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| Frigola, J.; Canals, M.; Cacho, I.; Moreno, A.; Sierro, F. J.; Flores, J. A.; Berne, Serge; Jouet, Gwenael; Dennielou, Bernard; Herrera, G.; Pasqual, C.; Grimalt, J. O.; Galavazi, M.; Schneider, R.. |
| Borehole PRGL1-4 drilled in the upper slope of the Gulf of Lion provides an exceptional record to investigate the impact of late Pleistocene orbitally-driven glacio-eustatic sea-level oscillations on the sedimentary outbuilding of a river fed continental margin. High-resolution grain-size and geochemical records supported by oxygen isotope chronostratigraphy allow reinterpreting the last 500 ka upper slope seismostratigraphy of the Gulf of Lion. Five main sequences, stacked during the sea-level lowering phases of the last five glacial-interglacial 100-kyr cycles, form the upper stratigraphic outbuilding of the continental margin. The high sensitivity of the grain-size record down the borehole to sea-level oscillations can be explained by the great width of... |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00088/19944/17599.pdf |
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| Rogerson, M.; Cacho, I.; Jimenez-espejo, F.; Reguera, M. I.; Sierro, F. J.; Martinez-ruiz, F.; Frigola, J.; Canals, M.. |
| The eastern Mediterranean sapropels are among the most intensively investigated phenomena in the paleoceanographic record, but relatively little has been written regarding the origin of the equivalent of the sapropels in the western Mediterranean, the organic-rich layers (ORLs). ORLs are recognized as sediment layers containing enhanced total organic carbon that extend throughout the deep basins of the western Mediterranean and are associated with enhanced total barium concentration and a reduced diversity (dysoxic but not anoxic) benthic foraminiferal assemblage. Consequently, it has been suggested that ORLs represent periods of enhanced productivity coupled with reduced deep ventilation, presumably related to increased continental runoff, in close... |
| Tipo: Text |
Palavras-chave: Sapropel; Mediterranean; Sea level; Paleoceanography; Circulation. |
| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00237/34825/33303.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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| Frigola, J.; Moreno, A.; Cacho, I.; Canals, M.; Sierro, F. J.; Flores, J. A.; Grimalt, J. O.; Hodell, D. A.; Curtis, J. H.. |
| The detailed analysis of the International Marine Past Global Changes Study core MD99-2343 recovered from a sediment drift at 2391 m water depth north of the island of Minorca illustrates the effects of climate variability on thermohaline circulation in the western Mediterranean during the last 12 kyr. Geochemical ratios associated with terrigenous input resulted in the identification of four phases representing different climatic and deepwater overturning conditions in the Western Mediterranean Basin during the Holocene. Superimposed on the general trend, eight centennial- to millennial-scale abrupt events appear consistently in both grain size and geochemical records, which supports the occurrence of episodes of deepwater overturning reinforcement in the... |
| Tipo: Text |
Palavras-chave: Holocene climate variability; Thermohaline circulation; Western Mediterranean Sea. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00233/34448/32900.pdf |
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| Berger, A.; Crucifix, M.; Hodell, D. A.; Mangili, C.; Mcmanus, J. F.; Otto-bliesner, B.; Pol, K.; Raynaud, D.; Skinner, L. C.; Tzedakis, P. C.; Wolff, E. W.; Yin, Q. Z.; Abe-ouchi, A.; Barbante, C.; Brovkin, V.; Cacho, I.; Capron, E.; Ferretti, P.; Ganopolski, A.; Grimalt, J. O.; Hoenisch, B.; Kawamura, K.; Landais, A.; Margari, V.; Martrat, B.; Masson-delmotte, V.; Mokeddem, Zohra; Parrenin, F.; Prokopenko, A. A.; Rashid, H.; Schulz, M.; Riveiros, N. Vazquez. |
| Interglacials, including the present (Holocene) period, are warm, low land ice extent (high sea level), end-members of glacial cycles. Based on a sea level definition, we identify eleven interglacials in the last 800,000years, a result that is robust to alternative definitions. Data compilations suggest that despite spatial heterogeneity, Marine Isotope Stages (MIS) 5e (last interglacial) and 11c (similar to 400ka ago) were globally strong (warm), while MIS 13a (similar to 500ka ago) was cool at many locations. A step change in strength of interglacials at 450ka is apparent only in atmospheric CO2 and in Antarctic and deep ocean temperature. The onset of an interglacial (glacial termination) seems to require a reducing precession parameter (increasing... |
| Tipo: Text |
Palavras-chave: Interglacials; Review; Quaternary. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00340/45150/44547.pdf |
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| López-otálvaro, G.-e.; Flores, J. A.; Sierro, F. J.; Cacho, I.; Grimalt, J.-o.; Michel, Elisabeth; Cortijo, E.; Labeyrie, L.. |
| Variations in the assemblages and abundances of calcareous nannoplankton have allowed us to interpret changes in oceanic and atmospheric dynamics in the Guyana Basin, mainly linked to the southeast trades over the last climatic cycle. Records of the paleoproductivity index of coccolithophores (N ratio) allowed us to monitor the nutri-thermocline fluctuations. Additionally, nannofossil accumulation rates vary closely with the N ratio, indicating a strong correlation between these two paleoproductivity proxies. The dominance of upper (small Noelaerhabdaceae, Emiliania huxleyi and Gephyrocapsa oceanica), over lower photic zone dwellers (Florisphaera profunda) during Termination II and interglacial substages 5.1 and 5.3 is related to eutrophic conditions due... |
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| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00240/35111/33608.pdf |
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| Pena, L. D.; Goldstein, S. L.; Hemming, S. R.; Jones, K. M.; Calvo, E.; Pelejero, C.; Cacho, I.. |
| The Southern Ocean is increasingly recognized as a key player in the general ocean thermohaline circulation and the global climate system during glacial interglacial transitions. In particular, the advection of Southern Ocean intermediate waters (SOIW), like Antarctic Intermediate Water and Sub-Antarctic Mode Water, to the Eastern Equatorial Pacific (EEP), through a so-called "oceanic tunnelling" mechanism, is an important means for rapid transfer of climatic signals (such as heat, fresh water, salt, and chemical species) from high-to-low latitudes. However, information on how intermediate water advection rates changed in the past, and particularly during deglaciations, is fragmentary. We present new results for Nd isotopes (epsilon(Nd)) in cleaned... |
| Tipo: Text |
Palavras-chave: Neodymium isotopes; Planktonic foraminifera; Intermediate water masses; Eastern Equatorial Pacific; Equatorial Undercurrent; Southern Ocean. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00264/37543/36928.pdf |
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