Plate reconstruction of the Bay of Biscay

Abstract

A plate reconstruction of the Bay of Biscay to a predrift stage is proposed on the basis of (1) an Aptian-Albian tectonic pattern of the Basque-Cantabrian region in northern Spain, which suggests major left-lateral strike-slip movements, and (2) a continental margin that matches predrift stages. Plate reconstruction results from the juxtaposition of the two continental margins of the Bay of Biscay, so that the eastern North Spanish margin lies laterally adjacent to the southwest French margin (Landes Plateau) and the western North Spanish margin borders the eastern part of the Meriadzek Terrace in the Armorican margin. The restoration obtained is supported by both the implied amount of clockwise rotation of Iberia (37°, very close to the 35° suggested by paleomagnetism) and the positive matching of north-south-oriented transform structures from the South Biscay margin with northeast-southwest-oriented transform structures from the North Biscay margin.