Institute Fondamental dAfrique Noire Cheikh Anta Diop

Dakar, Senegal

Institute Fondamental dAfrique Noire Cheikh Anta Diop

Dakar, Senegal
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Baumgartner R.J.,University of Western Australia | Fiorentini M.L.,University of Western Australia | Lorand J.-P.,CNRS Nantes Laboratory of Planetology and Geodynamics | Baratoux D.,French National Center for Scientific Research | And 5 more authors.
Geochimica et Cosmochimica Acta | Year: 2017

The shergottite meteorites are ultramafic to mafic igneous rocks whose parental magmas formed from partial melting of the martian mantle. This study reports in-situ laser ablation inductively coupled plasma mass spectrometry analyses for siderophile and chalcophile major and trace elements (i.e., Co, Ni, Cu, As, Se, Ag, Sb, Te, Pb, Bi, and the highly siderophile platinum-group elements, PGE: Os, Ir, Ru, Rh, Pt and Pd) of magmatic Fe-Ni-Cu sulfide assemblages from four shergottite meteorites. They include three geochemically similar incompatible trace element- (ITE-) depleted olivine-phyric shergottites (Yamato-980459, Dar al Gani 476 and Dhofar 019) that presumably formed from similar mantle and magma sources, and one distinctively ITE-enriched basaltic shergottite (Zagami). The sulfides in the shergottites have been variably modified by alteration on Earth and Mars, as well as by impact shock-shock related melting/volatilization during meteorite ejection. However, they inherit and retain their magmatic PGE signatures. The CI chondrite-normalized PGE concentration patterns of sulfides reproduce the whole-rock signatures determined in previous studies. These similarities indicate that sulfides exerted a major control on the PGE during shergottite petrogenesis. However, depletions of Pt (and Ir) in sulfide relative to the other PGE suggest that additional phases such discrete Pt-Fe-Ir alloys have played an important role in the concentration of these elements. These alloys are expected to have enhanced stability in reduced and FeO-rich shergottite magmas, and could be a common feature in martian igneous systems. A Pt-rich PGM was found to occur in a sulfide assemblage in Dhofar 019. However, its origin may be related to impact shock-related sulfide melting and volatilisation during meteorite ejection. In the ITE-depleted olivine-phyric shergottites, positive relationships exist between petrogenetic indicators (e.g., whole-rock Mg-number) and most moderately to strongly siderophile and chalcophile elements in sulfides. These variations extend to incompatible elements like Te and Pd. The whole-rock concentrations of Pd derived from mass-balance calculations decrease by one order of magnitude in the order Y-980459, DaG 476 and Dhofar 019, and broadly overlap the trends in previously published whole-rock analyses. Mantle heterogeneities, and the timing of sulfide saturation as function of mantle melting and/or magma fractionation following ascent from the mantle, may have been the controlling factors of the siderophile and chalcophile element systematics in the analyzed shergottites. © 2017 Elsevier Ltd

Azzouz K.,University of Carthage | Diatta Y.,Institute Fondamental dAfrique noire Cheikh Anta Diop | Mansour S.,University of Carthage | Boumaiza M.,University of Carthage | And 2 more authors.
Acta Ichthyologica et Piscatoria | Year: 2011

Two specimens of the west African goatfish, Pseudupeneus prayensis (Cuvier, 1829), were found for the first time off the Tunisian coast, in northern area. They constituted the third Mediterranean record of this fish. Both specimens were studied and described, and some biological observations were reported. Same taxonomic characters were concomitantly determined on two west African goatfish caught off the coast of Senegal, for comparison. The occurrence of Pseudupeneus prayensis in the area and the Mediterranean Sea is discussed and commented.

Ben Souissi J.,Tunis el Manar University | Diatta Y.,Institute Fondamental dAfrique Noire Cheikh Anta Diop | Gargouri Ben Abdallah L.,Institute Nationa Agronomique Of Tunisie | Capape C.,Montpellier University
Cahiers de Biologie Marine | Year: 2011

A Monrovian surgeonfish, Acanthurus monroviae Steindachner, 1892, was found for the first time off the Tunisian coast, in the Gulf of Tunis, northern Tunisia. The specimen is described with morphometric measurements, meristic counts and some biological observations. The occurrence of A. monroviae in the area and the Mediterranean Sea is discussed and commented.

Chaabout S.,Hassan II University | Chennaoui Aoudjehane H.,Hassan II University | Reimold W.U.,Leibniz Institute for Evolution and Biodiversity Science | Reimold W.U.,Humboldt University of Berlin | And 4 more authors.
Journal of African Earth Sciences | Year: 2015

The current terrestrial impact crater record includes 188 accepted structures ( and Ferrière et al., 2015). This number continues to increase slowly but quite regularly. The heterogeneous distribution of impact structures is strongly influenced by the knowledge about impact cratering of exploration geologists, who have to be familiar with the possible field evidence for impact structures - and ultimately with the recognition criteria accepted for confirmation of new impact structures. For remote and poorly explored areas, satellite imagery is a powerful tool to identify circular structures that, at all scales, could be considered possible candidates for impact structures. Here, we present the results of a first systematic survey of circular structures over the Moroccan surface area (a total of 710,850 km2) using the imagery available through the Google-Earth software. Structures whose origins could not be elucidated from available geological data were then visited to determine their origin (impact or non-impact). Thirteen sites with one or more circular structures were investigated but none of them could be associated with an impact event. Instead, our results illustrate the diversity of geological processes that can produce circular structures, including magmatic and tectonic processes, bioconstruction, and even anthropogenic activity. It also demonstrates that circular structures are very common in surface imagery of the Earth but are generally not associated with impact events. This result questions whether this simple approach for the search of impact structures should be extended to other parts of the world. It also emphasizes that remote sensing imagery should not be used in isolation of other data. © 2015 Elsevier Ltd.

Capape C.,Montpellier University | Diatta Y.,Institute Fondamental dAfrique Noire Cheikh Anta Diop | Ndiaye P.,Institute Fondamental dAfrique Noire Cheikh Anta Diop | Reynaud C.,Montpellier University | Oddone M.C.,Federal Foundation University of Rio Grande
Ciencias Marinas | Year: 2010

A total of 483 specimens (236 males and 247 females) of the brown ray Raja miraletus were collected off the coast of Senegal (eastern tropical Atlantic). The hepatosomatic index (HSI) and gonadosomatic index (GSI) were calculated in both males and females, and the oviducosomatic index (OSI) in females. Both HSI and GSI increased significantly with specimen size and the three maturity stages considered (juveniles, subadults, and adults). The monthly HSI of adult males did not show significant variations throughout the year. In contrast, the HSI of adult females, GSI of both adult males and females, and OSI of females showed significant variations throughout year. This suggests that monthly variations occurred in the production of gonadal products even though vitellogenetic activity was observed throughout the year.

Ali M.,Tishreen University | Diatta Y.,Institute Fondamental Dafrique Noire Cheikh Anta Diop | Alkusairy H.,Tishreen University | Saad A.,Tishreen University | Capape C.,Montpellier University
Journal of Ichthyology | Year: 2016

This paper reports the first record of Red Sea goatfish Parupeneus forsskali (Fourmanoir and Guézé, 1976) from the Syrian coast. This record confirms the occurrence of the species in the Levant Basin. However, no sufficient data were carried out to date to support that a population is at present substantially established in the same area. © 2016, Pleiades Publishing, Ltd.

Diatta Y.,Institute Fondamental dAfrique noire Cheikh Anta Diop | Reynaud C.,Montpellier University | Capape C.,Montpellier University
Journal of Ichthyology | Year: 2013

This paper gives the description of a striped panray Zanobatus schoenleinii (Müller and Henle, 1841) presenting the first case of albinism recorded in this species. The specimen was an adult male captured at low depth off the coast of Senegal (eastern tropical Atlantic). Comments on albinism in fishes are provided in this paper, especially all cases reported in batoid species. © 2013 Pleiades Publishing, Ltd.

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