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| Pierre, Catherine; Fouquet, Yves. |
| Submersible investigations with the ROV Victor 6000 of some pockmark structures on the seafloor of the Congo deep-sea fan have shown that they are active venting sites of methane-rich fluids, associated with abundant fauna and carbonate crusts. Moreover, methane hydrates have been observed both outcropping and deep in the sediments in the centre of the "Regab" giant pockmark. Authigenic carbonates, mostly calcite sometimes mixed with aragonite, are cementing the sedimentary matrix components and fauna; diatoms are abundant but only as moulds, indicating that biogenic silica dissolution occurred in situ synchronous with carbonate precipitation. The occurrence of diagenetic barite and pyrite in some carbonate crusts demonstrates that they can be formed... |
| Tipo: Text |
Palavras-chave: Oxygen isotopes; Carbon isotopes; Congo deep sea fan; Gas hydrate; Methane seep; Authigenic carbonate. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2608.pdf |
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| Dannenmann, S; Linsley, Bk; Oppo, Dw; Rosenthal, Y; Beaufort, L. |
| We have generated a new high-resolution record of variations in planktonic foraminiferal oxygen isotopes (delta(18)O) and Mg/Ca from a sediment core (IMAGES 97-2141) in the Sulu Sea located in the Philippine archipelago of western tropical Pacific. This record reveals distinct, suborbital-scale delta(18)O changes, most notably during Marine Isotope Stage 3 (MIS3) (similar to30,000 to 60,000 years B.P.). The amplitudes of these delta(18)O fluctuations (0.4 to 0.7parts per thousand) exceed that which can be attributed to sea level changes and must be due to changes in sea surface conditions. In the same interval, variations in planktonic foraminifera Mg/Ca suggest that suborbital surface ocean temperature variations of 1 to 1.5degreesC in the Sulu Sea were... |
| Tipo: Text |
Palavras-chave: Paleoceanography; Isotope stage 3; SE Asian Monsoon; Mg/Ca; Oxygen isotopes; Millennial-scale climate change; Paleoceanography; Climate dynamics. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00226/33681/32046.pdf |
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| Xuan, Chuang; Channel, James E. T.; Hodell, David A.. |
| The sediment sequence from Integrated Ocean Drilling Program (IODP) Site U1304 (53 degrees 03.40'N, 33 degrees 31.78'W; water depth, 3024 m) on the southern Gardar Drift, North Atlantic Ocean, covers the last similar to 1.8 Myr with a mean sedimentation rate of similar to 15 cm/kyr. At Site U1304, paleomagnetic directional and relative paleointensity (RPI) records have been generated for the last similar to 1.5 Myr, and benthic oxygen isotope data for the last similar to 1 Myr. The age model for Site U1304 was established by matching 6180 and RPI data to calibrated reference records. Prominent intervals of diatom mats at Site U1304 are associated with the latter stages of interglacial marine isotope stages (MIS) 9, 11, 13, 15, 21, 27 and 35, and with the... |
| Tipo: Text |
Palavras-chave: Quaternary; North Atlantic; Relative paleointensity; Magnetic excursions; Oxygen isotopes; Diatoms; IODP Site U1304. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53238/83373.pdf |
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| Jean-baptiste, Philippe; Fourre, Elise; Charlou, Jean-luc; Donval, Jean-pierre; Correge, Thierry. |
| Historical descriptions of the Clipperton lagoon appear to converge on the fact that it became isolated from the surrounding ocean around 1858. Since then, because of the high precipitation rate which largely exceeds evaporation in this region of the eastern tropical Pacific, a brackish lens has formed on top of the saline oceanic waters. In 1980, literature data show that the thickness of this water body was reaching 14 m. During the 2005 Etienne's Clipperton expedition, we collected lagoon water on two vertical profiles. Salinity, delta O-18 and tritium analyses were performed on these samples with the objective of gaining further insight into the lagoon hydrology and age of the deep waters. The upper 15 m were characterized by low salinities (5.4 +/-... |
| Tipo: Text |
Palavras-chave: Oxygen isotopes; Tritium; Enclosed lagoon hydrology; Clipperton atoll. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6457.pdf |
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