Margin segmentation prior to continental break-up: A seismic–stratigraphic record of multiphased rifting in the North Atlantic (Southwest Iberia)

A crustal‐scale view at rift localization along the fossil Adriatic margin of the Alpine Tethys preserved in NW Italy

“…Rifted continental margins commonly record multiple stages of diffuse crustal stretching [e.g., Direen et al ., ; Faleide et al ., ; Ball et al ., ]. Within this context, renewed stretching is not necessarily localized along domains that accommodated greater extension during the previous rifting stages [e.g., Cowie et al ., ; Faleide et al ., ; Pereira and Alves , ]. As a result, rift systems are generally observed to shift in time and space within evolving margins, ahead of strain localization leading to lithospheric breakup.…”

Mesozoic and Cenozoic exhumation history of the SW Iberian Variscides inferred from low-temperature thermochronology

“…Thus, rift shoulder erosion would have yielded the large volume of clastic sediments deposited in the Lusitanian basin at Late Jurassic times (Kullberg, 2000;Rasmussen et al, 1998). Furthermore, the variation of cooling ages in small distances (see also Stapel, 1999) suggests that areas experiencing exhumation were relatively small and changed through time, which, in turn, is in agreement with the migration of the locus of extension in the Alentejo margin along the Mesozoic (Pereira and Alves, 2011).…”

“…The thermal input from this mantle plume and the associated intrusions would have produced general exhumation in SW Iberia, which, in turn, would be responsible for the Late Cretaceous cooling event recorded by the AFT ages. Actually, a seismic survey in the Alentejo margin shows that Upper Cretaceous sediments are tilted and eroded due to surface uplift coeval with the intrusion of the alkaline massifs (Pereira and Alves, 2011).…”

Site U1391

“…The plastered drift at this site is one of a series of contourite features formed under the influence of the northern branch of MOW as it continues north along the Iberian margin and beyond (Iorga and Lozier, 1999;Serra et al, 2010). These in-clude those along the middle slope of the northwest Portuguese margin (Alves et al, 2003;Pereira and Alves, 2011), the Galicia Bank and Galician slope (Ercilla et al 2009(Ercilla et al , 2010(Ercilla et al , 2011Bender et al 2010;Mena et al 2010), Ortegal Spur (Hernández-Molina et al 2009), Le Danois Bank or "Cachucho" (Ercilla et al 2008;Iglesias, 2009;Van Rooij et al 2010), and the Porcupine slope (Van Rooij et al, 2003).…”

“…These previous studies identified that the sedimentary record of the southwest Portuguese margin spans from the Late Triassic through Quaternary and consists of Mesozoic rift and postrift sediments deformed during the Cenozoic alpine compression (Terrinha et al, 2003). Major unconformities/hiatuses generated during this tectonic inversion phase separate Late Cretaceous from middle Eocene sediments and late Eocene from early Miocene sediments (Alves et al, 2003;Pereira et al, 2011). The present-day morphostructural attributes of the margin are the result of the middle Miocene uplift of fault blocks inherited from the Mesozoic rifting phases.…”