Tectono-stratigraphic setting of the southern slope nappes of Montagne Noire

The Montagne Noire is a segment of the southern French external zones of the Variscan belt. This branch of the orogen resulted from the collision of several microcontinents (that form the present internal zones), with a prong of Gondwana. This collision caused the extrusion of the sedimentary content of the ‘Centralian Ocean’, which was stacked on the craton as a pile of thrust nappes. Later movements deformed the entire framework in a large anticline. The nappes are nowadays cropping out as two separate zones : the northern and southern slopes of Montagne Noire. Paleozoic successions cropping out on the southern slope nappes belong to two sedimentary cycles. The Cambto-Ordovician cycle corresponds to the post-Cadomian distension : the progressive setting of a passive margin on the edge of the Gondwana craton and the opening of the ‘Centralian Ocean’. The Devono-Visean cycle corresponds to the formation of a foreland basin at the front of the Variscan orogen.