The comprehensive analysis of potential field data and recent seismic data revealed two systems of fractures bounding horsts and grabens in terms of the Mendeleev Ridge. The northern part of the ridge is marked by development of pull-apart structures indicating the former existence of oblique extension settings. The area between Mendeleev and Alpha ridges is occupied by a wide NW‒SE–extending sinistral strike-slip zone. It is concluded that these ridges are of continental origin representing former parts of Arctida (Hyperborea) in the pre-Cretaceous time. The ridges were separated and their crust significantly altered during Cretaceous tectono-magmatic activation in the region.