Pre-Mesozoic Basement of the Western Iberian Continental Margin and Its Place in the Variscan Belt

Capdevila, R.; Mougenot, D.

doi:10.2973/odp.proc.sr.103.116.1988

Cited by 33 publications

(38 citation statements)

References 22 publications

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“…Extensive Carboniferous-Permian clastic deposits have been documented on the Laurussian continent, in particular on the Grenville, Avalonia and Meguma terranes (e.g., Lowe et al, 2011;Piper et al, 2012;Morton et al, 2015) and several remnants have been found on the NW Iberia margin (e.g., Capdevila and Mougenot, 1988). Previous authors have proposed that these continental deposits were much more extensive at the time of Pangea break-up than today (Corrales, 1971;Piper et al, 2012;Dinis et al, 2016).…”

Section: Late Carboniferous-permian (Late Amalgamation)mentioning

confidence: 99%

The transition from Pangea amalgamation to fragmentation: Constraints from detrital zircon geochronology on West Iberia paleogeography and sediment sources

Dinis

Fernandes

Jorge

et al. 2018

Sedimentary Geology

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Detrital zircon U-Pb geochronology data from late Carboniferous to Triassic clastic sedimentary rocks in SW Iberia were used to investigate the regional paleogeography during the transition from Pangea amalgamation to breakup. The major U-Pb zircon age peaks are middle Devonian to Carboniferous (~390-300 Ma), CambrianOrdovician (~530-440 Ma), Cryogenian-Ediacaran (~750-540 Ma), Stenian-Tonian (~1.2-0.9 Ga) and Paleoproterozoic (~2.3-1.8 Ga). Rapid exhumation of Variscan crystalline rocks at the contact between the South Portuguese zone and Ossa Morena Zone, explains the abundance of late Paleozoic ages in the upper Carboniferous-lower Permian continental successions. The U-Pb zircon data constrain the maximum depositional age of the Santa Susana Basin to c. 304 Ma and the Viar Basin to c. 297 Ma. The Triassic sequences, despite being c. 100 Ma younger than the Variscan tectonothermal events, contain low proportions of late Paleozoic zircon. The major peaks in all zircon spectra closely resemble those found in the adjacent basement rocks, indicating small source areas, mainly located near the rift shoulders. Longer travelled fluvial systems are postulated for the eastern portions of the Algarve Basin, which was closer to the westward advancing Tethys Ocean than the rift basins of West Iberia. Sequences that contain significant proportions of~1.2-0.9 Ga zircon are probably recycled from post-collisional Carboniferous-Permian continental deposits that were more extensive than those found today.

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Section: Late Carboniferous-permian (Late Amalgamation)mentioning

confidence: 99%

The transition from Pangea amalgamation to fragmentation: Constraints from detrital zircon geochronology on West Iberia paleogeography and sediment sources

Dinis

Fernandes

Jorge

et al. 2018

Sedimentary Geology

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“…Region D contains the southern flank of Galicia Bank and seismic observations (see below), dredging and drilling strongly suggest that it consists of thinned continental crust (Capdevila & Mougenot 1988;ODP Leg 173 Shipboard Scientific Party 1998;Chian et al 1999).…”

Section: Introductionmentioning

confidence: 97%

The role of syn-rift magmatism in the rift-to-drift evolution of the West Iberia continental margin: geophysical observations

Whitmarsh

Minshull

Russell

et al. 2001

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The presence of a well-defined ocean-continent transition (OCT) and the absence of large volumes of extrusive or intrusive rocks on the West Iberia margin make it a good place to investigate how the largely amagmatic rifting and break-up of continental lithosphere evolves into oceanic crust produced by magmatic sea-floor spreading. In the southern Iberia Abyssal Plain there is a broad OCT with a characteristic seismic and magnetic character, distinct from both thinned continental crust and normal oceanic crust, which supports the notion that it consists predominantly of exhumed and serpentinized mantle. Interpretations of magnetic and seismic data indicate that on average only small amounts of syn-rift melt exist within the OCT. Isolated, probably margin-parallel, intrusive melt bodies are scattered within the eastem part of the OCT well beneath the top of acoustic basement. Within the western part of the OCT, closer to unambiguous sea-floor spreading magnetic anomalies, such bodies were later(?) emplaced at higher levels and more closely together in the basement until eventually sea-floor spreading began. The evidence does not support the hypothesis that ultraslow sea-floor spreading can explain the magnetic anomalies observed within the wider parts of the West lberia OCT, where the OCT evolution is best resolved.

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“…5). Cette suture ~'Ctendrait depuis les Appalaches du sud jusqu'h la Zone d'Ossa-Morena dans la ptninsule ibCrique (Capdevila et Mougenot 1988).…”

Section: Schcma Palcogcographique Au Dcvonien Infirieur (Fig 4)unclassified

Évolution paléogéographique de la marge nord-ouest de l'Afrique du Cambrien à la fin du Carbonifère (du Maroc au Libéria)

Villeneuve¹,

Cornée²

1991

Can. J. Earth Sci.

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R e p le 12 juin 1990 RCvision acceptCe le 15 mars 199 1Des schCmas palCogCographiques sont proposts au PalCozoi'que pour la marge nord-ouest du craton ouest-africain. Au Cambrien prCcoce, il y a un rCgime distensif et une transgression marine. Au Cambrien moyen, l'oroge?&se des RokClides chasse la mer au sud tandis que l'ouverture du proto-Atlantique se poursuit au nord de la dorsale Reguibat. A l'ordovicien prCcoce et moyen se place une immense plate-forme marine stable. A l'ordovicien tardif a lieu une rkgression gCnCralisCe avec la formation de l'inlandsis ouest-africain. Au Silurien, cette mer transgresse trks largement sur la plate-forme afric+ne. Au DCvonien prkcoce, les prCmices des dCformations hercyniennes se manifestent au Maroc par des horst et des grabens. A la fin du DCvonien et au debut du Carbonifere, la mer ne subsiste que dans quelques bassins ou sillons tectoniques isolCs. Au Carbonifere tardif, la collision entre 1'Afrique de l'ouest et 1'AmCrique du Nord transforme cette marge du PalCozoi'que infkrieur en une zone orogCnique hercynienne dont la structuration apparait dependante du dCcoupage en blocs crustaux apparu d&s le Cambrien, probablement greffC sur d'anciennes zones de faiblesse panafricaines.Paleogeographic reconstructions of Paleozoic time are presented for the northwest margin of the West-African Craton. An extensional regime and a marine transgression were dominant during the Early Cambrian. During the Middle Cambrian, the RokClides orogen was responsible for the sea regression to the south, while the proto-Atlantic opening was active to the north of the Reguibat shield. A large stable marine platform was present during Early and Middle Ordovician. A general regression and the formation of the West-African Inlandsis took place during the Late Ordovician. During Silurian time, this sea transgressed over most of the African platform. Incipient Hercynian deformations during the Early Devonian produced horsts and grabens in Morocco. At the end of the Devonian and the beginning of the Carboniferous, the sea was restricted to isolated basins and tectonic trenches. Collision between West Africa and North America during the Late Carboniferous transformed the Lower Paleozoic margin into an Hercynian orogenic belt, whose structure is controlled by the presence of crustal blocks, generated as early as the Cambrian, and probably reflecting, in turn, older Panafrican zones of weakness.[Translated by the Journal]Can.

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Pre-Mesozoic Basement of the Western Iberian Continental Margin and Its Place in the Variscan Belt

Abstract: The study of plutonic and metamorphic rock samples from 15 dredge hauls and 41 cores

Cited by 33 publications

References 22 publications

The transition from Pangea amalgamation to fragmentation: Constraints from detrital zircon geochronology on West Iberia paleogeography and sediment sources

The transition from Pangea amalgamation to fragmentation: Constraints from detrital zircon geochronology on West Iberia paleogeography and sediment sources

The role of syn-rift magmatism in the rift-to-drift evolution of the West Iberia continental margin: geophysical observations

Évolution paléogéographique de la marge nord-ouest de l'Afrique du Cambrien à la fin du Carbonifère (du Maroc au Libéria)

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