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| Yu, J.; Menviel, L.; Jin, Z. D.; Thornalley, D. J. R.; Barker, S.; Marino, G.; Rohling, E. J.; Cai, Y.; Zhang, F.; Wang, X.; Dai, Y.; Chen, P.; Broecker, W. S.. |
| Atmospheric CO2 concentrations declined markedly about 70,000 years ago, when the Earth's climate descended into the last glaciation. Much of the carbon removed from the atmosphere has been suspected to have entered the deep oceans, but evidence for increased carbon storage remains elusive. Here we use the B/Ca ratios of benthic foraminifera from several sites across the Atlantic Ocean to reconstruct changes in the carbonate ion concentration and hence the carbon inventory of the deep Atlantic across this transition. We find that deep Atlantic carbonate ion concentration declined by around 25 mu mol kg(-1) between similar to 80,000 and 65,000 years ago. This drop implies that the deep Atlantic carbon inventory increased by at least 50 Gt around the same... |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53257/83375.pdf |
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| Siddall, M.; Rohling, E. J.; Thompson, W. G.; Waelbroeck, Claire. |
| To develop a better understanding of the abrupt Dansgaard-Oeschger mode of climate change, it is essential that we establish whether the ice sheets are actively involved, as trigger or amplifier, or whether they merely respond in a passive manner. This requires careful assessment of the fundamental issues of magnitude and phasing of global ice volume fluctuations within marine isotope stage 3 (MIS 3), which to date remain enigmatic. We review recent advances in observational studies pertaining to these key issues and discuss the implications for modeling studies. Our aim is to construct a robust stratigraphic framework for the MIS 3 period regarding sea level variability, using the most up-to-date arguments available by combining insights from both... |
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| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00236/34773/33374.pdf |
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| Rogerson, M.; Rohling, E. J.; Bigg, G. R.; Ramirez, J.. |
| The Mediterranean Sea provides a major route for heat and freshwater loss from the North Atlantic and thus is an important cause of the high density of Atlantic waters. In addition to the traditional view that loss of fresh water via the Mediterranean enhances the general salinity of the North Atlantic, and the interior of the eastern North Atlantic in particular, it should be noted that Mediterranean water outflowing at Gibraltar is in fact cooler than compensating inflowing water. The consequence is that the Mediterranean is also a region of heat loss from the Atlantic and contributes to its large-scale cooling. Uniquely, this system can be understood physically via the constraints placed on it by a single hydraulic structure: the Gibraltar exchange.... |
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| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00265/37655/36910.pdf |
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| Grant, K. M.; Grimm, R.; Mikolajewicz, U.; Marino, G.; Ziegler, M.; Rohling, E. J.. |
| The Mediterranean basin is sensitive to global sea-level changes and African monsoon variability on orbital timescales. Both of these processes are thought to be important to the deposition of organic-rich sediment layers or 'sapropels' throughout the eastern Mediterranean, yet their relative influences remain ambiguous. A related issue is that an assumed 3-kyr lag between boreal insolation maxima and sapropel mid-points remains to be tested. Here we present new geochemical and ice-volume-corrected planktonic foraminiferal stable isotope records for sapropels S1 (Holocene), S3, S4, and S5 (Marine Isotope Stage 5) in core LC21 from the southern Aegean Sea. The records have a radiometrically constrained chronology that has already been synchronised with the... |
| Tipo: Text |
Palavras-chave: Eastern Mediterranean; Sapropels; African monsoon; Sea level; Ice sheets; Insolation; Precession; Meltwater pulses. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53245/83374.pdf |
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| Satow, C.; Tomlinson, E. L.; Grant, K. M.; Albert, P. G.; Smith, V. C.; Manning, C. J.; Ottolini, L.; Wulf, S.; Rohling, E. J.; Lowe, J. J.; Blockley, S. P. E.; Menzies, M. A.. |
| Tephra layers preserved in marine sediments can contribute to the reconstruction of volcanic histories and potentially act as stratigraphic isochrons to link together environmental records. Recent developments in the detection of volcanic ash (tephra) at levels where none is macroscopically visible (so-called ‘crypto-tephra’) have greatly enhanced the potential of tephrostratigraphy for synchronising environmental and archaeological records by expanding the areas over which tephras are found. In this paper, crypto-tephra extraction techniques allow the recovery of 8 non-visible tephra layers to add to the 9 visible layers in a marine sediment core (LC21) from the SE Aegean Sea to form the longest, single core record of volcanic activity in the Aegean Sea.... |
| Tipo: Text |
Palavras-chave: Tephra; Trace elements; Santorini; Campanian Ignimbrite; Pantelleria; Kos; Yali; Aegean sea; Mediterranean. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00294/40498/39433.pdf |
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| Waelbroeck, C.; Paul, A.; Kucera, M.; Rosell-mele, A.; Weinelt, M.; Schneider, R.; Mix, A. C.; Abelmann, A.; Armand, L.; Bard, E.; Barker, S.; Barrows, T. T.; Benway, H.; Cacho, I.; Chen, M. T.; Cortijo, E.; Crosta, X.; De Vernal, A.; Dokken, T.; Duprat, J.; Elderfield, H.; Eynaud, F.; Gersonde, R.; Hayes, A.; Henry, M.; Hillaire-marcel, C.; Huang, C. C.; Jansen, E.; Juggins, S.; Kallel, N.; Kiefer, T.; Kienast, M.; Labeyrie, L.; Leclaire, H.; Londeix, L.; Mangin, S.; Matthiessen, J.; Marret, F.; Meland, M.; Morey, A. E.; Mulitza, S.; Pflaumann, U.; Pisias, N. G.; Radi, T.; Rochon, A.; Rohling, E. J.; Sbaffi, L.; Schafer-neth, C.; Solignac, S.; Spero, H.; Tachikawa, K.; Turon, J. -l.. |
| Observation-based reconstructions of sea surface temperature from relatively stable periods in the past, such as the Last Glacial Maximum, represent an important means of constraining climate sensitivity and evaluating model simulations. The first quantitative global reconstruction of sea surface temperatures during the Last Glacial Maximum was developed by the Climate Long-Range Investigation, Mapping and Prediction (CLIMAP) project in the 1970s and 1980s. Since that time, several shortcomings of that earlier effort have become apparent. Here we present an updated synthesis of sea surface temperatures during the Last Glacial Maximum, rigorously defined as the period between 23 and 19 thousand years before present, from the Multiproxy Approach for the... |
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| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00218/32914/31395.pdf |
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| Rogerson, M.; Colmenero-hidalgo, E.; Levine, R. C.; Rohling, E. J.; Voelker, A. H. L.; Bigg, G. R.; Schoenfeld, J.; Cacho, I.; Sierro, F. J.; Lowemark, L.; Reguera, M. I.; De Abreu, L.; Garrick, K.. |
| The Atlantic-Mediterranean exchange of water at Gibraltar represents a significant heat and freshwater sink for the North Atlantic and is a major control on the heat, salt and freshwater budgets of the Mediterranean Sea. Consequently, an understanding of the response of the exchange system to external changes is vital to a full comprehension of the hydrographic responses in both ocean basins. Here, we use a synthesis of empirical (oxygen isotope, planktonic foraminiferal assemblage) and modeling (analytical and general circulation) approaches to investigate the response of the Gibraltar Exchange system to Atlantic freshening during Heinrich Stadials (HSs). HSs display relatively flat W-E surface hydrographic gradients more comparable to the Late Holocene... |
| Tipo: Text |
Palavras-chave: Atlantic; Mediterranean; Gibraltar; Heinrich Event; Last Glacial Maximum; Mediterranean Outflow. |
| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00231/34189/32775.pdf |
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