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Budziak, D; Schneider, Rr; Rostek, F; Muller, Pj; Bard, E; Wefer, G. |
We here present records of total organic carbon (TOC) and C-37 alkenones, used as indicators for past primary productivity, from the western (WAS) and eastern Arabian Sea (EAS). New data from an open ocean site of the WAS upwelling area are compared with similar records from Ocean Drilling Program (ODP) Site 723 from the continental margin off Oman and MD 900963 from the EAS. These records together with other proxies used to reconstruct upwelling intensity, indicate periods of high productivity in tune with precessional forcing. On the basis of their phase relationship to boreal summer insolation they can be divided into three groups: in the WAS differences between monsoonal proxies (1) and productivity (2) document a combined signal of moderate SW monsoon... |
Tipo: Text |
Palavras-chave: Indian Ocean; Marine organic chemistry; Upwelling and convergences. |
Ano: 2000 |
URL: https://archimer.ifremer.fr/doc/00220/33160/31672.pdf |
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Delaygue, G; Bard, E; Rollion, C; Jouzel, J; Stievenard, M; Duplessy, Jc; Ganssen, G. |
We analyze the surface sigma O-18 - salinity relationships of the Bay of Bengal and the Arabian Sea, in the northern Indian Ocean, known for their contrasting hydrological conditions. New measurements of these tracers show a very low sigma O-18 - salinity slope associated with the strong dilution in the Bay of Bengal, but a slope more typical of this latitude in the Arabian Sea. Although this region is marked by a complex monsoonal regime, numerical modeling using a box model and a general circulation model is able to capture the sigma O-18 - salinity slope and its geographical variation. Both models clearly show that the low sigma O-18 - salinity slope is due to the evaporation-minus-precipitation balance, with an important contribution of the continental... |
Tipo: Text |
Palavras-chave: Indian Ocean; Ocean/atmosphere interactions; Paleoclimatology; Stable isotopes. |
Ano: 2001 |
URL: https://archimer.ifremer.fr/doc/00221/33225/31800.pdf |
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Sicre, Ma; Bard, E; Ezat, U; Rostek, F. |
The C(37)-C(39) alkenones were quantified in suspended particulate matter obtained from the surface waters of the North Atlantic, including the Nordic seas, over a temperature range of 4degrees20 C. U(37)(K') values were linearly correlated to temperature over the entire range covered by our data set, i.e., 420 C (U(37)(K') = 0.027T + 0.036, r(2) = 0.97). The compilation of water column data from the Atlantic, Pacific, and Southern Ocean and Mediterranean Sea suggests that the linear model may not be the best function for fitting U(37)(K') and in situ temperature values. It also shows that suspended matter data from warm waters (T >20degreesC) are still needed to constrain the equation of the global curve. High abundances of C(37: 4) were found in the... |
Tipo: Text |
Palavras-chave: Alkenones; Paleotemperature; Calibration; Atlantic Ocean; Plankton; Geochemistry; Marine geochemistry; Global change; Biogeochemical processes (4805); Oceanography; Paleoceanography. |
Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33393/31866.pdf |
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Bard, E; Menot-combes, G; Rostek, F. |
In this paper, we present updated information and results of the radiocarbon records based on Polynesian corals and on Iberian Margin planktonic foraminifera. The latter record was first published by Bard et al. (2004a,b), with the subsequent addition of some data by Shackleton et al. (2004). These data sets are compared with the IntCal98 record (Stuiver et al. 1998) and with data sets based on other archives, such as varves of Lake Suigetsu (Kitagawa and van der Plicht 1998, 2000), speleothems from the Bahamas (Beck et al. 2001), and Cariaco sediments (Hughen et al. 2004). Up to 26,000 cal BP, the Iberian Margin data agree within the errors of the other records. By contrast, in the interval between 33,000 and 41,000 cal BP, the Iberian Margin record runs... |
Tipo: Text |
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Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00226/33727/32132.pdf |
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Eris, K; Ryan, W; Cagatay, M; Sancar, U; Lericolais, Gilles; Menot, G; Bard, E. |
High-resolution reflection seismic profiles with core analyses of sedimentary sequence near the Sea of Marmara (SoM) entrance to the Strait of İstanbul (SoI, Bosphorus) provide detailed record of sealevel changes since the Late Glacial Maximum (LGM). The sequence is deposited over the LGM erosional surface at a maximum depth of -105 m. It includes seven seismic units that can be confidently correlated with 14C-dated sedimentary units in the cores. Unit 6 represents levee deposits of the paleo-SoI channel that was deposited by a Black Sea outflow during 11.2-10.6 kyr BP. The reflection surfaces at base of Unit 5 and 4 correspond to wave-cut terraces at -71and -63 m, respectively, and are estimated to be 10.6 and 9.8 kyr BP. The seismic Unit 2, overlaying a... |
Tipo: Text |
Palavras-chave: Sapropel; Delta; Marmara Sea; Holocene; Sea level; Seismic stratigraphy. |
Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3574.pdf |
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