Seismic and gravity constraints on the nature of the basement in the Africa-Eurasia plate boundary: New insights for the geodynamic evolution of the SW Iberian margin

• Published in: Journal of Geophysical Research: Solid Earth
• Main Authors: Martínez-Loriente, S., Sallarès, Valentí, Gràcia, Eulàlia, Bartolomé, Rafael, Dañobeitia, Juan José, Zitellini, Nevio
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Geophysical Union 2014
• Subjects: North Atlantic
• Online Access: http://hdl.handle.net/10261/108896; https://doi.org/10.1002/2013JB010476

23 pages, 10 pages, supporting information http://onlinelibrary.wiley.com/doi/10.1002/2013JB010476/suppinfo We present a new classification of geological domains at the Africa-Eurasia plate boundary off SW Iberia, together with a regional geodynamic reconstruction spanning from the Mesozoic extension to the Neogene-to-present- day convergence. It is based on seismic velocity and density models along a new transect running from the Horseshoe to the Seine abyssal plains, which is combined with previously available geophysical models from the region. The basement velocity structure at the Seine Abyssal Plain indicates the presence of a highly heterogeneous, thin oceanic crust with local high-velocity anomalies possibly representing zones related to the presence of ultramafic rocks. The integration of this model with previous ones reveals the presence of three oceanic domains offshore SW Iberia: (1) the Seine Abyssal Plain domain, generated during the first stages of slow seafloor spreading in the NE Central Atlantic (Early Jurassic); (2) the Gulf of Cadiz domain, made of oceanic crust generated in the Alpine-Tethys spreading system between Iberia and Africa, which was coeval with the formation of the Seine Abyssal Plain domain and lasted up to the North Atlantic continental breakup (Late Jurassic); and (3) the Gorringe Bank domain, made of exhumed mantle rocks, which formed during the first stages of North Atlantic opening. Our models suggest that the Seine Abyssal Plain and Gulf of Cadiz domains are separated by the Lineament South strike-slip fault, whereas the Gulf of Cadiz and Gorringe Bank domains appear to be limited by a deep thrust fault located at the center of the Horseshoe Abyssal Plain. ©2013. American Geophysical Union. All Rights Reserved The NEAREST project has been funded by the EU Programme “Integrating and Strengthening the European Research Area” of FP6, Sub-Priority 1.1.6.3, “Global Change and Ecosystems,” contract 037110, and the NEAREST-SEIS survey was funded by the Complementary Action ...