简介：Adeep,narrow,anddistortedBenioffzone,plungingfromtheIonianSeatowardsthesouthernTyrrhenianbasin,istheremnantofalongandeastwardmigratingsubductionofeasternMediterraneanlithosphere.FromOligocenetoRecent,subductiongeneratedtheWesternMediterraneanandtheTyrrhenianback-arcbasins,aswellasanaccretionarywedgeconstitutingtheSouthernAoenninicArc.IntheTyrrhenianSea,stretchingstartedinlateMioceneandeventuallyproducedtwosmalloceanicareas:theVavilovPlainduringPliocene(inthecentralsector)andtheMarsiliPlainduringQuaternary(inthesoutheasternsector).Theyareseparatedbyathickercrustalsector,calledtheIsselBridge.Back-arcexten-sionwasrapidanddiscontinuous,andaffectedalandlockedareawherecontinentalelementsofvarioussizesoccurred.DiscontinuitiesinextensionweremirroredbychangesinnatureofthelithospherescrapedofftoformtheSouthernApenninicArc.PartofthetectonicunitsofthesouthernApennines,accretedintothewedgefromlateMiocenetoPliocene,hadoriginallybeenlaiddownonthinnedconti-nentallithosphere,whichshouldconstitutethedeepportionofthepresentslab.AfterPlio-cene,onlyIonianoceaniclithospherewassubducted,becausethelargebuoyancyofthewideandnotthinnedcontinentallithosphereofApuliaandAfrica(Sicily)preservedtheseelementsfromrollbackofsubduction.AfterPliocene,thepassivelyretreatingoceanicslabhadtoadjustanddistortaccordingtothegeometryofthesecontinentalelements.ThelateonsetofarcvolcanisminrespecttothedurationofextensionintheTyrrhenian-Ioniansystemmayfindanexpla-nationconsideringaninitialstageofsubduc-tionofthinnedcontinentallithosphere.ThestrongPleistoceneverticalmovementsthatoccurredinthewholesoutheasternsystem(subsidenceintheback-arcbasinandupliftintheorogenicarc)mayinsteadberelatedtothedistortionoftheoceanicslab.