The ocean-continent transition of western Iberia
- Inst. of Oceanographic Sciences Deacon Lab., Surrey (United Kingdom)
- Univ. Pierre et Marie Curie, Villefranchesur-Mer (France)
- Univ. de Bretagne Occidentale, Brest (France)
The western continental margin of the Iberian peninsular has the characteristic of a rifted non-volcanic continental margin with half-graben and tilted fault blocks seen in several places on multichannel seismic reflection profiles. The ocean-continent transition (OCT) is therefore expected to be where thinned continental crust and oceanic crust are juxtaposed, as elsewhere. The authors located the OCT off western Iberia in order to constrain the pre-lift fit of Iberia to North America. This fit is only marginally constrained by sea-floor spreading magnetic anomalies because the Cretaceous constant polarity interval is adjacent to the OCT. Thinned continental crust can be distinguished from oceanic crust by the nature of the lower crustal velocity structure. In 1986-1987, a series of seismic refraction profiles was shot across three parts of the Iberian Abyssal Plain, the OCT can be detected not only from seismic velocities but also by modeling magnetic anomalies. The chosen location of the OCT is consistent with the interpretation of subsequently acquired multichannel profiles. Off Galicia Bank, the OCT, recognized from seismic velocities and multichannel profiles, corresponds to a seabed peridotite ridge, which has been extensively sampled. In the Tagus Abyssal Plain, limited seismic data gives a less clear picture of the OCT.
- OSTI ID:
- 5814807
- Report Number(s):
- CONF-910978-; CODEN: GEOBE
- Journal Information:
- Geobyte; (United States), Vol. 75:8; Conference: International conference and exhibition of the American Association of Petroleum Geologists (AAPG): the way ahead-hydrocarbons for the 1990s, London (United Kingdom), 29 Sep - 3 Oct 1991; ISSN 0885-6362
- Country of Publication:
- United States
- Language:
- English
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