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| Registros recuperados: 105 | |
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| Hussein,Kamal M.. |
| The goal of this research was to reconstruct the vegetational and climatic changes that took place during the late Pleisocene and Holocene in southwestern Syria. This reconstruction was based on palynological data obtained from the analysis of 27 sediments and surface samples (with a total thickness of 4.55 m) collected from Al-Hijaneh Lake basin (late Pleistocene) and from Al-Aouaj River valley (Holocene). Three pollen zones were established. The oldest one (zone A) corresponds to the late Pleistocene lacustrine deposits of Lake Al-Hijaneh. Zones B and C were defined in the Holocene fluvial- lacustrine deposits of the Al-Aouaj River valley. These three pollen assemblage zones are correlated to synchronic and similar C14 dated pollen zones from Syria,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Flora; Holocene; Late Pleistocene; Paleoclimates; Palynology; Syria. |
| Ano: 2006 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0011-67932006000200003 |
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| Fanget, Anne-sophie; Berne, Serge; Jouet, Gwenael; Bassetti, Maria-angela; Dennielou, Bernard; Maillet, Gregoire M.; Tondut, Mathieu. |
| The modern Rhone delta in the Gulf of Lions (NW Mediterranean) is a typical wave-dominated delta that developed after the stabilization of relative sea level following the last deglacial sea-level rise. Similar to most other deltas worldwide, it displays several stacked parasequences and lobes that reflect the complex interaction between accommodation, sediment supply and autogenic processes on the architecture of a wave-dominated delta. The interpretation of a large set of newly acquired very high-resolution seismic and sedimentological data, well constrained by 14C dates, provides a refined three-dimensional image of the detailed architecture (seismic bounding surfaces, sedimentary facies) of the Rhone subaqueous delta, and allows us to propose a... |
| Tipo: Text |
Palavras-chave: Delta; Holocene; Maximum Flooding Surface; Sea level; Tempestites; Western Mediterranean. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00179/29017/27445.pdf |
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| Babonneau, Nathalie; Cattaneo, Antonio; Ratzov, Gueorgui; Deverchere, Jacques; Yelles-chaouche, Abdelkarim; Lateb, Tassadit; Bachir, Roza Si. |
| Northern Algeria is threatened by moderate to large magnitude earthquakes resulting from the slow convergence between the African and European plates. Main active faults are located offshore along the Algerian coast, as exemplified by the 2003 Mw 6.9 Boumerdès earthquake. This event triggered numerous and widespread turbidity currents over ∼ 150 km along strike in the Algerian basin (reaching 2800 m of water depth) and demonstrates the multi-source and multi-path characteristics of earthquake-triggered turbidity flows along this margin segment. We rely on the sedimentological analysis of five cores located at the toe of the Algiers margin, close to the 2003 cable break sites, to explore the potential for Holocene turbidite paleoseismology. Radiocarbon... |
| Tipo: Text |
Palavras-chave: Algerian margin; Marine paleoseismology; Turbidite; Holocene. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00356/46701/46563.pdf |
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| Vann, Cd; Cronin, Tm; Dwyer, Gs. |
| Population ecology and shell chemistry were studied in the phytal ostracode Loxoconcha matagordensis (Swain 1955) collected from Zostera marina seagrass beds in the Chesapeake Bay to provide seasonal constraints on shell secretion time for paleothermometry. Population density and age structure were defined by two main breeding cycles that occurred between 01 to 15 June and 02 to 16 August 2001. The time interval between breeding cycles was similar to2 months and total juvenile standing crop increased almost three-fold between the first and second breeding cycles. Dark brown over-wintered adults comprised the majority of the population between March and April 2001, while newly secreted translucent adults were predominant between June and September. Seasonal... |
| Tipo: Text |
Palavras-chave: Ostracoda; Paleoclimatology; Ecology; Minor elements; Holocene; Seagrass. |
| Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00229/33995/32356.pdf |
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| Dennielou, Bernard; Jallet, Laurent; Sultan, Nabil; Jouet, Gwenael; Giresse, Pierre; Voisset, Michel; Berne, Serge. |
| Emplacement of post-glacial turbidites is commonly controlled by rapid changes in sea level or by seismicity. On the continental rise of the Gulf of Lions (Western Mediterranean), an aseismic area, we identified turbiditic beds deposited during the rising stage and highstand of sea level. Swath bathymetry, sediment cores, in situ Cone Penetrating Tests (CPTU), heavy mineral associations and radiocarbon dating determined the source, composition, distribution and age of the turbiditic beds. Turbidites are composed of homogeneous to positively graded silts to medium sand with quartz (up to 90%), shell debris and shelfal benthic faunas. Their distribution on the sea floor is very patchy and controlled by abundant inherited erosional bedforms. Their source is... |
| Tipo: Text |
Palavras-chave: Holocene; Late Pleistocene; Sea level; Turbidites; Sand; Outer shelf; Canyons. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6316.pdf |
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| Toomey, Michael; Cantwell, Meagan; Colman, Steven; Cronin, Thomas; Donnelly, Jeffrey; Giosan, Liviu; Heil, Clifford; Korty, Robert; Marot, Marci; Willard, Debra. |
| The hazards posed by infrequent major floods to communities along the Susquehanna River and the ecological health of Chesapeake Bay remain largely unconstrained due to the short length of streamgage records. Here we develop a history of high‐flow events on the Susquehanna River during the late Holocene from flood deposits contained in MD99‐2209, a sediment core recovered in 26 m of water from Chesapeake Bay near Annapolis, Maryland, USA. We identify coarse‐grained deposits left by Hurricane Agnes (1972) and the Great Flood of 1936, as well as during three intervals that predate instrumental flood records (~1800‐1500, 1300‐1100 and 400‐0 CE). Comparison to sedimentary proxy data (pollen and ostracode Mg/Ca ratios) from the same core site indicate that... |
| Tipo: Text |
Palavras-chave: Hurricane; Flood; Holocene; East coast; River; Chesapeake. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00483/59447/62291.pdf |
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| Clave, B; Masse, L; Carbonel, P; Tastet, Jp. |
| The La Perroche marsh is a small Holocene marsh on the south-western coast of the Oleron island (Bay of Biscay, France) presently occupied by a freshwater swamp and separated from the ocean by a continuous sand dune ridge. The study of its infill shows first basal conglomeratic deposits with calcareous pebbles on a Cenomanian rough substrate. The Holocene infill since 6000 years BP begins with a very fast sedimentation of sands. Then, the sedimentation becomes finer, with lagoonal to freshwater influences recorded by ostracods. The distribution of these deposits inside the marsh is asymmetric, with a thick sandy-gravely layer in the eastern part and a succession of sands, clays and organic layers in the western part. Communication with the sea is episodic,... |
| Tipo: Text |
Palavras-chave: Changements côtiers; Marais maritime; Holocène; Ostracodes; Sédiments; Coastal changes; Coastal salt marsh; Holocene; Ostracods; Sediments. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00322/43349/42877.pdf |
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| Bugelmayer-blaschek, Marianne; Roche, Didier M.; Renssen, Hans; Andrews, John T.. |
| The climate of the Holocene, the current interglacial covering the past 11,700 years, has been relatively stable compared to previous periods. Nevertheless, repeating occurrence of rapid natural climate changes that challenged human society are seen in proxy reconstructions. Ocean sediment cores for example display prominent peaks of enhanced ice rafted debris (IRD) during the Holocene with a multidecadal to millennial scale periodicity. Different mechanisms were proposed that caused these enhanced IRD events, for example variations in the incoming total solar irradiance (TSI), volcanic eruptions and the combination of internal climate variability and external forcings. We investigate the probable mechanisms causing the occurrence of IRD-events over the... |
| Tipo: Text |
Palavras-chave: Greenland ice sheet; Holocene; Bond events; Icebergs; Climate modeling. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53253/54711.pdf |
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| Arnaud, Fabien; Revillon, Sidonie; Debret, Maxime; Revel, Marie; Chapron, Emmanuel; Jacob, Jeremy; Giguet-covex, Charline; Poulenard, Jerome; Magny, Michel. |
| Two well-dated ca Holocene-long sedimentary sequences from deepest parts of Lake Bourget provide new insights onto the evolution of erosion patterns at a regional scale in NW European Alps. The combination of high resolution geochemistry - XRF core scanning, calibrated by 150 punctual measurements - and isotope geochemistry (epsilon Nd) of the terrigenous fraction permitted the reconstruction not only of the intensity, but also the type (physical erosion vs. chemical weathering) and the location (Prealpine massifs vs. High Crystalline massifs) of dominant erosion processes. Those data point the persistency of weak erosion fluxes from 9600 to 5500 cal. BP due both to a dry climate and the growing sheltering effect of soils that rapidly progressed between... |
| Tipo: Text |
Palavras-chave: Holocene; Alps; Erosion; Soil dynamics; Paleohydrology. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00106/21723/20064.pdf |
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| Cronin, Tm; Dwyer, Gs; Kamiya, T; Schwede, S; Willard, Da. |
| We present paleoclimate evidence for rapid (< 100 years) shifts of similar to 2-4 degreesC in Chesapeake Bay (CB) temperature similar to 2100, 1600, 950, 650, 400 and 150 years before present (years BP) reconstructed from magnesium/calcium (Mg/Ca) paleothermometry. These include large temperature excursions during the Little Ice Age (similar to 1400-1900 AD) and the Medieval Warm Period (similar to 800-1300 AD) possibly related to changes in the strength of North Atlantic thermohaline circulation (THC). Evidence is presented for a long period of sustained regional and North Atlantic-wide warmth with low-amplitude temperature variability between similar to450. and 1000 AD. In addition to centennial-scale temperature shifts, the existence of numerous... |
| Tipo: Text |
Palavras-chave: Paleoclimatology; Holocene; Medieval Warm Period; Little Ice Age; 20th century climate; North Atlantic Oscillation. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00225/33648/32092.pdf |
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| Risebrobakken, B; Jansen, E; Andersson, C; Mjelde, E; Hevroy, K. |
| High-resolution records from IMAGES core MD95-2011 in the eastern Norwegian Sea provide evidence for relatively large- and small-scale high-latitude climate variability throughout the Holocene. During the early and mid-Holocene a situation possibly driven by consistent stronger westerlies increased the eastward influence of Arctic intermediate and near-surface waters. For the late Holocene a relaxation of the atmospheric forcing resulted in increased influence of Atlantic water. The main changes in Holocene climate show no obvious connection to changing solar irradiance, and spectral analysis reveals no consistent signature for any periodic behavior of Holocene climate at millennial or centennial timescales. There are, however, indications of consistent... |
| Tipo: Text |
Palavras-chave: Holocene; Climate; Nordic Seas; NAO; High resolution; Variability. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00224/33500/32119.pdf |
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| Dekov, Vesselin M.; Darakchieva, Valentina Y.; Billström, Kjell; Garbe-schönberg, C-dieter; Kamenov, George D.; Gallinari, Morgane; Dimitrov, Lyubo; Ragueneau, Olivier; Kooijman, Ellen. |
| Concentrations of a large set of major and trace elements, and Sr, Nd and Pb isotope ratios were measured in Holocene sediments cored in the western deep Black Sea in order to unravel: (1) the controls of element enrichment, and (2) sources of the detrital component. The transition of the basin from oxic to euxinic resulted in enrichment or depletion in a number of elements in the deep-sea sediments. Authigenic Fe enrichment appears to depend on the amount of Fe mobilized from the sediment through the benthic redox shuttle mechanism and free H2S in the water column (degree of “euxinization”). Manganese enrichment is controlled by diagenetic reactions within the sediment: the dissolution of Mn minerals, Mn2+ diffusion upward and reprecipitation. Barium... |
| Tipo: Text |
Palavras-chave: Anoxic; Black Sea; Element enrichment; Sr-Nd-Pb-isotopes; Holocene. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00590/70164/68171.pdf |
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| Crosta, X.; Debret, M.; Denis, D.; Courty, M. A.; Ther, O.. |
| Diatom data from a marine sediment core give insight on Holocene changes in sea- surface conditions and climate at high southern latitudes off Adelie Land, East Antarctica. The early to mid- Holocene was warmer than the late Holocene with a transition at similar to 4000 calendar years B. P. Sea ice was less present and spring- summer growing season was greater during the warm period relative to the cold one, thus limiting sea ice diatom production and favoring more open ocean diatom to develop. The long- term Holocene climatic evolution in East Antarctica is explained by a combination of a delayed response to local seasonal insolation changes coupled to the long memory of the Southern Ocean. Abrupt variations of the diatom relative abundances, indicating... |
| Tipo: Text |
Palavras-chave: Antarctica; Sea ice; Holocene; Insolation; Thermohaline circulation. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00235/34642/33044.pdf |
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| Caniupan, Magaly; Lamy, Frank; Lange, Carina B.; Kaiser, Jerome; Kilian, Rolf; Arz, Helge W.; Leon, Tania; Mollenhauer, Gesine; Sandoval, Susana; De Pol-holz, Ricardo; Pantoja, Silvio; Wellner, Julia; Tiedemann, Ralf. |
| Here we provide three new Holocene (11-0 cal ka BP) alkenone-derived sea surface temperature (SST) records from the southernmost Chilean fjord region (50-53 degrees S). SST estimates may be biased towards summer temperature in this region, as revealed by a large set of surface sediments. The Holocene records show consistently warmer than present-day SSTs except for the past similar to 0.6 cal ka BP. However, they do not exhibit an early Holocene temperature optimum as registered further north off Chile and in Antarctica. This may have resulted from a combination of factors including decreased inflow of warmer open marine waters due to lower sea-level stands, enhanced advection of colder and fresher inner fjord waters, and stronger westerly winds. During... |
| Tipo: Text |
Palavras-chave: Holocene; Alkenones; Sea-surface temperature; Fjords; Chile. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00290/40088/39292.pdf |
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| Denis, Delphine; Crosta, X; Zaragosi, S; Romero, O; Martin, B; Mas, Virginie. |
| A 40 m long sediment core covering the 1000-9600 years BP period was retrieved from the Dumont d'Urville Trough off Adelie Land, East Antarctica, during the MD 130-Images X-CADO cruise. This sedimentary sequence allows the documentation of changes in climate seasonality during the Holocene. Here we show preliminary results of diatom communities, lithic grain distribution and titanium content measured on two 30 cm long sequences of thin sections. The two sequences originate from two different climate regimes, the colder Neoglacial and the warmer Hypsithermal. Proxies were measured at microscale resolution on 25 laminations for the Neoglacial and 14 laminations for the Hypsithermal. The two sequences reveal alternating light-green and dark-green laminae.... |
| Tipo: Text |
Palavras-chave: East Antarctica; Sea ice; Seasonality; Diatom ooze; Laminated sediments; Holocene; Adelie Land. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2275.pdf |
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| Cortes Sanchez, Miguel; Jimenez Espejo, Francisco J.; Simon Vallejo, Maria D.; Gibaja Bao, Juan F.; Carvalho, Antonio Faustino; Martinez-ruiz, Francisca; Rodrigo Gamiz, Marta; Flores, Jose-abel; Paytan, Adina; Lopez Saez, Jose A.; Pena-chocarro, Leonor; Carrion, Jose S.; Morales Muniz, Arturo; Rosello Izquierdo, Eufrasia; Riquelme Cantal, Jose A.; Dean, Rebecca M.; Salgueiro, Emilia; Martinez Sanchez, Rafael M.; De La Rubia De Gracia, Juan J.; Lozano Francisco, Maria C.; Vera Pelaez, Jose L.; Llorente Rodriguez, Laura; Bicho, Nuno F.. |
| New data and a review of historiographic information from Neolithic sites of the Malaga and Algarve coasts (southern Iberian Peninsula) and from the Maghreb (North Africa) reveal the existence of a Neolithic settlement at least from 7.5 cal ka BP. The agricultural and pastoralist food producing economy of that population rapidly replaced the coastal economies of the Mesolithic populations. The timing of this population and economic turnover coincided with major changes in the continental and marine ecosystems, including upwelling intensity, sea-level changes and increased aridity in the Sahara and along the Iberian coast. These changes likely impacted the subsistence strategies of the Mesolithic populations along the Iberian seascapes and resulted in... |
| Tipo: Text |
Palavras-chave: Abrupt climate change; Mesolithic-Neolithic transition; South Iberia; Holocene; Migration; Hunter-fisher-gatherers; Paleoceanography. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00266/37678/35767.pdf |
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| Railsback, L. Bruce; Brook, George A.; Liang, Fuyuan; Marais, Eugene; Cheng, Hai; Edwards, R. Lawrence. |
| Stalagmite Orum-1 from a cave near Orumana in northwestern Namibia provides a multi-proxy record of regional drying with increasing global-scale warmth over the last 47 kyr, in a region with few long well-dated location specific paleoclimate records. Data from Stalagmite Orum-1 include carbon and oxygen stable isotope ratios, proportions of aragonite and calcite, pronouncedly differing petrographic fabrics, positions of layer-bounding surfaces, variation in layer-specific width, and changes in layer thickness, all of which combine to support change from wetter to drier conditions. Combined with fourteen U-Th ages, they suggest that climate was wetter in northwestern Namibia during globally cold MIS 3 than it is today, and with more grass than is present... |
| Tipo: Text |
Palavras-chave: Namibia; Paleoclimate; Pleistocene; Holocene; Savanna; Stalagmite. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53213/54862.pdf |
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| Andersen, Nils; Lauterbach, Stefan; Erlenkeuser, Helmut; Danielopol, Dan L.; Namiotko, Tadeusz; Huels, Matthias; Belmecheri, Soumaya; Dulski, Peter; Nantke, Carla; Meyer, Hanno; Chapligin, Bernhard; Von Grafenstein, Ulrich; Brauer, Achim. |
| The so-called 8.2 ka event represents one of the most prominent cold climate anomalies during the Holocene warm period. Accordingly, several studies have addressed its trigger mechanisms, absolute dating and regional characteristics so far. However, knowledge about subsequent climate recovery is still limited although this might be essential for the understanding of rapid climatic changes. Here we present a new sub-decadally resolved and precisely dated oxygen isotope (5180) record for the interval between 7.7 and 8.7 ka BP 10(3) calendar years before AD 1950), derived from the calcareous valves of benthic ostracods preserved in the varved lake sediments of pre-Alpine Mondsee (Austria). Besides a clear reflection of the 8.2 ka event, showing a good... |
| Tipo: Text |
Palavras-chave: Holocene; Palaeoclimatology; Europe; Stable isotopes; 8.2 ka event; Lake sediments. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00504/61597/65876.pdf |
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| Registros recuperados: 105 | |
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