Crustal Structure of the Galicia Continental Margin (NW Spain) from Gravity Data Analysis and Modelling

Between 2001 and 2008, new marine gravity data have been collected over the North Atlantic Ocean rounding Galicia margin (NW Spain). We present a gravity data analysis and a N-S density model, focused on the interpretation of the crustal structure of the margin. For that purpose, a Complete Bouguer Anomaly grid has been calculated. This grid has been filtered in the frequency domain (both low-pass and band-pass filtering) to generate, respectively, a long-wavelength Bouguer Anomaly map (related to lithospheric mantle sources) and a mid-wavelength Bouguer Anomaly map (related to crustal density variations). Additionally, a N-S density model across this area has been performed. The analysis of these new data reveals the presence of compressive tectonics on this margin, particularly to the North, that generates crustal shortening and uplift of the seamounts area. During the Cenozoic compressive stage, besides the inversion of previous normal and strike-slip faults, new compressive structures are generated in the northern edge of the seamounts area, leading to the thickening of oceanic crust by means of a crustal-scale great fold and thrust, which is the westward continuation of those structures observed on the North Iberia compressive margin.