Lower Cretaceous unconformities related with tectonic events in the western Iberian margin

• Autores: Jorge L. Dinis, J. Rey
• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 3, 1, 2001 (Ejemplar dedicado a: XIV Congreso Nacional de Sedimentología, IV Congreso del Cretácico de España), págs. 141-144
• Idioma: español
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• Resumen

  • The Lower Cretaceous of the Lusitanian Basin (western Iberian margin) has a stratigraphical architecture that shows a slow and continuous postrift subsidence in the depocentric areas and subaerial exposure near the eastern margin. The main stratigraphic unconformities are interpreted as generated, essentially, by flexural isostasy and thermal adjustment to major extensional events in the adjacent rift segments, during the continental breakup. The late Berriasian unconformity matches the onset of oceanic crust (breakup) in the Tagus segment (southern) and the beginning of mantle exhumation or ultraslow seafloor spreading in the Iberian segment; the Barremian unconformity is considered as a response to the onset of seafloor spreading in the adjacent Iberian segment, coeval with a rifting episode in the Calician western margin, and the late Aptian unconformity corresponds to the breakup in the Galicia segment (northern). The three sedimentary cycles identified in the upper Aptian to upper Cenomanian can be correlated with main eustatic changes and pulses of intraplate transpressive stress created by the beginning of convergence of Iberia, during its counterclockwise movement, with Europe and Africa (or theAlboran microplate).