Graben zone 

(Cenozoic) 

(Eastern Siberian Sea and adjacent areas)

Forms continuation of the Arctic Midocean (Gakkel) Ridge onto the Asian continent. Defines the Tertiary 
and Holocene boundary between the Eurasian and North American plates. The graben zone is defined by 
gravity anomalies and a few seismic-reflection and refraction profiles. The main, narrow Bel’kov-Svyatoi 
graben extends from the western end of Kotelniy Island to Cape Svyatoi-nos and is about 500 km long and 
ranges from 25 to 30 km wide. The grabens are filled by undeformed presumably Late Cretaceous and 
Cenozoic deposits that range from 4 to 8 km thick. Crustal thickness in the graben zone ranges from 28 to 
29 km. Seismicity is diffuse throughout the area, although it seems to be associated with many of the 
grabens. REFERENCES: Volk and Gaponenko, 1981, 1984; Vinogradov, 1984; Kim, 1986; Fujita and 
others, 1990; Vinogradov and others 1992.