The north - eastern boundary of the Baikal rift zone

The Baikal rift zone is defined on its NE side by the Olyekma-Amur system of NW/SE-striking transverse lineaments. Transverse faults also separate the north-eastern part of the rift zone into the Chara and Tokko sections. The former shows a typical range of neotectonic forms which include (from NW to SE): the inclined horsts of the Kodar ridge; an axial system of grabens and interbasin faults and a marginal dome. The Tokko section is located within a sector of the Olyekma-Amur system of lineaments. Here, the neotectonic forms are smaller and a degradation of the NW flank of the rift zone has taken place. A large marginal step defines the south-eastern flank. It is considered that these structural modifications relate to changes in the anomalous mantle protrusion near the north-eastern boundary of the rift zone.