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| Registros recuperados: 11 | |
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| De Vernal, A; Hillaire-marcel, C; Peltier, Wr; Weaver, Aj. |
| During the Last Glacial Maximum, the northwestern North Atlantic constituted a major conduit for Labrador and Greenland ice sheet meltwaters. Vertical density gradients in its upper water masses have been reconstructed by combining information from transfer functions based on dinocysts and from oxygen isotope measurements (delta(18)O) in planktonic foraminifera. Transfer functions yield temperature and salinity and thus potential density (sigma(theta)) for the warmest (August) and coldest (February) months in the photic zone. The delta(18)O values in different size fractions of epipelagic (Globigerina bulloides) and mesopelagic (Neogloboquadrina pachyderma left-coiled (Np1)) foraminifera allow us to assess sigma(theta) gradients through the pycnocline... |
| Tipo: Text |
Palavras-chave: Last Glacial Maximum; LGM; North Atlantic; Salinity; Density; Pycnocline. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33405/31861.pdf |
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| Eynaud, Frederique; De Abreu, Lucia; Voelker, Antje; Schoenfeld, Joachim; Salgueiro, Emilia; Turon, Jean-louis; Penaud, Aurelie; Toucanne, Samuel; Naughton, Filipa; Goni, Maria Fernanda Sanchez; Malaize, Bruno; Cacho, Isabel. |
| This paper documents the migration of the Polar Front (PF) over the Iberian margin during some of the cold climatic extremes of the last 45 ka. It is based on a compilation of robust and coherent paleohydrological proxies obtained from eleven cores distributed between 36 and 42 degrees N. Planktonic delta O-18 (Globigerina bulloides), ice-rafted detritus concentrations, and the relative abundance of the polar foraminifera Neogloboquadrina pachyderma sinistral were used to track the PF position. These three data sets, compared from core to core, show a consistent evolution of the sea surface paleohydrology along the Iberian margin over the last 45 ka. We focused on five time slices representative of cold periods under distinct paleoenvironmental forcings:... |
| Tipo: Text |
Palavras-chave: Polar Front; LGM; Heinrich events. |
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00218/32909/31415.pdf |
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| Samartin, Stephanie; Heiri, Oliver; Kaltenrieder, Petra; Kühl, Norbert; Tinner, Willy. |
| Vegetation and climate during the last ice age and the Last Glacial Maximum (LGM, similar to 23,000-19,000 cal BP) were considerably different than during the current interglacial (Holocene). Cold climatic conditions and growing ice-sheets during the last glaciation radically reduced forest extent in Europe to a restricted number of so-called "refugia", mostly located in the southern part of the continent. On the basis of paleobotanical analyses the Euganian Hills (Colli Euganei) in northeastern Italy have previously been proposed as one of the northernmost refugia of temperate trees (e.g. deciduous Quercus, Tilia, Ulmus, Fraxinus excelsior, Acer, Abies alba, Fagus sylvatica, Carpinus and Castanea) in Europe. In this study we provide the first... |
| Tipo: Text |
Palavras-chave: Chironomids; Refugia; Vegetation; Northern Italy; Mediterranean; Climate; Last Glacial; LGM; Heinrich events; Paleoecology; Paleoclimatology. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53234/54773.pdf |
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| Toucanne, Samuel; Zaragosi, S; Bourillet, Jean-francois; Naughton, F; Cremer, M; Eynaud, F; Dennielou, Bernard. |
| High-resolution sedimentological and micropaleontological studies of several deep-sea cores retrieved from the levees of the Celtic and Armorican turbidite systems (Bay of Biscay - North Atlantic Ocean) allow the detection of the major oscillations of the British-Irish Ice Sheet (BIIS) and 'Fleuve Manche' palaeoriver discharges over the last 30,000 years, which were mainly triggered by climate changes. Between 30 and 20 cal ka, the turbiditic activity on the Celtic-Annorican margin was weak, contrasting with previous stratigraphic models which predicted a substantial increase of sediment supply during low sea-level stands. This low turbidite deposit frequency was most likely the result of a weak activity of the 'Fleuve Manche' palaeoriver and/or of a... |
| Tipo: Text |
Palavras-chave: Turbidites; Heinrich events; LGM; Last deglaciation; Palaeoriver; Fleuve Manche; British irish ice sheet; Bay of Biscay. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-3729.pdf |
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| Kelley, Samuel E.; Kaplan, Michael R.; Schaefer, Joerg M.; Andersen, Bjorn G.; Barrell, David J. A.; Putnam, Aaron E.; Denton, George H.; Schwartz, Roseanne; Finkel, Robert C.; Doughty, Alice M.. |
| Millennial-scale temperature variations in Antarctica during the period 80,000 to 18,000 years ago are known to anti-correlate broadly with winter-centric cold-warm episodes revealed in Greenland ice cores. However, the extent to which climate fluctuations in the Southern Hemisphere beat in time with Antarctica, rather than with the Northern Hemisphere, has proved a controversial question. In this study we determine the ages of a prominent sequence of glacial moraines in New Zealand and use the results to assess the phasing of millennial climate change. Forty-four Be-10 cosmogenic surface-exposure ages of boulders deposited by the Pukaki glacier in the Southern Alps document four moraine-building events from Marine Isotope Stage 3 (MIS 3) through to the... |
| Tipo: Text |
Palavras-chave: Be-10 surface-exposure dating; LGM; MIS 3; Southern Hemisphere; Westerly wind field; New Zealand. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00289/40068/39163.pdf |
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| Reeves, Jessica M.; Bostock, Helen C.; Ayliffe, Linda K.; Barrows, Timothy T.; De Deckker, Patrick; Devriendt, Laurent S.; Dunbar, Gavin B.; Drysdale, Russell N.; Fitzsimmons, Kathryn E.; Gagan, Michael K.; Griffiths, Michael L.; Haberle, Simon G.; Jansen, John D.; Krause, Claire; Lewis, Stephen; Mcgregor, Helen V.; Mooney, Scott D.; Moss, Patrick; Nanson, Gerald C.; Purcell, Anthony; Van Der Kaars, Sander. |
| The tropics are the major source of heat and moisture for the Australasian region. Determining the tropics' response over time to changes in climate forcing mechanisms, such as summer insolation, and the effects of relative sea level on exposed continental shelves during the Last Glacial period, is an ongoing process of re-evaluation. We present a synthesis of climate proxy data from tropical Australasia spanning the last 30,000 years that incorporates deep sea core, coral, speleothem, pollen, charcoal and terrestrial sedimentary records. Today, seasonal variability is governed largely by the annual migration of the inter-tropical convergence zone (ITCZ), influencing this region most strongly during the austral summer. However, the position of the ITCZ has... |
| Tipo: Text |
Palavras-chave: ITCZ; LGM; INTIMATE; Australasia; Indo-Pacific Warm Pool; Tropics; Australian monsoon. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00264/37502/36909.pdf |
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| Ujiie, Yurika; Asahi, Hirofumi; Sagawa, Takuya; Bassinot, Franck. |
| The North Pacific Subtropical Gyre (NPSG) has two important functions, i.e., one in ocean heat transfer and another as a driving force for circulation of the surface and intermediate waters on the basin scale. In the present study, we describe records of the vertical thermal structures and distributions of water masses in the upper ocean of the subtropical northwest (NW) Pacific for the past 190 kyr, using two sediment cores collected from the Kuroshio Current area in the East China Sea and the NPSG area. During the two glacial periods, the Kuroshio Current was weakened owing to changes in ocean-atmosphere circulation and eustasy. The differences in the Mg/Ca-derived temperatures between surface and thermocline waters show the changes of depth and... |
| Tipo: Text |
Palavras-chave: North Pacific Subtropical Gyre; LGM; MIS 6; Paleotemperature; Water-column structure. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00358/46911/46812.pdf |
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| Frings, Patrick J.; Clymans, Wim; Fontorbe, Guillaume; De La Rocha, Christina L.; Conley, Daniel J.. |
| The silicon isotope composition of biogenic silica (delta Si-30(BSi)) in the ocean is a function of the delta Si-30 of the available dissolved Si (DSi; H2SiO4), the degree of utilisation of the available DSi, and, for some organisms, the concentration of DSi. This makes delta Si-30(BSi) in sediment archives a promising proxy for past DSi concentrations and utilisation. At steady-state, mean delta Si-30(BSi) must equal a weighted average of the inputs, the majority of which are of continental origin. Variation in the functioning of the continental Si cycle on timescales similar to the residence time of DSi in the ocean (similar to 10 ka) may therefore contribute to downcore variability in delta Si-30(BSi) on millennial or longer time-scales. The direction... |
| Tipo: Text |
Palavras-chave: Global silicon cycle; Biogenic silica; Silicon isotopes; LGM; Palaeoceanography; Biogeochemical cycling. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53252/54714.pdf |
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| Banuls-cardona, S.; Lopez-garcia, J. M.; Blain, H. -a.; Lozano-fernandez, I.; Cuenca-bescos, G.. |
| This paper presents a palaeoenvironmental and palaeoclimatic approach to the end of the Last Glacial Maximum (LGM) in the Iberian Peninsula on the basis of the small-mammal assemblages (insectivores, bats and rodents). The LGM is an important period in our climate history defined by the maximum extension of ice sheets between ca. 22 and 19 ka BP. In the Mediterranean region the LGM is characterized by humid conditions, which allow for the development of arboreal vegetation. The small-mammal remains described in this study were recovered from four different sites within the Iberian Peninsula: El Miron cave (Ramales de la Victoria, Cantabria), Valdavara-1 (Becerrea, Lugo), El Portalon (Sierra de Atapuerca, Burgos), and Sala de las Chimeneas (Maltravieso,... |
| Tipo: Text |
Palavras-chave: Microvertebrate; Palaeoenvironment; Palaeoclimate; LGM; Late Pleistocene. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00291/40239/38657.pdf |
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| Kemp, Justine; Pietsch, Timothy; Gontz, Allen; Olley, Jon. |
| Climatic forcing of fluvial systems has been a pre-occupation of geomorphological studies in Australia since the 1940s. In the Riverine Plain, southeastern Australia, the stable tectonic setting and absence of glaciation have combined to produce sediment loads that are amongst the lowest in the world. Surficial sediments and landforms exceed 140,000 yr in age, and geomorphological change recorded in the fluvial, fluvio-lacustrine and aeolian features have provided a well-studied record of Quaternary environmental change over the last glacial cycle. The region includes the Willandra Lakes, whose distinctive lunette lakes preserve a history of water-level variations and ecological change that is the cornerstone of Australian Quaternary chronostratigraphy.... |
| Tipo: Text |
Palavras-chave: Lake Mungo; Willandra Lakes; Lachlan River; Palaeohydrology; Electromagnetic survey; Palaeochannels; Quaternary; LGM. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00496/60793/64936.pdf |
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| Registros recuperados: 11 | |
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