Black Beauty

S’intéresser à la consommation de cosmétiques des femmes noires et métissées à Paris et à Berlin, c’est plonger au cœur de deux sociétés et de deux histoires migratoires, coloniales et postcoloniales. C’est s’interroger sur la présence (ou non) de modèles de beauté « de couleur » dans les médias nationaux, sur la disponibilité (ou non) d’une offre commerciale dédiée à cette beauté qui aurait pignon sur rue. En contrepoint, l’étude des pratiques du quotidien des femmes concernées permet d’analyser leurs mises en récit de soi. Aussi, la black beauty n’en finit-elle pas de bousculer les marchés pour affirmer sa place dans la ville et pour lutter contre les catégorisations sociales dont elle fait l’objet

Le concours Miss et Mister Sénégal-Mali aux Docks de Paris

« Allo – Allo - Allo, Puissanci - Sunu Puissanci. » Avant l’ouverture de la première édition Miss et Mister Sénégal-Mali qui a eu lieu le 17 novembre 2017 en région parisienne, le manager monsieur Aly vérifie les micros en répétant le nom du collectif qui organise cette initiative. Construit à partir de deux mots empruntés aux langues les plus usités au Sénégal et au Mali – l’un wolof (Sunu, « notre »), l’autre bambara (Puissanci, « puissance »), le nom de ce collectif entend promouvoir une b..

Continent elevation, mountains, and erosion : freeboard implications

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 114 (2009): B05410, doi:10.1029/2008JB006176.To the simplest approximation, Earth's continental crust is a floating aggregate on the planet's surface that is first attracted to subduction zones and, upon arrival, thickened by mountain building (then producing some extension). Thickened regions are thinned again by erosion. A comparison between 65 Ma and the present shows that the modern state is significantly more mountainous. An estimated average continental elevation increase relative to average ocean floor depth of about 54 m and sea level decrease relative to the ocean floor of about 102 m add up to a 156-m increase of continent elevation over sea level since 65 Ma. Both are affected most strongly by the roughly 1.7% continent surface area decrease caused by Cenozoic mountain building. This includes contributions from erosion. Volumes of sediments in deltas and submarine fans indicate an average thickness of 371 m deposited globally in the ocean basins since 65 Ma. This relatively large change of continent area over a short span of Earth history has significant consequences. Extrapolating, if continent area change exceeded 5% in the past, either severe erosion or flooded continents occurred. If continent elevation (freeboard) remains at the present value of a few hundred meters, the past continent-ocean area ratio might have been quite different, depending on earlier volumes of continental crust and water. We conclude that, along with the ages of ocean basins, continental crustal thickening exerts a first-order control on the global sea level over hundreds of million years

Crustal shortening and vertical strain partitioning in the Middle Atlas Mountains of Morocco

Copyright 1998, American Geophysical Union. See also: http://www.agu.org/pubs/crossref/1998/98TC01439.shtml; http://atlas.geo.cornell.edu/morocco/publications/gomez1998.htmThe NE-SW trending Middle Atlas Mountains of Morocco are obliquely oriented within the late Cenozoic regional stress field, resulting in deformation that is partitioned into strike-slip faulting and thrust-related folding. In the central Middle Atlas, thrusting is confined to a 20 km wide fold belt between two relatively rigid crustal blocks that are obliquely converging. We suggest that in addition to strain partitioning observed in plan view, a partitioning of deformation between the upper and lower crust may be necessary to reconcile estimated crustal thickening and horizontal shortening within the fold belt. Cross-section balancing based on field observations demonstrates a relatively modest amount of Cenozoic horizontal shortening (~ 4.7 km) normal to the fold belt producing 800 m of structural relief. Yet, the geophysical data suggest this contraction has not produced a significant crustal root beneath the fold belt; that is, the belt does not appear to be isostatically compensated. Assuming all horizontal shortening was accommodated by crustal thickening beneath the fold belt implies much greater thickening than is suggested by constraints on the preshortened crustal thickness. It thus appears that thickening does not accommodate all of the contraction. We suggest one possible solution: The upper crust shortens by thickening (faulting and folding), whereas the lower crust deforms laterally

Reconstructing ancient Mediterranean crossroads in Deronectes diving beetles

[Aim] To reconstruct the evolutionary history of a genus of freshwater beetle with a pan-Mediterranean distribution, to test classic hypotheses which proposed a Miocene origin for groups with high biodiversity in the Iberian and Anatolian peninsulas.[Location] Mediterranean basin.[Methods] We sequenced four mitochondrial and one nuclear gene from 51 specimens of 30 of the c. 60 extant species of Deronectes (Dytiscidae), all typical of mid-mountain streams from North Africa and Iberia over most of Europe to the Middle East. We used maximum likelihood, Bayesian probabilities with an a priori evolutionary rate and a dispersal–extinction–cladogenesis model to reconstruct their biogeographical history.[Results] Deronectes has two major lineages which originated in the mid Miocene; one including mostly eastern and another mainly western and central Mediterranean species. From these two areas, range expansions, mainly at the end of the Miocene and beginning of the Pliocene, resulted in the many species groups and some of the extant species of the genus. Most of the current diversity and distributions are, however, of Plio-Pleistocene origin, particularly in widespread European species.[Main conclusions] In line with traditional hypotheses, we found an ancient division between eastern and western Mediterranean lineages of Deronectes, likely resulting from the isolation of Europe west of the Alps from the Balkans and Anatolia during the early-middle Miocene. The history of the genus was strongly influenced by major geological and climatic events, with successive cycles of fragmentation and subsequent eastward and westward range expansions, resulting in a steady accumulation of species across the basin. Most of these range movements took place through the north side of the Mediterranean, with only local displacements in the south during the Messinian salinity crisis and a recent (Pleistocene) colonization of the Italian Peninsula, which remained largely submerged through most of the genus’ evolutionary history.D.G.V. has a FPI PhD grant from the Spanish Government. This work has been partly funded by projects CGL2010-15755 and CGL2013-48950-C2-1-P to I.R.Peer reviewe

Distribution of sedimentary rock types through time in a back-arc basin: A case study from the Jurassic of the Greater Caucasus (Northern Neotethys)

Abstract The evolution of sedimentary basins can be explored by analyzing the changes in their lithologies and lithofacies (i.e. predominant lithologies). The Greater Caucasus Basin, which was located at the northern margin of the Neotethys Ocean, represents a complete Sinemurian-Tithonian succession. A quantitative analysis of compiled datasets suggests that principal lithologies and lithofacies are represented by siliciclastics, shale and carbonates. The relative abundance of siliciclastics and shale decreased throughout the Jurassic, whereas that of carbonates increased. Evaporites are known from the Upper Jurassic, while volcaniclastics and volcanics, as well as coals, are known only in the Lower to Middle Jurassic. Siliceous rocks are extremely rare. Lithology and lithofacies proportions change accordingly. The Sinemurian-Bathonian sedimentary complex is siliciclastic-and-shale-dominated, whereas the Callovian-Tithonian sedimentary complex is carbonate-dominated. A major change in the character of sedimentation occurred during the Aalenian-Callovian time interval. Regional transgressions and regressions were more important controls of changes in the sedimentary rock proportions than average basin depth. Landward shoreline shifts were especially favorable for carbonate accumulation, whereas siliciclastics and shale were deposited preferentially in regressive settings. An extended area of the marine basin, its lower average depth, and a sharp bathymetric gradient favored a higher diversity of sedimentation. An orogeny at the Triassic-Jurassic transition was responsible for a large proportion of siliciclastics and extensive conglomerate deposition. An arcarc collision in the Middle Jurassic also enhanced the siliciclastic deposition. Both phases of tectonic activity were linked with an increase in volcanics and volcaniclastics. Volcanism itself might have been an important control on sedimentation. A transition to carbonate-dominated sedimentation occurred in the Late Jurassic, reflecting a tectonically calm period

From cylindrical to non‐cylindrical foreland basin: Pliocene–Pleistocene evolution of the Po Plain–Northern Adriatic basin (Italy)

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