Manioc : Portail | resultats 21 - 40 pour la recherche: H. Deschamps,

Mémoire pour le chef de brigade Magloire Pélage et pour les habitants de la Guadeloupe chargés par cette colonie de l'administration provisoire après le départ du capitaine général dans le mois de brumaire an X T.2
Auteur(s) : Frasans, Hippolyte de (1768-18..) Langloys, Jean-Thomas (1746-1804)
Année de publication :

| Plus

Histoire de la littérature haïtienne ou L' âme noire
Auteur(s) : Vaval, Duraciné (1879-1952)
Année de publication :

| Plus

Bulletin officiel de la Guyane française
Année de publication :

| Plus

Traité sur les terres noyées de la Guiane, appelées communément Terres-Basses, sur leur dessèchement, leur défrichement, leur culture et l'exploitation de leurs productions...
Auteur(s) : Guisan, Jean Samuel (1740-1801)
Année de publication :

| Plus

En Haïti : planteurs d'autrefois, nègres d'aujourd'hui
Auteur(s) : Aubin, Eugène (1863-1931)
Année de publication :

| Plus

Mémoire pour le chef de Brigade Magloire Pélage et pour les habitants de la Guadeloupe. Tome second
Auteur(s) : Frasans, Hippolyte de (1768-18..) Langloys, Jean-Thomas (1746-1804)
Année de publication :

| Plus

Catalogue des produits des colonies françaises envoyés à l'exposition universelle de Londres de 1862
Année de publication :

| Plus

L'illustration. N°3358
Auteur(s) : Galmot, Jean (1879-1928)
Année de publication :

| Plus

Upper mantle flow beneath and around the Hangay Dome, central Mongolia
Auteur(s) : Barruol, Guilhem Deschamps, Anne Déverchère, Jacques Mordvinova, Valentina V. Munkhuu, Ulziibat Perrot, Julie Artemiev, A. Dugarmaa, T.
Auteurs secondaires : Géosciences Montpellier ; Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) Géoazur (GEOAZUR) ; Université Pierre et Marie Curie - Paris 6 (UPMC) - Université Nice Sophia Antipolis (UNS) ; Université Côte d'Azur (UCA) - Université Côte d'Azur (UCA) - Institut national des sciences de l'Univers (INSU - CNRS) - Observatoire de la Côte d'Azur - Centre National de la Recherche Scientifique (CNRS) Université européenne de Bretagne (UEB) Domaines Océaniques (LDO) ; Centre National de la Recherche Scientifique (CNRS) - Institut d'écologie et environnement - Observatoire des Sciences de l'Univers - Université de Brest (UBO) - Institut national des sciences de l'Univers (INSU - CNRS) Institute of the Earth's crust ; Siberian Branch of the Russian Academy of Sciences (SB RAS) Research Center of Astronomy and Geophysics of the Mongolian Academy of Science

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Mongolia represents the northernmost area affected by the India–Asia collision, and it is actively deformed along transpressive belts closely associated with large-scale strike-slip faults. The active and past mantle flow beneath this region is, however, poorly known. In order to investigate deep mantle deformation beneath central Mongolia and its relation with the surrounding major structures such as the Siberian craton, the Gobi–Altay belt and the Baikal rift, a NS-trending profile of broadband seismic stations has been deployed in the summer 2003 from the southern Siberian craton to the Gobi–Altay range, crossing the entire Hangay dome. Mantle flow is deduced from the splitting of teleseismic shear waves such as SKS phases. In eastern Mongolia, the permanent station ULN in Ulaanbaatar reveals the presence of two anisotropic layers, the upper one being oriented NE–SW, close to the trend of lithospheric structures and the lower one NW–SE, close to the trend of Eurasia absolute plate motion. Along the NS profile in central Mongolia, seismic anisotropy deduced from SKS splitting reveals a homogeneous NW–SE trending structure, fully consistent with the observations made in the Altay–Sayan in western Mongolia. The observed delay times of 1.5 to more than 2.0 s favor consistent mantle flow over large mantle thicknesses. Since the lithosphere is less than 100 km thick beneath central Mongolia and since the observed fast directions are parallel to the trend of the lithospheric structures but also close to the trend of the absolute plate motion, we propose that both the lithosphere and the asthenosphere may join their anisotropic effects beneath central Mongolia to explain the large delay times. Although GPS vectors represent the instantaneous displacement of the Earth's surface and SKS splitting the time and vertical integration of finite strain at depth, we use the opportunity of the dense geodetic measurements available in this region to discuss the anisotropy pattern in term of present-day deformation. In the Eurasia-fixed reference frame, GPS and SKS both depict a similar trend beneath central Mongolia, suggesting a lithospheric block “escaping” toward the east that could orient olivine a-axes in the upper mantle, within a transpressive tectonic regime. A different behaviour is observed in western Mongolia: the GPS vectors trend NS, close to the regional compression direction, whereas the fast SKS directions trend EW, suggesting a tectonic regime close to a mode of axial shortening, generating the development of an EW-trending foliation at depth. We therefore propose that Mongolia is a place where active and frozen lithospheric deformation may add their effects, together with the sublithospheric flow. In the three sources of anisotropy inferred, a fundamental role is played by the Siberian craton that acted as an undeformable core of the continent through time: the frozen Paleozoic and Mesozoic structures wrap around the craton, building up the fast anisotropic direction pattern; the present-day sublithospheric flow induced by the plate motion is likely deflecting around its deep roots; finally, the present-day tectonic regime appears to be controlled by the presence of the craton to the north.
ISSN: 0012-821X

hal-00407853
https://hal.archives-ouvertes.fr/hal-00407853
https://hal.archives-ouvertes.fr/hal-00407853/document
https://hal.archives-ouvertes.fr/hal-00407853/file/Barruol_SKS_Mongolia_EPSL2008_hal.pdf
DOI : 10.1016/j.epsl.2008.07.027

| Plus