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Tzedakis, P. C.; Wolff, E. W.; Skinner, L. C.; Brovkin, V.; Hodell, D. A.; Mcmanus, J. F.; Raynaud, D.. |
Differences in the duration of interglacials have long been apparent in palaeoclimate records of the Late and Middle Pleistocene. However, a systematic evaluation of such differences has been hampered by the lack of a metric that can be applied consistently through time and by difficulties in separating the local from the global component in various proxies. This, in turn, means that a theoretical framework with predictive power for interglacial duration has remained elusive. Here we propose that the interval between the terminal oscillation of the bipolar seesaw and three thousand years (kyr) before its first major reactivation provides an estimate that approximates the length of the sea-level high-stand, a measure of interglacial duration. We apply this... |
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Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00266/37694/35838.pdf |
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Tzedakis, P. C.; Drysdale, R. N.; Margari, V.; Skinner, L. C.; Menviel, L.; Rhodes, R. H.; Taschetto, A. S.; Hodell, D. A.; Crowhurst, S. J.; Hellstrom, J. C.; Fallick, A. E.; Grimalt, J. O.; Mcmanus, J. F.; Martrat, B.; Mokeddem, Zohra; Parrenin, F.; Regattieri, E.; Roe, K.; Zanchetta, G.. |
Considerable ambiguity remains over the extent and nature of millennial/centennial-scale climate instability during the Last Interglacial (LIG). Here we analyse marine and terrestrial proxies from a deep-sea sediment sequence on the Portuguese Margin and combine results with an intensively dated Italian speleothem record and climate-model experiments. The strongest expression of climate variability occurred during the transitions into and out of the LIG. Our records also document a series of multi-centennial intra-interglacial arid events in southern Europe, coherent with cold water-mass expansions in the North Atlantic. The spatial and temporal fingerprints of these changes indicate a reorganization of ocean surface circulation, consistent with... |
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Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00461/57261/59304.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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Margari, Vasiliki; Skinner, Luke C.; Hodell, David A.; Martrat, Belen; Toucanne, Samuel; Grimalt, Joan O.; Gibbard, Philip L.; Lunkka, J. P.; Tzedakis, P. C.. |
Past glacials can be thought of as natural experiments in which variations in boundary conditions influenced the character of climate change. However, beyond the last glacial, an integrated view of orbital-and millennial-scale changes and their relation to the record of glaciation has been lacking. Here, we present a detailed record of variations in the land-ocean system from the Portuguese margin during the penultimate glacial and place it within the framework of ice-volume changes, with particular reference to European ice-sheet dynamics. The interaction of orbital-and millennial-scale variability divides the glacial into an early part with warmer and wetter overall conditions and prominent climate oscillations, a transitional mid-part, and a late part... |
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Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00187/29819/28295.pdf |
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Govin, A.; Capron, E.; Tzedakis, P. C.; Verheyden, S.; Ghaleb, B.; Hillaire-marcel, C.; St-onge, G.; Stoner, J. S.; Bassinot, F.; Bazin, L.; Blunier, T.; Combourieu-nebout, N.; El Ouahabi, A.; Genty, D.; Gersonde, R.; Jimenez-amat, P.; Landais, A.; Martrat, B.; Masson-delmotte, V.; Parrenin, F.; Seidenkrantz, M. -s.; Veres, D.; Waelbroeck, C.; Zahn, R.. |
The Last Interglacial (LIG) represents an invaluable case study to investigate the response of components of the Earth system to global warming. However, the scarcity of absolute age constraints in most archives leads to extensive use of various stratigraphic alignments to different reference chronologies. This feature sets limitations to the accuracy of the stratigraphic assignment of the climatic sequence of events across the globe during the LIG. Here, we review the strengths and limitations of the methods that are commonly used to date or develop chronologies in various climatic archives for the time span (similar to 140 -100 ka) encompassing the penultimate deglaciation, the LIG and the glacial inception. Climatic hypotheses underlying record... |
Tipo: Text |
Palavras-chave: Last Interglacial; Penultimate deglaciation; Last glacial inception; Chronology; Corals; Speleothems; Ice cores; Marine sediments; Peat and lake sediments; Climate dynamics. |
Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00496/60802/64786.pdf |
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Birner, B.; Hodell, D. A.; Tzedakis, P. C.; Skinner, L. C.. |
Although millennial-scale climate variability (<10ka) has been well studied during the last glacial cycles, little is known about this important aspect of climate in the early Pleistocene, prior to the Middle Pleistocene Transition. Here we present an early Pleistocene climate record at centennial resolution for two representative glacials (marine isotope stages (MIS) 37-41 from approximately 1235 to 1320ka) during the 41ka world at Integrated Ocean Drilling Program Site U1385 (the Shackleton Site) on the southwest Iberian margin. Millennial-scale climate variability was suppressed during interglacial periods (MIS37, MIS39, and MIS41) and activated during glacial inceptions when benthic O-18 exceeded 3.2. Millennial variability during glacials MIS38 and... |
Tipo: Text |
Palavras-chave: Millennial variability; Interhemispheric linkage; Iberian margin; Early Pleistocene. |
Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53289/54199.pdf |
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Tzedakis, P. C.. |
Marine Isotope Stage (MIS) 11 has been considered a potential analogue for the Holocene and its future evolution. However, a dichotomy has emerged over the precise chronological alignment of the two intervals, with one solution favouring a synchronization of the precession signal and another of the obliquity signal. The two schemes lead to different implications over the natural length of the current interglacial and the underlying causes of the evolution of greenhouse gas concentrations. Here, the close coupling observed between changes in southern European tree populations and atmospheric methane concentrations in previous interglacials is used to evaluate the natural vs. anthropogenic contribution to Holocene methane emissions and assess the two... |
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Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00231/34253/33075.pdf |
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