Cours ABG Marges passives

Ocean. Cr.10kmNon-volcanic passive margin structure : Gabon50kmpost-riftSyn-riftCont. Cr. thinnedMohoMohofrom Meyers et al. 199621Master1 BGAE Spécialité Géosciences Architecture des Bassins & Géomatique 2008 - Michel SéranneNNon-volcanic Passive margin structure : Gulf of LionECORSLowerCont.crustIntermediate crustLithosphere mantleLow angle faults, extreme crust thinning,antithetic lower crust/mantle detachment = Lower crust and/or mantle denudationfrom Séranne, 1999SCr.Oc.22Master1 BGAE Spécialité Géosciences Architecture des Bassins & Géomatique 2008 - Michel Sérannesyn-riftsedimentContinental rift-> passive margin : subsidencepost-rift sedimentSediment thicknessPreriftSynrifttimefast subsidence= synriftpostrift subsidence:cooling of the lithospherePreviously thinnedPostrift23Master1 BGAE Spécialité Géosciences Architecture des Bassins & Géomatique 2008 - Michel SéranneSubsidence of passive marginsCourbe théoriqueSubsidence due to geodynamicsTotal Subsidence = geodynamics + loadbackstripping from Gabon Margin24Master1 BGAE Spécialité Géosciences Architecture des Bassins & Géomatique 2008 - Michel Séranne6