Consulta: subjectFacets:"Glacial"
Registros recuperados: 7
Data/hora: 02/06/2024 15:56:50

Hydrological changes in the Mediterranean Sea over the last 30,000 years
Provedor de dados: 5
Autores: Essallami, L.; Sicre, M. A.; Kallel, N.; Labeyrie, L.; Siani, G.
Sea surface temperatures were reconstructed over the last 30,000 years from alkenone paleothermometry (SST-(alk)) and planktonic foraminifera assemblages using the Modern Analog Technique (MAT) (SST-(foram)) along two cores of the Mediterranean Sea: MD84-632 (Levantine basin) and MD04-2797 (Siculo-Tunisian Strait). Oxygen isotope of planktonic foraminifera G. bulloides for core MD04-2797 and G. ruber for core MD84-632 were also determined. SST-alk in the Levantine basin indicate colder values at the Last Glacial Maximum (LGM) (similar to 14 degrees C) than earlier established from MAT, and a cooling amplitude of 6 degrees-7 degrees C, comparable to the central Mediterranean Sea. Climatic events such as the Younger Dryas (YD) and Heinrich events 1 and 2 (H1...
Tipo: Text
Palavras-chave: Paleoclimate; Glacial; Mediterranean; Alkenones; Foraminifera; Marine core.
Ano: 2007
URL: https://archimer.ifremer.fr/doc/00208/31954/30378.pdf

Dynamic storage of glacial CO2 in the Atlantic Ocean revealed by boron [CO32-] and pH records
Provedor de dados: 5
Autores: Chalk, T. B.; Foster, G. L.; Wilson, P. A.
The origin and carbon content of the deep water mass that fills the North Atlantic Basin, either Antarctic Bottom Water (AABW) or North Atlantic Deep Water (NADW) is suggested to influence the partitioning of CO2 between the ocean and atmosphere on glacial-interglacial timescales. Fluctuations in the strength of Atlantic meridional overturning circulation (AMOC) have also been shown to play a key role in global and regional climate change on timescales from annual to millennial. The North Atlantic is an important and well-studied ocean basin but many proxy records tracing ocean circulation in this region over the last glacial cycle are challenging to interpret. Here we present new B/Ca-[CO32-] and boron isotope-pH data from sites spanning the North...
Tipo: Text
Palavras-chave: Boron; Geochemistry; Palaeoceanography; Carbonate system; Glacial; Atlantic.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00496/60812/64631.pdf

A 27 kyr terrestrial biomarker record in the southern Indian Ocean
Provedor de dados: 5
Autores: Sicre, Marie-alexandrine; Labeyrie, Laurent; Ezat, Ullah; Mazaud, Alain; Turon, Jean-louis.
Terrestrial inputs were reconstructed using high molecular weight n-alkane concentrations recorded in the sub-Antarctic Indian Ocean core MD94-103 (45 degrees 35'S, 86 degrees 31'E, 3560 m) to examine regional changes in the atmospheric circulation over the last 27 kyr. This record was compared to the dust content of EPICA-Dome C ice and continental data from South Africa ( e. g., pollen sequences and isotope records in speleothems) to get a comprehensive understanding of atmospheric links between low and midlatitudes of the Indian Ocean. Terrestrial n-alkanes indicate higher glacial than Holocene inputs and marked glacial oscillations. Minimum values during the Last Glacial Maximum (LGM) are consistent with colder and drier climate and presumably caused...
Tipo: Text
Palavras-chave: Biomarker; Glacial; Indian Ocean; Marine sediments; Paleoclimate; Terrestrial.
Ano: 2006
URL: https://archimer.ifremer.fr/doc/00234/34547/33355.pdf

Fingerprint of tropical climate variability and sea level in sediments of the Cariaco Basin during the last glacial period
Provedor de dados: 5
Autores: Deplazes, Gaudenz; Meckler, A Nele; Peterson, Larry C.; Hamann, Yvonne; Aeschlimann, Beat; Günther, Detlef; Martínez‐garcía, Alfredo; Haug, Gerald H.
High‐resolution palaeorecords of climate are critical to improving current understanding of climate variability, its sensitivity and impact on the environment in the past and in the future. Sediments from the Cariaco Basin off the coast of Venezuela have proven to be sensitive recorders of tropical palaeoclimate variability down to an annual scale. However, the fingerprint of climate and sea level in the sediments of the last glacial period is still not completely understood. In this study, lamination analysis of sediments from the Cariaco Basin is extended to the last glacial period. Detailed sedimentological and geochemical analysis (laser ablation–inductively coupled plasma–mass spectrometry) reveals couplets of light‐coloured, terrigenous‐rich and...
Tipo: Text
Palavras-chave: Cariaco Basin; Caribbean Sea; Flooding events; Glacial; Interglacial climate; Sea-level oscillations; Varved marine sediments.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00471/58302/60827.pdf

Volcanoes and climate: the triggering of preboreal Jökulhlaups in Iceland
Provedor de dados: 5
Autores: Van Vliet-lanoë, Brigitte; Knudsen, Oskar; Guðmundsson, Agust; Guillou, Hervé; Chazot, Gilles; Langlade, Jessica; Liorzou, Celine; Nonnotte, Philippe.
The Early Holocene (12–8.2 cal ka) deglaciation and pulsed warming was associated in Iceland with two major generations of jökulhlaups around the Vatna ice-cap (Vatnajökull), at ca 11.4–11.2 cal ka and ca 10.4–9.9 cal ka, and major tephra emissions from the Grímsvötn and Bárðarbunga subglacial volcanoes. The earliest flood events were recorded inland during the Middle Younger Dryas and their deposits were overlain by the Early Preboreal Vedde Ash (11.8 cal ka). The first Holocene flood events (ca 11.4–11.2 cal ka) are issued from a glacial advance. The second, and major, set of floods was partly driven by the Erdalen cold events and advances (10.1–9.7 10Be ka) initially issued from the Bárðarbunga (10.4, 10.1–9.9 ka) and Grímsvötn volcanoes (Saksunarvatn...
Tipo: Text
Palavras-chave: Holocene; Deglaciation; Iceland; Geomorphology; Glacial; Flood; Sedimentology; Tephra; Glacio-isostatic rebound; Permafrost; Saksunarvatn event; Askja S.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00613/72489/74845.pdf

Atlantic Meridional Overturning Circulation during the Last Glacial and Deglacial: Inferences from the Atlantic Tropical Thermocline Temperature and Seawater Radiocarbon Activity
Provedor de dados: 5
Autores: Huang, Enqing.
This thesis aims to investigate variations of the last glacial and deglacial Atlantic Ocean circulation, with emphasize on the Atlantic deepwater ventilation rate during the Last Glacial Maximum (LGM). The highlights of the thesis are as the followings: (1) the modern frontal zone between the North Atlantic and the South Atlantic central waters off NW Africa shifted to the south during the last glacial and deglacial time periods. (2) The radiocarbon-based circulation age of the deep Atlantic (&gt; 1500 m) was estimated to be less than 400 years during the LGM, which was equal to or less than its pre-bomb value. Therefore, the LGM deep Atlantic was inferred to be well ventilated. (3) The abyssal Atlantic (below 2500 m) prior to the LGM was more depleted in...
Tipo: Text
Palavras-chave: Climate change; Ocean circulation; Atlantic Ocean; Glacial; Deglacial; Thermocline; Radiocarbon; Global carbon cycle; Foraminifera; Carbonate; Trace elements; Deep ocean ventilation rates.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00493/60446/63891.pdf

Abrupt climate variability during the last glacial and the late Holocene from the western tropical Pacific perspective
Provedor de dados: 5
Autores: Saikku, Reetta Maaria.
In Project I, Western tropical Pacific sea surface temperatures and Pacific Deep Water temperatures during Marine Isotope Stage 3 have been reconstructed from the δ18O and Mg/Ca of planktonic and benthic foraminifera from Marion Dufresne core MD98-2181. This 36m marine core was collected at 6.3°N from a water depth of 2114m. With sediment accumulation rates of up to 80cm/ky, it provides a decadally-resolved history of ocean variability during the last glacial period. Surface temperatures and salinities at this site varied in close association with millennial-scale atmospheric temperature swings at high northern latitudes as reflected in the GISP2 ice core. At times of colder atmospheric temperatures over Greenland, the western Pacific was more saline and...
Tipo: Text
Palavras-chave: Climate; Pacific; Tropical; Glacial; Holocene.
Ano: 2009
URL: https://archimer.ifremer.fr/doc/00495/60653/64150.pdf