian warm period (3.264-3.025 Ma) of the Pliocene epoch has been proposed as a possible reference for future warm climate states. However, there is significant disagreement over the magnitude of high latitude warming between data and models for this period of time, raising questions about the driving mechanisms and responsible feedbacks. We have developed a new set of orbital-resolution alkenone-based sea surface temperature (SST) and ice rafted debris (IRD) records from the Norwegian Sea spanning 3.264-3.14 Ma. The SSTs in the Norwegian Sea were 2-3 degrees C warmer than the Holocene average, likely caused by the radiative effect of higher atmospheric CO2 concentrations. There is notable obliquity-driven SST variability with a range of 4... |
| Tipo: Text |
Palavras-chave: Pliocene; Norwegian Sea; ODP Site 642; Alkenones; SST; Subpolar gyre. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53230/83372.pdf |
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| Wall, Torbjorn. |
| High-resolution magnetic hysteresis measurements were carried out on three sediment cores, one from the North Atlantic and two from the Norwegian Sea. These measurements can be used to reconstruct changes in magnetic grain-size. Physical grain-size has been interpreted as a proxy for bottom current intensity (McCave et al. 1995) and this study shows that the hysteresis measurements can contribute as a proxy for near bottom currents in this region during the Holocene, but only when the magnetic measurements are combined with other proxy records. The magnetic grain-size record of one core from the Norwegian Sea has been compared with sea surface temperature reconstructions produced by Calvo et al. (2002) and Birks & Koç (2002). The dominant magnetic... |
| Tipo: Text |
Palavras-chave: Magnetic grain-size; Magnetic hysteresis loops; Reykjanes Ridge; Vøring plateau; North Atlantic; Norwegian Sea; Deep ocean currents; Holocene. |
| Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00499/61042/64449.pdf |
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| Lazar, Cassandre Sara. |
| A large portion of the greenhouse gas methane on Earth is trapped in marine sediments. However, little methane actually reaches the hydrsphere and the atmosphere, because it is efficiently consumed by anaerobic methane-oxidizing Archaea (ANME). This methane is mainly biogenic in marine sédiments, and is produced by methanogenic Archaea. Methane ascends from deep sources to the seabed, in cold seep sites of continental margins. In order to study microbial community diversity in cold seeps, and to determine geochemical factors that control these microbial communities, we compared four geochemically and geologically distinct sites. In this work, molecular tools (PCR, RT-PCR, DGGE, cloning) as well as genetic markers (16S rRNA, mcrA, dsrB) were employed, to... |
| Tipo: Text |
Palavras-chave: Diversité moléculaire; Archaea; Méthanogène; ANME; McrA; DsrB; DGGE; Volcan de boue; Pockmark; Saumures; Fluides froids; Méthane; Mer de Norvège; Mer Méditerranée; Sédiments.; Molecular diversity; Archaea; Methanogen; ANME; McrA; DsrB; DGGE; Mud volcano; Pockmark; Brines; Cold seep; Methane; Norwegian Sea; Mediterranean Sea; Sediments.. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00031/14250/11534.pdf |
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| Dolven, Jk; Cortese, G; Bjorklund, Kr. |
| Polycystine radiolarians are used to reconstruct summer sea surface temperatures (SSSTs) for the Late Pleistocene-Holocene (600-13,400 C-14 years BP) in the Norwegian Sea. At 13,200 C-14 years BP, the SSST was close to the average Holocene SSST (similar to12degreesC). It then gradually dropped to 7.1degreesC in the Younger Dryas. Near the Younger Dryas-Holocene transition (similar to10,000 C-14 years BP), the SSST increased 5degreesC in about 530 years. Four abrupt cooling events, with temperature drops of up to 2.1degreesC, are recognized during the Holocene: at 9340, 7100 ("8200 calendar years event''), 6400 and 1650 C-14 years BP. Radiolarian SSSTs and the isotopic signal from the GISP2 ice core are strongly coupled, stressing the importance of the... |
| Tipo: Text |
Palavras-chave: Radiolarians; Paleoclimate; Late Pleistocene-Holocene; Norwegian Sea. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33384/31894.pdf |
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