The Oka plateau in the neotectonic framework of southern East Siberia

The Oka plateau exists as a moderately elevated (2400 m) intermontane area bounded by the major East Sayan dome, the Main Sayan Fault, and the Baikal Rift system, in the zone of the rift strike break. The plateau, which has a block structure, and its surroundings show specific features of recent geo dynamics, including seismicity and distribution of Cenozoic basalts. These specific features are related to the position of the region over a hotspot swell along 100 E, which corresponds to a column of low-density material co nnecting a sublithospheric asthenolith with the lower mantle.