Reassessment of the Galicia interior basin structure, West Iberia margin, from new seismic images

VI Simposio Internacional de Ciencias del Mar - VI International Symposium of Marine Sciences (ISMS 2018), 20- 22 June 2018, Vigo.-- 2 pagesThe Galicia Interior Basin (GIB) is a ~3 km deep bathymetric trough located at the non-volcanic margin off West Iberia. It is considered as an aborted rift in the context of the opening of the North Atlantic rift system, one of the best studied non-volcanic margins. However, most of the works have focused on the Deep Galicia Margin and Iberian Abyssal Plain segments, and the role of the GIB in the regional geodynamic framework remains poorly understood. In this sense, GIB represents the necessary link to understand the mechanisms of extension from the little extended shelf to the areas where continental breakup finally occurs. We present a series of reprocessed vintage multichannel seismic profiles collected across the GIB. Using state-of-the-art techniques, we have improved the entire crustal structure and the resulting image is far superior to original processing. We applied Tau-P and Wiener predictive deconvolution and multiple attenuation by both radon filtering and wave-equation-based surface-related multiple elimination (SRME) to increase the signal to noise ratio. Post-stack time migration improved the image of the complex basement structure and deep sedimentary units, which was unclear in previous publications. The reprocessed seismic lines run perpendicular to the margin’s trend from the continental shelf across the GIB to the Galicia Bank, providing the opportunity to study the 3D tectonic structure of the GIB. The resulting high-quality images show syn - and post -rift sediment, tilted fault blocks, clear top-of-the-basement reflections, and also intra-basement and Moho reflections that offer new information about the tectonic structural style during rifting. The data display variation in the amount and distribution of crustal extension along the basin that permits to speculate on the reasons for the rift failure at the GIB in the context of the opening of the West Iberia marginALC acknowledges the Xunta de Galicia for a postdoctoral contract funded by the ‘Programa de axudas á etapa posdoutoral da Xunta de Galicia’ (Consellería de Cultura, Educación e Ordenación Universitaria). This work was carried out jointly within the ‘Grup de Recerca Consolidat de la Generalitat de Catalunya’ B-CSI (2014SGR940) and the Geología Marina y Ambiental (Geoma-XM2) GroupPeer Reviewe