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| Regoli, Fabienne; De Garidel-thoron, Thibault; Tachikawa, Kazuyo; Jian, Zhiming; Ye, Liming; Droxler, Andre W.; Lenoir, Guillaume; Crucifix, Michel; Barbarin, Nicolas; Beaufort, Luc. |
| The depth of equatorial Pacific thermocline is diagnostic of the main modes of tropical climates. Past estimates of Pacific thermocline dynamics have been reconstructed either for the Last Glacial Maximum or on longer timescales at low resolution. Here we document a new high-resolution set of reconstructed past sea surface and subsurface waters temperatures from the southwestern subequatorial Pacific, core MD05-2930, in the Gulf of Papua, over the last 800 ka. We used two morphotypes of Globigerinoides ruber known to live at different water depths to reconstruct past stratification. We estimated calcification temperature of each morphotypes by Mg/Ca paleothermometry. Our subequatorial Pacific thermocline paleotemperature record indicates a response of the... |
| Tipo: Text |
Palavras-chave: Equatorial Pacific; Thermocline; Pleistocene. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00295/40572/39477.pdf |
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| Labatut, M.; Lacan, F.; Pradoux, C.; Chmeleff, J.; Radic, A.; Murray, J. W.; Poitrasson, F.; Johansen, A. M.; Thil, F.. |
| This work presents iron isotope data in the western equatorial Pacific. Marine aerosols and top core margin sediments display a slightly heavy Fe isotopic composition (Fe-56) of 0.330.11 (2SD) and 0.140.07, respectively. Samples reflecting the influence of Papua New Guinea runoff (Sepik River and Rabaul volcano water) are characterized by crustal values. In seawater, Fe is mainly supplied in the particulate form and is found with a Fe-56 between -0.49 and 0.34 +/- 0.07 parts per thousand. The particulate Fe seems to be brought mainly by runoff and transported across continental shelves and slopes. Aerosols are suspected to enrich the surface Vitiaz Strait waters, while hydrothermal activity likely enriched New Ireland waters. Dissolved Fe isotopic ratios... |
| Tipo: Text |
Palavras-chave: Iron isotopes; Particles; Equatorial Pacific; Papua New Guinea; Seawater; GEOTRACES. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00290/40074/39162.pdf |
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| Yamazaki, T; Oda, H. |
| We have conducted a paleomagnetic study of six sediment cores taken from the equatorial Pacific, three from the West Caroline Basin and three from the Manihiki Plateau, in order to make a relative paleointensity stack during the Matuyama and late Gauss Chrons. The age of the bottom of the cores ranges from 1.2 to 3.0 Ma. The sediments show little downcore changes in the proxies of magnetic grain size and mineralogy and are hence suitable for estimating relative paleointensity. The age of the cores is controlled by correlating variations in magnetic concentration ( magnetic susceptibility and/or anhysteretic remanent magnetization (ARM)) to target oxygen-isotope (delta(18)O) curves. All cores from the Manihiki Plateau show an upward decrease of the natural... |
| Tipo: Text |
Palavras-chave: Equatorial Pacific; Excursion; Orbital modulation; Paleointensity; Paleomagnetism. |
| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00232/34285/32650.pdf |
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| Le Borgne, R; Rodier, M; Le Bouteiller, A; Murray, Jw. |
| Observations made during a "La Nina" situation (April-May 1996) in the equatorial Pacific upwelling, between 165 degrees E and 150 degrees W, show the classic deepening of hydrological isolines from east to west, resulting in zonal gradients for surface temperature and macronutrients. However, contrasting with such a gradient, no clear zonal variation could be seen for integrated planktonic biomasses and carbon fluxes, namely: chlorophyll a, bacterial abundances, particulate organic phosphorus, mesozooplankton ash free dry weight, primary production, and the sinking flux of particulate organic carbon (POC). Moreover, mean values of these parameters along the zonal equatorial transect, are not significantly different from those of a 7-day-long time series... |
| Tipo: Text |
Palavras-chave: Pacifique équatorial; Variabilité zonale; Plancton; Sédimentation de carbone; Production primaire; Equatorial Pacific; Zonal variations; Plankton; Carbon sinking flux; Primary production. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00325/43629/43254.pdf |
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| Maenhaut, W.; Raemdonck, H.; Selen, A.; Van Grieken, R.; Winchester, J.W.. |
| By using a polyester sailboat as sampling platform, a series of duplicate aerosol samples was collected by cascade impactors on a trip from Panama to Tahiti in 1979. Elemental analysis mainly by particle-produced X-ray emission (PIXE) indicated, in the samples collected between Panama and the Galapagos Islands, the presence of a substantial crustal component (0.4 µg/m³), fine Cu (0.4 ng/m³ and Zn (0.6 ng/m³), and excess fine S and K (100 and 2.4 ng/m³, respectively in addition to the major sea salt elements. The crustal component and fine Cu and Zn are suggested to result from natural continental sources (i.e., eolian dust transport from the American continents and perhaps geothermal emissions). Samples collected west of the Galapagos Islands in the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aerosols IS; Equatorial Pacific. |
| Ano: 1983 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3398 |
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