[Show abstract][Hide abstract] ABSTRACT: L'analyse stratonomique et micropaléontologique des affleurements de marnes aptiennes du secteur du hameau de La Tuilière, près de Saint-Saturnin-lès-Apt (Vaucluse, SE France), nous a permis de reconstituer une série continue, épaisse de près de 120 m, comprenant les termes supérieurs de l'Aptien inférieur (Bédoulien) et la partie inférieure de l'Aptien moyen (Gargasien). Ces niveaux n'avaient jamais pu être observés avec une telle continuité dans la région de Gargas, stratotype historique de l'Aptien
Carnets de Geologie 02/2006; DOI:10.4267/2042/4565 · 0.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A stratonomic and micropaleontological analysis of the Aptian marls cropping out in the La Tuilière area near Saint-Saturnin-lès-Apt (Vaucluse, SE France), enabled us to reconstitute a continuous succession almost 120 m thick, that includes the upper terms of the Lower Aptian (Bedoulian) and the lower part of the Middle Aptian (Gargasian). These levels had never before been observed with such continuity in the Gargas region, the Aptian historical stratotype.
Carnets de Geologie 02/2006; DOI:10.4267/2042/4564 · 0.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Ostracode assemblages have been collected from sediments dredged in the lagoon of Mayotte Island in order to study effects of mudflows from land to lagoonal zones due to anthropisation. Two main facies occur: bioclastic sandy bottoms in the external part and muddy deposits which progressively invade the major part of coastal bays and proximal lagoonal zones. Previous geological analyses are available dealing with some micropalaeontological (foraminifera) and sedimentological aspects. A systematic approach of the ostracode content is proposed within the same context; records obtained constitute a preliminary account concerning this area; nevertheless, a few data already given in the selected bibliography may be used. In such sedimentary environments characterized by a high evolutionary rate, the knowledge of present-day assemblages and their qualitative/quantitative composition will be of great interest because they may be considered as reference for the future. One of the prior applications will be to put in a prominent position the effect of occasional variations of physico-chemical parameters related with the development of human activities. The ostracode fauna is composed of thirty-nine recorded species belonging to thirty-five genera (four indetermined) and ranging mainly into the Cytheracea and Bairdiacea; Cypridacea are less common. Poorly local documentation and occurrence of rare and/or badly preserved specimens does not permit an accurate ostracode check-list. Accordingly, many species are left in open nomenclature. Within the two sedimentary type-deposits, ostracode assemblages show many qualitative differences; diversity is maximum in medium mud-content areas (transitional facies between sands and pure muds). From a quantitative point of view, it is noteworthy the more important scarcity of microfaunas on bioclastic (shelly) sands and several well-muddy substrates. An assessment is made of the biogeographic point of view; mahoran microfaunas show strong affinities with those of North Madagascar and Reunion Island. Common species have been described or located in the Western Pacific Ocean, especially Australia. Relationships with South African coasts are not clearly demonstrated.
[Show abstract][Hide abstract] ABSTRACT: In the two areas of Lobito-Benguela and Mossamedes, deposits of distinct Holocene, mid-Würmian, Eemian and Mindel-Riss interglacial shorelines were radiometrically dated using 14C and 230Th/234U and 231Pa/231U ratios. Deposits of different ages were found on the same terraces: the morphology of these terraces is the result of repeated erosion at different times by successive sea levels at similar elevations. The average rate of uplift clearly increased since the Riss; the Holocene appears to be a period of markedly increased epeirogenic activity. Also vertical movement appears more intense in the Lobito-Benguela area than near Mossamedes. The intensity of uplift appears to be associated with epicentres oriented towards the west-southwest, that is parallel to the axis of the Walvis ridge; the direction is outlined by diverse Mesozoïc effusive volcanic centres.