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| Registros recuperados: 48 | |
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| Stuut, Jan‐berend W.; De Deckker, Patrick; Saavedra‐pellitero, Mariem; Bassinot, Franck; Drury, Anna‐joy; Walczak, Maureen H.; Nagashima, Kana; Murayama, Masafumi. |
| New proxy records from deep‐sea sediment cores from the northwestern continental margin of Western Australian reveal a 5.3 million‐year (Ma) history of aridity and tropical‐monsoon activity in northwestern Australia. Following the warm and dry early Pliocene (~5.3 Ma), the northwestern Australian continent experienced a gradual increase in humidity peaking at about 3.8 Ma with higher than present‐day rainfall. Between 3.8 and about 2.8 Ma, climate became progressively more arid with more rainfall variability. Coinciding with the onset of the northern hemisphere glaciations and the intensification of the northern hemisphere monsoon, aridity continued to increase overall from 2.8 Ma until today, with greater variance in precipitation and an increased... |
| Tipo: Text |
Palavras-chave: Paleoclimate; Monsoon; Australia; Runoff; Pliocene; Quaternary. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00502/61384/65035.pdf |
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| Chen, Chih-wei; Wei, Kuo-yen; Mii, Horng-sheng; Yang, Tien-nan. |
| A detailed oxygen isotope time-scale based on planktonic foraminifera Globigerinoides sacculifer at site MD012380 in the Banda Sea was established for the past 820 kyrs by correlating the record to the astronomically tuned benthic oxygen isotope chronology of MD972143. Ages for marine isotope stratigraphic (MIS) events from 2.0 back to 21.1 were designated for this western tropical Pacific record. Spectral analysis of the 6180 time-series reveals distinct periodicities of 100, 41, and 23 kyrs, indicating strong orbital forcing, yet the power of each band varies through time. The time-series of three other paleo-proxies, namely, coarse fraction (CF), lightness of sediments and delta C-13 of Globigerinoides saccidifer, were subjected to cross-spectral... |
| Tipo: Text |
Palavras-chave: Age model; Oxygen isotope stratigraphy; Quaternary; Banda Sea. |
| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00237/34814/33678.pdf |
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| Van Nieuwenhove, Nicolas; Head, Martin J.; Limoges, Audrey; Pospelova, Vera; Mertens, Kenneth; Matthiessen, Jens; De Schepper, Stijn; De Vernal, Anne; Eynaud, Frédérique; Londeix, Laurent; Marret, Fabienne; Penaud, Aurélie; Radi, Taoufik; Rochon, André. |
| Organic-walled resting cysts of planktonic dinoflagellates occur commonly in modern marine sediment where they represent, with rare exceptions, the only geologically preservable part of the life cycle. Although many species do not produce fossilizable resting cysts, upper Quaternary sediments contain a diverse cyst record that is used frequently for paleoenvironmental reconstruction and stratigraphic analysis. Reconstructions of past sea-surface conditions rely on an understanding of the distributions of dinoflagellate cysts in modern sediments linked to their respective environmental parameters, underpinned by sound taxonomy and standardized nomenclature. Stratigraphic studies additionally require knowledge of morphological details to distinguish extant... |
| Tipo: Text |
Palavras-chave: Dinoflagellate cysts; Marine; Quaternary; Gymnodiniales; Gonyaulacales; Peridiniales. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00606/71817/70324.pdf |
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| Molliex, S.; Jouet, Gwenael; Freslon, Nicolas; Bourles, D. L.; Authemayou, C.; Moreau, Julien; Rabineau, Marina. |
| The Mediterranean domain is characterized by a specific climate resulting from the close interplay between atmospheric and marine processes and strongly differentiated regional topographies. Corsica Island, a mountainous area located in the western part of the Mediterranean Sea is particularly suitable to quantify regional denudation rates in the framework of a source-to-sink approach. Indeed, fluvial sedimentation in East-Corsica margin is almost exclusively limited to its alluvial plain and offshore domain and its basement is mainly constituted of quartz-rich crystalline rocks allowing cosmogenic nuclide Be-10 measurements. In this paper, Holocene denudation rates of catchments from the eastern part of the island of Corsica are quantified relying on in... |
| Tipo: Text |
Palavras-chave: Be-10-derived denudation rates; Schmidt Hammer; Quaternary; Quantitative geomorphology; Weathering. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00380/49082/49655.pdf |
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| Cabioch, G; Correge, T; Turpin, L; Castellaro, C; Recy, J. |
| In New Caledonia, core data indicate that the fringing reefs grew during the last interglacial and the Holocene, while the barrier reefs developed during several high sea level stands of the Quaternary. These growth periods are archived in a 128-m-long core from Ilot Amedee, offshore of Noumea. Directly upon the peridotitic substrate (reached at 126.50 m), a basal unit comprising abundant rhodoliths, molluscs and rare corals is characteristic of the pioneer stage of barrier reef development. Above it, a severely calcitized unit contains corals, molluscs and abundant micritic levels. Then, a sequence punctuated by several minor discontinuities and by a downward increase in diagenetic alteration is found. At 47 m core depth, a unit, which is thought to be... |
| Tipo: Text |
Palavras-chave: Croissance récifale; Néotectonique; Nouvelle-Calédonie; Quaternaire; Reef growth; Neotectonics; New Caledonia; Quaternary. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00325/43582/44021.pdf |
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| Nova,Patricia Villa; Avilla,Leonardo S.; Oliveira,Édison V.. |
| The present study acknowledges the diversity of fossil marsupials from the Gruta dos Moura cave, as well as environmental and climatic aspects during the Quaternary. The results show that this is the largest diversity of Pleistocene marsupials recorded in a single cave: Didelphis albiventris, D. aurita, Gracilinanus agilis, G. microtarsus, Marmosa murina, Monodelphis brevicaudata, M. domesticaand Sairadelphys tocantinensis. Furthermore, the described specimens are also part of the only fossil assemblage unequivocally referable to the late Pleistocene. Paleontological studies suggest an intimate association with dry and open environments with high abundance of water sources. Since most of the identified taxa are characteristic of open forests and gallery... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mammals; Didelphidae; Marsupials; Northern Brazil; Quaternary; Late Pleistocene. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652015000100193 |
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| GAUDIOSO,PABLO J.; GASPARINI,GERMÁN M.; HERBST,RAFAEL; BARQUEZ,RUBÉN M.. |
| ABSTRACT The first record of the Neolicaphrium recens Frenguelli, 1921 (Mammalia, Litopterna) from Pleistocene deposits of the Río Dulce, Rio Hondo Department, Santiago del Estero Province, Argentina, is reported. The morphology and morphometry observed in the specimen MPAT073 is coincident with the diagnostic characteristics of that species. This finding represents the northernmost and westernmost record of the species, and thus extends its geographical distribution. Geological data suggest that the material comes from a still unnamed Pleistocene stratigraphic unit. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Proteroteridae; Termas de Río Hondo; Northwestern Argentina; Río Dulce; Quaternary. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0031-10492017000300023 |
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| Cheshire, Heather; Thurow, Juergen. |
| Guaymas Basin, Gulf of California, is a restricted basin located under the present-day wet/dry subtropical divide (similar to 27 degrees N) and is ideally circumstanced for detecting variations in the North Pacific Subtropical High (NPSH)/Trade Wind system. Controlled by climate cell boundary displacement, NPSH midwinter location was the primary influence on timing and intensity of upwelling seasons in Guaymas Basin. Analysis of high-resolution X-ray fluoresence data and sediment fabric log from 75% laminated Core MD02-2517/2515, western Guaymas Basin, reveals systematic changes in NPSH behavior over the last similar to 55 kyr BP. Southward displacement of the wet/dry subtropical divide controlled upwelling-related diatom productivity, while sea level and... |
| Tipo: Text |
Palavras-chave: Quaternary; Paleoceanography; X-ray fluorescence; Laminated sediment. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00264/37527/35762.pdf |
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| Berben, Sarah M.p.; Dokken, Trond M.; Abbott, Peter M.; Cook, Eliza; Sadatzki, Henrik; Simon, Margit H; Jansen, Eystein. |
| Understanding the dynamics that drove past abrupt climate changes, such as the Dansgaard-Oeschger (DO) events, depends on combined proxy evidence from disparate archives. To identify leads, lags and synchronicity between different climate system components, independent and robust chronologies are required. Cryptotephrochronology is a key geochronological tool as cryptotephra horizons can act as isochrons linking disparate and/or distant records. Here, we investigated marine sediment core MD99-2284 from the Norwegian Sea to look for previously identified Greenland ice core cryptotephra horizons and define time-parallel markers between the archives. We explored potential secondary transport and depositional mechanisms that could hamper the isochronous... |
| Tipo: Text |
Palavras-chave: Quaternary; Paleoclimatology; Paleoceanography; North Atlantic; Sedimentology; Marine cores; Ice cores; Cryptotephrochronology; DO-Events; Synchronization. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00622/73391/72606.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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| 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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| Sá,Natália de Paula; Absy,Maria Lúcia; Soares,Emílio Alberto Amaral. |
| ABSTRACT The core PD-67 of 160 cm depth was collected from the delta of Lake Cabaliana situated on the Solimões River. Seventeen samples were removed for palynological and sedimentological analysis and three for radiocarbon analysis. Two dry periods, both in the Late Holocene, were observed (2800-2550 cal yr BP, 1450-550 cal yr BP) separated by a wetter phase (2550-1450 cal yr BP). In 2800-2550 cal yr BP, varzea forests of Alchornea, Symmeria, Cecropia, Alternanthera and Asteraceae were predominant. Beginning in 2,550-1450 cal yr BP, the varzea was characterized by pioneer elements, such as Cassia, Laetia, Mabea, Symmeria and Cecropia, and by the expansion of Poaceae, Cyperaceae, Sagittaria, Montrichardia and Asteraceae. In 1450-550 cal yr BP the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Amazon; Pollen; Quaternary; Rainfall; Terra firme forest. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062016000300473 |
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| FERREIRA,THAIS M.F.; OLIVARES,ADRIANA ITATI; KERBER,LEONARDO; DUTRA,RODRIGO P.; AVILLA,LEONARDO S.. |
| ABSTRACT Echimyidae (spiny rats, tree rats and the coypu) is the most diverse family of extant South American hystricognath rodents (caviomorphs). Today, they live in tropical forests (Amazonian, coastal and Andean forests), occasionally in more open xeric habitats in the Cerrado and Caatinga of northern South America, and open areas across the southern portion of the continent (Myocastor). The Quaternary fossil record of this family remains poorly studied. Here, we describe the fossil echimyids found in karst deposits from southern Tocantins, northern Brazil. The analyzed specimens are assigned to Thrichomys sp., Makalata cf. didelphoides and Proechimys sp. This is the first time that a fossil of Makalata is reported. The Pleistocene record of echimyids... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Caviomorphs; Echimyidae; Fossil record; Quaternary; South America. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652016000300829 |
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| Registros recuperados: 48 | |
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