Some remarks on the continental margins in the Aquitaine and French Pyrenees

AbstractFrom the Triassic to the Late Eocene, the Iberian Peninsula underwent three successive rotations with respect to the stable European plate, (a) Prior to the Late Aptian, a nearly 150 km southwestward motion resulted in stretching and thinning of the continental crust beneath the North Pyrenean zone, the Aquitaine Basin and the Bay of Biscay continental margins (rifting). Distensive structures trended 90° N to 130° N, and were shifted by 30° N to 50° N transform faults. (b) During the Late Aptian to Santonian interval, an approximately 400 km southeastward motion resulted in the opening of the Bay of Biscay and sinistral slipping of Iberia along the North Pyrenean transform zone (drifting), (c) During palaeocene–Eocene time, a 150 km northwestward convergent motion resulted in limited subduction of the oceanic crust of the Bay of Biscay beneath the Iberian plate, and folding of the Pyrenean chain. The folded belt resulted from squeezing of the former European and Iberian margins (rifted or transform margins, depending on the segment considered).