Evolution of deep-margin extensional basins: The continental slope basins offshore West Iberia

Alves, Tiago ORCID: https://orcid.org/0000-0002-2765-3760, Moita, Carlos, Pinheiro, Luis and Monteiro, Jose 2003. Evolution of deep-margin extensional basins: The continental slope basins offshore West Iberia. Presented at: AAPG International Conference, Barcelona, Spain, 21-24 September 2003.

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Abstract

A new set of multi-channel (2D) seismic reflection data, acquired by TGS-NOPEC in 2000 and 2001, has been used to characterise the tectono-sedimentary evolution of the continental slope basins offshore west Iberia. The new data were compared with seismic and well information on the Porto and Northern Lusitanian Basins. The deep margin north of the Nazaré fault is intersected by northwest- to northeast-trending normal faults that bound distinct Mesozoic half-graben/graben sub-basins. East-northeast faults separate sectors with distinct tectono-sedimentary evolutions. On the interpreted profiles, the thickness of the Cretaceous rift-related units is relatively minor and wedge-shaped syn-/post-rift packages are limited to two sub-basins. In contrast, the more than 1000 ms two-way travel-time (TWTT) of Late Cretaceous-Cenozoic sediments mark an important period of post-rift subsidence accompanied by substantial sediment supply from hinterland areas. The models for the formation of passive continental margins suggest that crustal heterogeneities, basement Hercynian structures and the relative position of the zone of ductile stretching underneath the upper crust controlled the subsidence history and physiography of the offshore basins during the Mesozoic rifting. This complex setting was further disturbed by the Alpine tectonism, which increased the basin compartmentalisation, rejuvenated hinterland and intra-basin sediment-source areas, caused local deepening on the margin and triggered halokinesis.

Item Type:	Conference or Workshop Item - unpublished
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Earth and Environmental Sciences
Last Modified:	30 Oct 2026 13:50
URI:	https://orca.cardiff.ac.uk/id/eprint/73782

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