10 research outputs found
Un exemple de coopération technique
Présentation Daniel Georgen, ingénieur-chimiste. Ma carrière s’est partagée entre la France et le Brésil où j’ai travaillé neuf ans et demi. En tant que représentant du secteur des entreprises, je voudrais porter témoignage ici de l’expérience vécue dans le domaine de la coopération industrielle par le groupe multinational Rhône-Poulenc et sa filiale brésilienne Rhodia S.A., fondée en 1919 ! La coopération industrielle La coopération est en effet aussi l’expression de l’intérêt manifesté de p..
Um exemplo de cooperação técnica
apresentação Daniel Georgen, engenheiro químico. Minha carreira dividida entre a França e o Brasil, onde trabalhei por nove anos e meio. Na qualidade de representante do setor das empresas, gostaria de testemunhar, aqui, a experiência vivida no campo da cooperação industrial pelo grupo multinacional Rhône-Poulenc e sua filial brasileira Rhodia S.A., fundada em 1919! a cooperação industrial A cooperação industrial é, com efeito, também a expressão do interesse manifestado por ambas as partes, ..
Propagation of a melting anomaly along the ultraslow Southwest Indian Ridge between 46°E and 52°20′E: interaction with the Crozet hotspot?
Magmatic breakup as an explanation for magnetic anomalies at magma-poor rifted margins
International audienc
Spreading rate, spreading obliquity, and melt supply at the ultraslow spreading Southwest Indian Ridge
We use bathymetry, gravimetry, and basalt composition to examine the relationship between spreading rate, spreading obliquity, and the melt supply at the ultraslow spreading Southwest Indian Ridge (SWIR). We find that at regional scales (more than 200 km), melt supply reflects variations in mantle melting that are primarily controlled by large-scale heterogeneities in mantle temperature and/or composition. Focusing on adjacent SWIR regions with contrasted obliquity, we find that the effect of obliquity on melt production is significant (about 1.5 km less melt produced for a decrease of 7 mm/a to 4 mm/a in effective spreading rates, ESR) but not enough to produce near-amagmatic spreading in the most oblique regions of the ridge, unless associated with an anomalously cold and/or depleted mantle source. Our observations lead us to support models in which mantle upwelling beneath slow and ultraslow ridges is somewhat focused and accelerated, thereby reducing the effect of spreading rate and obliquity on upper mantle cooling and melt supply. To explain why very oblique SWIR regions nonetheless have large outcrops of mantle-derived ultramafic rocks and, in many cases, no evidence for axial volcanism [Cannat et al., 2006; Dick et al., 2003], we develop a model which combines melt migration along axis to more volcanically robust areas, melt trapping in the lithospheric mantle, and melt transport in dikes that may only form where enough melt has gathered to build sufficient overpressure. These dikes would open perpendicularly to the direction of the least compressive stress and favor the formation of orthogonal ridge sections. The resulting segmentation pattern, with prominent orthogonal volcanic centers and long intervening avolcanic or nearly avolcanic ridge sections, is not specific to oblique ridge regions. It is also observed along the SWIR and the arctic Gakkel Ridge in orthogonal regions underlain by cold and/or depleted mantle