Tectonic wedge escape in the southwestern front of the Rif Cordillera (Morocco)

18 páginas, 12 figuras.-- Editores: G. Moratti y A. Chalouan.The Rif Cordillera is a part of the Alpine orogenic arc in the Western Mediterranean, which was developed by the interaction of the westward motion of the Alboran Domain between the converging Eurasian and African plates. The Prerif Ridges, located along the southwestern front of the Rif, are south-vergent folds that are in places associated with faults affecting Jurassic to Quaternary sedimentary rocks and slope breccias that evidence the deformations that were active over the Neogene-Quaternary period. The different southward or southwestward displacement of each Prerif Ridge is related to the development of frontal and lateral ramps, which may or may not reach the surface. Oblique shortening may be explained by southwestward escape of large tectonic wedges, bounded by large strike-slip faults: the North-Middle Atlas fault which extends northward into the Alboran Sea, the Fez-Tissa-Taïneste fault, the Bou Draa-Sidi Fili fault, the Jebha fault and the Fahies fault. The relative displacement of these tectonic wedges toward the SW may explain the NNE-SSW to ENE-WSW compression observed in the Rif front and in the northern part of its Meseta-Atlas foreland.The research has been financed by collaborative Spanish-Moroccan projects of the Junta de Andalucfa, the AECI and CICYT project BTE2003-01699.Peer reviewe

Propagación de las deformaciones plio-cuaternarias del frente del Rif hacia el antepaís

4 páginas.-- Trabajo presentado en el VI Congreso Geólógico de España, Zaragoza, 12-15 julio, 2004.Peer reviewe

Carbon nanotubes

International audienceCarbon nanotubes (CNT s) are remarkable objects that once looked set to revolutionize the technological landscape in the near future. Since the 1990s and for twenty years thereafter, it was repeatedly claimed that tomorrow's society would be shaped by nanotube applications, just as silicon-based technologies dominate society today. Space elevators tethered by the strongest of cables, hydrogen-powered vehicles, artificial muscles: these were just a few of the technological marvels that we were told would be made possible by the science of carbon nanotubes. Of course, this prediction is still some way from becoming reality; most often the possibilities and potential have been evaluated, but actual technological development is facing the unforgiving rule that drives the transfer of a new material or a new device to market: profitability. New materials, even more so for nanomaterials, no matter how wonderful they are, have to be cheap to produce, constant in quality, easy to handle, and nontoxic. Those are the conditions for an industry to accept a change in its production lines to make them nanocompatible. Consider the example of fullerenes – molecules closely related to nanotubes. The anticipation that surrounded these molecules, first reported in 1985, resulted in the bestowment of a Nobel Prize for their discovery in 1996. However, two decades later, very few fullerene applications have reached the market, suggesting that similarly enthusiastic predictions about nanotubes should be approached with caution, and so should it be with graphene, another member of the carbon nanoform family which joined the game in 2004, again acknowledged by a Nobel Prize in 2010. There is no denying, however, that the expectations surrounding carbon nanotubes are still high, because of specificities that make them special compared to fullerenes and graphene: their easiness of production, their dual molecule/nano-object nature, their unique aspect ratio, their robustness, the ability of their electronic structure to be given a gap, and their wide typology etc. Therefore, carbon nanotubes may provide the building blocks for further technological progress, enhancing our standard of living. In this chapter, we first describe the structures, syntheses, growth mechanisms, and properties of carbon nanotubes. Then we introduce nanotube-based materials, which comprise on the one hand those formed by reactions and associations of all-carbon nanotubes with foreign atoms, molecules and compounds, and on the other hand, composites, obtained by incorporating carbon nanotubes in various matrices. Finally, we will provide a list of applications currently on the market, while skipping the potentially endless and speculative list of possible applications