Results from the ESCI-N3.1 and ESCI-N3.2 marine deep seismic profiles in the northwestern Galicia Margin
- J. Álvarez-Marrón 1
- A. Pérez-Estaún 1
- J. J. Dañobeitia 1
- J. A. Pulgar 2
- J. R. Martínez Catalán 3
- A. Marcos 2
- F. Bastida 2
- J. Aller 2
- P. Ayarza Arribas 3
- J. Gallart 1
- F. González-Lodeiro 4
- E. Banda 1
- M. C. Comas 5
- D. Córdoba 6
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1
Instituto de Ciencias de la Tierra Jaume Almera
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2
Universidad de Oviedo
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3
Universidad de Salamanca
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4
Universidad de Granada
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5
Instituto Andaluz de Ciencias de la Tierra
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6
Universidad Complutense de Madrid
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ISSN: 0214-2708
Year of publication: 1995
Volume: 8
Issue: 4
Pages: 331-339
Type: Article
More publications in: Revista de la Sociedad Geológica de España
Abstract
The ESCI-N3 marine profile recorded 20 s of near vertical reflection seismic data offshore Northwest Galicia. This paper deals with two segments of the profile; ESCI-N3.1 which crosscuts the continental slope and a short part of the deep sea areas, and ESCI-N3.2 which images a section of the continental platform. In the ESCI-N3.1 profile, horizontal reflections from 6.5 to 8.8 s (TWT) correspond to an undisturbed package of sediments lying above an oceanic-type basement. A few kilometres long, strong horizontal reflection at 11.2 s may represent an oceanic Moho reflection. A tectonic accretionary prism is seen at the ocean-continent transition, and a band of reflections dips gently towards the south-east, from the base of the gently dipping continental slope. The ESCI-N3.2 profile, is characterised by bright, continuous lower crustal reflections from 8 to 10 s. A band of strong sub-Moho reflections dips gently towards the south-west from 10 to 13.5 s. The reflective features imaged in these profiles are correlated with major structures that evidence the various tectonic events comprising the geological history of the area. This history includes at least three main tectonic events, the Variscan collision during Palaeozoic times, a subsequent rifting with formation of the Bay of Biscay basin during the Mesozoic, and a compressional event in the Cenozoic.