A tectonic crisis affected the sedimentological evolution of the delphino-helvetic basin and its western border, the Jura platforrn (Savoie, occidental Alps), between Kimmeridgian and Valanginian times. The nature, thickness and sedimentary accumulation indicate that the internal zone of the European continental margin was still in a distension phase while an oceanic expansion period was taking place in the western Tethysian sea. The regional coast line variation curve shows five third order sedimentary cycles from the Upper Tithonian to the Upper Valanginian. When compared with global sea-level changes diagrams, three of them are affected by tectonic movements which advance, delay or even cancel the effects of eustatic variations. Similarly, they change the geometrical relationship between the Jura platform and the Subalpine basin. At first (late Kimmeridgian-early Tithonian), the western edge of the subalpine zone is marked by the development of large mudflow and debrisflow resedimentations followed from the early Berriasian onwards by the individualisation of a new palaeogeographic unit: the presubalpine zone. It is characterized by the deposition of a very thick sedimentary sequence, typical of a mainly regressive tendency leading to the progradation of the platform edge. Finally, the probable basinward tilting of the Jura platform occurred from earily Valanginian times onward.