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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... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00461/57261/59304.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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| 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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| Hodell, D. A.; Lourens, L.; Stow, D. A. V.; Hernández-molina, J.; Alvarez Zarikian, C. A.. |
| Nick Shackleton's research on piston cores from the Iberian margin highlighted the importance of this region for providing high-fidelity records of millennial-scale climate variability, and for correlating climate events from the marine environment to polar ice cores and European terrestrial sequences. During the Integrated Ocean Drilling Program (IODP) Expedition 339, we sought to extend the Iberian margin sediment record by drilling with the D/V JOIDES Resolution. Five holes were cored at Site U1385 using the advanced piston corer (APC) system to a maximum depth of ~155.9 m below sea floor (m b.s.f.). Immediately after the expedition, cores from all holes were analyzed by core scanning X-ray fluorescence (XRF) at 1 cm spatial resolution. Ca/Ti data were... |
| Tipo: Text |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00274/38503/37009.pdf |
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