IS IT GLACIOTECTONISM - INTERACTION BETWEEN EURASIAN ICE SHEETS IN NORTHERN RUSSIA?

Without doubt, the most spectacular section though Quaternary successions in the Arkhangelsk region, NW Russia is found on the northern shores of the Kanin Peninsula. The section stretches over 35-40 kilometres along the Barents Sea coast and is about 40 metres high, although 80 metres occasionally is reached. A combination of tidal coastal activity and permafrozen sediments result in strong erosion and well-exposed sections. Along with on-site studies including detailed sedimentary logs from key areas together with sampling for luminescence dating (OSL), a photo-mosaic of a 20 km long exposure between Madakhá and Krinka Rivers document the structural architecture of the cliff. Previous work suggested that marine, lacustrine and several till units are present in the section. However, using a structural approach, it seems that a major part of the section is build of stacked sediment slabs involving a single till sheet and its sorted substratum. This implies that a glacier from the Barents Sea probably dislocated Eemian sediments and till deposited by a glacier from a northwestern direction. A second ice advance, probably associated with the Kara Sea Ice Sheet later re-deformed the sediment package from the northeast. The section is capped by marine and lacustrine basin sediments and discordantly overlain by another till unit. If our preliminary hypothesis proves to be valid, northern Kanin shows an unprecedented scale of glaciotectonic dislocation including low-angle thrust and nappe structures with a lateral displacement between 20-40 kilometres. We suggest that the section at northern Kanin holds the key for understanding the intimate relationship between the Barents Sea and Kara Sea Ice Sheets in northern Russia. Actually, other sections along the coast of Kanin Peninsula and Chyorskaya Bay into the Pechora Lowland might display the same glacio-tectonic architecture within the same well-constrained time interval reflecting a major glaciodynamic event.