Comparative tectonics of the White Sea paleorift system and other continental rifting systems

Abstract

Research subject. The Riphean paleorift system of the White Sea, most of which is overlain by the waters of the White and Barents Seas and the platform cover of the East European Platform. This allowed numerous researchers to classify it as an aulacogen. The system was revealed by geophysical methods in the relief of the crystalline basement of the platform in the form of a frame of deep extended trenches of northwestern strike, subparallel to the edge of the East European platform.Materials and methods. Personal observations of the authors within the Onega-Kandalakcha paleorift, Baikal rift zone; a detailed study of seismostratigraphic sections of these zones; extensive literature data on the structure of modern rift zones. A comparative analysis of the structure of the most studied and currently active Baikal and East African rift systems, as well as the Karoo rift system of the Late Paleozoic origin with the paleorift system of the White Sea.Results. The following types of structural parageneses, which are characteristic of both modern rift systems and ancient paleorift systems, were identified. 1. Genetic relationship (inheritance?) of riftogenic structures with more ancient basement structures. 2. Structural paragenesis of concentric complexes in rift propagation zones. 3. Comparability of the area of horizontal extension of the lithosphere of the White Sea paleorift system with extension zones of modern continental rifts. 4. The fundamental similarity of the structure: the complex of paleorifts of the White Sea with modern continental rift systems: the presence of long deep trough segmentation of grabens and semi-grabens separated by bridges, which were accommodation zones with polarity reversal along the strike of the rift zone, displacement of the rift relative to the mantle ledge, the existence of a gently dipping normal fault (detachment), etc.Conclusion. The riftogenic nature of the aulacogens in the northeastern segment of the East European Platform has been confirmed.