Geodynamics of mountains in Eastern Yakutia and opening of the Eurasian basin

The highest and longest ridges of the East Yakutian mountainous province ex ist on its periphery as the Verkhoyansk system in the west and the Chersky and Moma systems in the east. Northward, the ridges give way to the Primor' ye lowlands that grade into the Laptev Sea shelf separated from the Eurasia n ocean basin by the continental slope. The ridges of the Verkhoyansk syste m make an asymmetric arch complicated by younger normal faults. The system of the Chersky and Moma ridges is likewise an arch cut with strike-parallel rift basins (Moma, Upper Selennyakh, etc.). The Cenozoic fill of the basin s adjacent to the ridges provides evidence that rapid uplifting of the latt er started in the Oligocene. Doming in the Late Miocene-early Pliocene was accompanied by compression, which produced imbricated thrusts with horizont al displacements of up to several kilometers. In the Late Pliocene-Early Pl eistocene, the crust of the region experienced a large-scale extension resp onsible for the opening of the Moma rift and normal fautling in the Verkhoy ansk ridge. The growth of mountain ridges in Eastern Yakutia may be related to the inte raction of the Eurasian and North American plates in the Cenozoic and the o pening of the Arctic Eurasian ocean. Multiple changes in the position of th e plates' rotation poles through the Cenozoic caused alternation of extensi on and compression regimes. The opening of the Eurasia basin and the format ion of mountain ridges in Eastern Yakutia were, apparently, nearly synchron ous geodynamic events.