Cours ABG Marges passives

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Structure of non-volcanic vs volcanic marginsOcean. cr. C.O.B.Stretched Cont. cr.Ocean. cr.igneous crust.Cont. cr.13Master1 BGAE Spécialité Géosciences Architecture des Bassins & Géomatique 2008 - Michel SéranneFormation of volcanic marginsMantle fusion (lithosph + asthenosph)Upwelling of asthenosphereLarge lava flows (traps)Dike intrusion in Cont. Cr.Emplacement of grabbro bodies atMoho = underplatingBreak-up : accretion of oceanic crustAfter break-up : differential subsidence=> Seaward dipping lava flowActive rifting => volcanic marginsubsidence14Master1 BGAE Spécialité Géosciences Architecture des Bassins & Géomatique 2008 - Michel Séranne©NOAAParanaBasalticTrapsVolcanic vs non-volcanic marginsmid-Atlantic ridgeTristan da CunhaHot-spotWalvis RidgeAngolaNamibie15Master1 BGAE Spécialité Géosciences Architecture des Bassins & Géomatique 2008 - Michel SéranneLIP’s: basalt plateaus = trapsAssociated with volcanic margins(e.g. Atlantic volcanic M.)Large Igneous ProvincesPlume = convection => decompression => mantle fusion16Master1 BGAE Spécialité Géosciences Architecture des Bassins & Géomatique 2008 - Michel Séranne4
Non-volcanic margin : Stretched lithosphereWest iberian marginRestonManatschal & al , 200117Master1 BGAE Spécialité Géosciences Architecture des Bassins & Géomatique 2008 - Michel SéranneStretched lithosphere & mantle denudationNon-volcanicMarginsEx: Tethysian marginFroitzheim & al18Master1 BGAE Spécialité Géosciences Architecture des Bassins & Géomatique 2008 - Michel SéranneUpper plate(Newfoundland)Continent-Ocean BoundaryPERON-PINVIDIC, Gwenn (2006)lower plate(Iberia)•Conjugate margins•Oc.crust accretion•Drifting•Break-up: 1st accretion•Formation of 1st magneticanomalies,• Mantle exhumation &serpentinisation• End of rifting (no morefaulting)19Master1 BGAE Spécialité Géosciences Architecture des Bassins & Géomatique 2008 - Michel SérannerésistanceprofondeurBreak-up = end of riftinglithosphere structure => depth of necking => isostatic flexural responseBreak-up unconformity : signature of stress release20Master1 BGAE Spécialité Géosciences Architecture des Bassins & Géomatique 2008 - Michel Séranne5
Page 2 and 3: Déformation cassanteDéformation d
Page 6 and 7: Ocean. Cr.10kmNon-volcanic passive
Page 8 and 9: waterdepth:3500mSalt tectonics : sh

Cours ABG Marges passives

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