Structure of the European Continental Margin Between Portugal and Ireland, from Seismic Data

Abstract

Grau, G., Montadert, L., Delteil, R. and Winnock, E., 1973. Structure of the European continental margin between Portugal and Ireland, from seismic data. In: S. Mueller (Editor), The Structure of the Earth's Crust, based on Seismic Data. Tectonophysics , 20 (1–4): 319–339. The continental margin reviewed in this paper corresponds in almost all its parts to a Hercynian platform which was more or less structured during the Mesozoic and Cenozoic in association with the formation of the Atlantic Ocean. In the areas above water and the continental shelves, this Hercynian platform either has a thin sedimentary covering (Galicia, Armorica, West Ireland, Porcupine Bank) or, on the contrary, has been extensively depressed by distension movements accompanied with the formation of thick Mesozoic and Cenozoic basins connected with the oceanic domain (West Portugal, Basco-Cantabrian zone, Adour Basin, Parentis Basin, Western Approaches Basin, North Celtic Sea Basin, Porcupine Seabight Basin). In addition, the Early Cenozoic Pyrenean-Alpine compression movements had repercussions on the structure of the north Spanish margin. From the structural standpoint, the main features of the margin are linked both to the deep indentation of the Bay of Biscay and to the existence of more or less collapsed blocks prolonging the continental domain. These blocks are visible either in the topography (Porto and Vigo seamounts, Galicia Banks, Asturian marginal shelf, Porcupine Bank) or solely by seismic reflection (Trevelyan Escarpment). Thick marginal sedimentary basins exist at the foot of the slope.