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| Blanc, G; Boulegue, J; Gieskes, Jm. |
| We report here our findings on the chemistry of methane, manganese and chloride dissolved in the interstitial water of the Barbados accretionary complex. The decollement separating the subduction plate from the accretionary wedge is geochemically characterized by high methane and manganese and low chloride concentrations relative to buried seawater. Sandstone layers occurring below the decollement and the compressive structures recording some of the earliest effects of offscraping are also characterized by similar anomalies. A fluid with the same characteristics is also found six kilometres to the east of the deformation front within the oceanic plate. High manganese concentration and low chlorinity also occur in the pore water of the offscraped sediment... |
| Tipo: Text |
Palavras-chave: BARBADOS ACCRETIONARY COMPLEX; INTERSTITIAL WATER; CHEMICAL COMPOSITION; ADVECTION; DIAGENESIS. |
| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00101/21262/18873.pdf |
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| Macquartmoulin, C; Patriti, G. |
| Increased offshore advection of migratory neritic plankton may occur by the pathway of nearshore submarine canyons. The nocturnal distribution of migratory bentho-hyponeustonic crustacea was investigated in the axis and on both sides of three submarine canyons, over the continental shelf and slope of the northwestern Mediterranean. The three canyons arc frequently exposed to strong northerly and northwesterly winds blowing seaward. A horizontal surface haul and a vertical haul from bottom to surface were successively achieved with an OMORI plankton net over each depth, from the isobath 50 m to more than 1000 m, in the middle of the night. The Mysidacea Anchialina agilis, Haplostylus lobatus, Siriella clausii, Siriella norvegica and Leptomysis gracilis, and... |
| Tipo: Text |
Palavras-chave: PLANKTON; CANYONS; ADVECTION; MYSIDACEA; ISOPODA. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00099/21045/18671.pdf |
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| Blanc, G; Doussan, C; Thomas, C; Boulegue, J. |
| We present a non-steady-state diffusion and advection model that describes the distribution of methane, manganese and silica concentrations versus depth at sites 671, 676, and 672 of ODP Leg 110 through an oceanic sedimentary pile undergoing horizontal shortening by means of thrust-faults and folds. The model suggests that the distribution of these chemical components above and below fluid flow conduits is controlled by molecular diffusion. Upward fluid advection from the pathways to the surrounding sediments appears to be without significance for this environment (about 1.10(-11) m.s-1, i.e. almost-equal-to 0.3 mm.yr-1). Estimates of the time necessary to produce the diffusion profiles indicate that average ages of the chemical anomalies increase from... |
| Tipo: Text |
Palavras-chave: NUMERICAL MODEL; INTERSTITIAL WATER; DIFFUSION; ADVECTION; DIAGENESIS. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00100/21137/18757.pdf |
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| Colin, C. |
| The wind, temperature and current data collected during the joined French-USA FOCAL/SEQUAL programme carried in the equatorial Atlantic band in 1983 and 1984, allowed for the first time a simultaneous study of both the equatorial and coastal (5-degrees-N) upwellings along 4-degrees-W. At the equator, the decreases of both the surface temperature and the depth of the thermocline in boreal summer are correlated with the zonal component of the local windstress in the period band 1-2 months. This corresponds to the time required by the thermocline to lift up at 0-4-degrees-W in the presence of an easterly wind. The local wind cannot however explain the entire vertical variability of the thermal structure at 0-4-degrees-W. The correlation function shows in... |
| Tipo: Text |
Palavras-chave: GULF OF GUINEA; UPWELLING; EQUATOR; ADVECTION; DIFFUSION. |
| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00101/21252/18865.pdf |
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