georefid:1996-049272SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=1996-0492721996-01-01publicationgeorefid:1996-049272Recq, M.Universite de Bretagne Occidentale, Departement des Sciences de la Terre, Brest, FranceauthorWhitmarsh, R. B.IFREMER, Plouzane, FranceauthorSibuet, J. C.authorWhite, R. S.authorLyness, D.authorGauthier-Villars, Montrouge, FrancepublisherdocumentHardcopyComptes Rendus de l'Academie des Sciences, Serie II. Sciences de la Terre et des Planetes322 (7)571-578Refraction profiles have been carried out along and across the peridotite ridge at the ocean-continent boundary west of the Galicia margin. Deep sea drilling (ODP Leg 103) shows that the ridge is composed of serpentinized peridotite. The shallow seismic velocity within the ridge is as low as 3.70 km/s, denoting a high grade of serpentinization. Modelling the ridge illustrates its heterogeneity and the large extent of the serpentinization from the crest to 6-8 km below sea floor. A unique downward velocity gradient within the ridge is ruled out. At a depth of 3 km below sea floor, the velocity gradient decreases abruptly through a second order discontinuity bisecting the ridge from west to east. Within a west-dipping transition zone at a depth of roughly 11 km, velocities increase from 7.40 to 7.65 km/s.completedApplied geophysicsAtlantic Oceanbathymetrycontinental crustcontinental margincrustdiscontinuitiesdredgingdrillingelastic wavesEuropeGalicia Spaingeophysical methodsgeophysical surveysIberian Peninsulaigneous rocksLeg 103Leg 105mantlemarine methodsmetasomatismmodelsNorth AtlanticNortheast AtlanticOcean Drilling Programocean floorsoceanic crustODP Site 647offshoreperidotitesplutonic rocksseismic methodsseismic wavesseismogramsserpentinizationSouthern EuropeSpainsurveyssynthetic seismogramsthermal circulationtransition zonesultramaficsupper mantlevelocity structureurn:org.iodp:exp:103urnlargerWorkCitationcampaignurn:org.iodp:exp:105urnlargerWorkCitationcampaignurn:org.iodp:exp:105:site:647urnlargerWorkCitationstudyurn:org.iodp:exp:105urnlargerWorkCitationcampaignFrenchgeoscientificInformation-80.000020.00000.000075.0000Galicia SpainNorth Atlantic