Riphean rifting and major Palaeoproterozoic crustal boundaries in the basement of the East European Craton: Geology and geophysics

The East European Craton, which occupies the northeastern half of the European continent, is characterized by the presence of giant, even transcratonic systems of Riphean (Meso- to Neoproterozoic) rifts (aulacogens). The largest of these Riphean rift systems tend to follow the course of Palaeoproterozoic sutures and junction zones that subdivide the craton into three crustal segments with autonomous development histories. These segments, named Fennoscandia, Volgo-Uralia and Sarmatia, are marked by distinct T-MAGSAT anomalies. Genetically, the intersegment junction zones represent different types of collisional and accretional interaction between the component crustal segments of the craton. In accordance with this, the Riphean rift systems vary in width, the presence or absence of Moho uplifts, and other properties like, for instance, heat flow values. However, all of them follow belts of weakly magnetized crust studded with local magnetic maxima due to the presence of mafic rocks associated with the rifting. The rift system-intersegment junction zone relationships, in consequence, similarly represent a range of variation and cannot be referred to one single model.