Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Spinel (± plagioclase) peridotite xenoliths from the Tallante and Los Perez volcanic centres in the eastern Betics (SE Spain) range from depleted (clinopyroxene-poor) harzburgites to fertile (clinopyroxene-rich) lherzolites and orthopyroxene-free wehrlites. Significantly, only one harzburgite, which is depleted in heavy rare earth elements (HREE), retains the imprint of ca. 20% ancient melting of an original garnet lherzolite source. In contrast, REE abundances of other harzburgites and lherzolites from the eastern Betics have been increased by melt-rock reaction. The whole-rock and mineral compositions of these mantle rocks are largely controlled by three types of modal metasomatism: 1) common clinopyroxene-orthopyroxene addition and olivine consumption which increased FeOt, SiO2 and Al2O3, and decreased MgO compared to the refractory melting products; 2) subordinate orthopyroxene dissolution and precipitation of clinopyroxene and olivine, which led to higher FeOt and MgO and lower SiO2 than in common (orthopyroxene-rich) lherzolites; and 3) rare orthopyroxene consumption and olivine addition that caused higher FeOt and lower SiO2 compared to the original melting residues. These mineral modal and major element variations have been produced mostly by interactions with relatively FeOt-rich/SiO2-poor melts, likely derived from a peridotite-pyroxenite lithospheric mantle with a highly heterogeneous isotopic composition. Melting of the lithospheric mantle in the western Mediterranean was triggered by upwelling of the asthenosphere induced by back-arc extension in the Late Oligocene-Early Miocene. Trapping of small fractions of exotic melts in whole-rocks — likely the parental magmas of Miocene back-arc dykes that intruded the Betic crust — caused local disequilibrium between the trace element signatures and Pb isotopic compositions of clinopyroxene and whole-rock. Subsequent interaction with SiO2-undersaturated magmas, similar to the parental melts of the Pliocene alkali basalts that host the xenoliths, promoted orthopyroxene consumption and clinopyroxene-olivine enrichment at locations close to magma conduits, and finally generated orthopyroxene-free wehrlites. This event constitutes the last episode of the Cenozoic magmatic evolution of the westernmost Mediterranean which is recorded in the mantle xenoliths from the eastern Betics.
ISSN: 0024-4937

hal-01553092
https://hal.archives-ouvertes.fr/hal-01553092
DOI : 10.1016/j.lithos.2016.12.011

Éditeur(s) : HAL CCSD
Résumé : International audience
Until the end of the 20th century, heritage was mainly defined in the Caribbean, as in the entire world, by an european conception (linked with the formation of national identities), founded on the value of tangible heritage (rare, ancient objects, monuments and materials) as an historic proof of the value of cultures and peoples. Poets in the Caribbean hardly criticize this evidence that contributed to inferiorized people. Memory and imagination played a central role in the building of a Caribbean cultural identity. Poets tried to show how the common could rise from different patterns, diversity instead of unity, creation instead of fixity. Nevertheless, In the 21st century, frameworks are not available to deal with Caribbean heritage in its diversity (monuments, material, natural and intangible...) and complexity whereas it constitute a challenge for a sustainable society and can play a fundamental role in education as in tourism.
Jusqu'à la fin du XXe siècle, le patrimoine dans la Caraïbe comme ailleurs dans le monde, répondait principalement à une conception européenne (liée à la formation des identités nationales) fondée sur la valeur positive du patrimoine matériel comme preuve historique de la valeur des cultures et des peuples. Les poètes caribéens ont déconstruit ce cadre, instrument de l'infériorisation des individus. La mémoire et l'imagination ont joué un rôle central dans la construction d'une identité culturelle caribéenne. Ils ont tenté de montrer que le commun pouvait émerger de modèles différents, opposant à l'unique, le divers et à la fixité, la création. Cependant, au XXIe siècle, la Caraïbe ne dispose pas d'un cadre pour traiter son patrimoine dans sa diversité (patrimoine matériel, immatériel, naturel) et sa complexité alors que le patrimoine constitue un défi pour le développement durable des sociétés et peut jouer un rôle fondamental dans l'éducation et le tourisme.
Caribbean Studies Association annual conference
Port-au-Prince, Haiti

hal-01612909
https://hal.univ-antilles.fr/hal-01612909