Okhotsk-Chukotka volcanic-plutonic belt 

(Early Cretaceous and Late Cretaceous, locally Paleocene) 

(Eastern Russian Northeast, units Kvi, Kpf)

Extends for 3000 km along western margin of Sea of Okhotsk. Consists of gently dipping basalt, andesite-
basalt, andesite, dacite, rhyolite, tuff, rare beds of nonmarine clastic rocks, with conglomerate, grit, and 
sandstone at the base. Local widespread silicic volcanic rock (mainly ignimbrites) and associated tonalites, 
quartz-diorite, and rare granite. To the west toward the continent, Late Cretaceous plutonic rocks grade into 
subalkalic and alkalic granite. The Okhotsk-Chukotka belt is equivalent to the East Sikhote-Alin volcanic-
plutonic belt (unit es) in the Russian Southeast, and overlies the southeastern margin of the North Asian 
craton and the Kolyma-Omolon superterrane, as well as the Chukotka, Kony-Murgal, Okhotsk, Seward, 
South-Anyui, and Zolotogorskiy terranes of the Russian Northeast. The Okhotsk-Chukotka belt is 
interpreted as a continental-margin arc marking the Albian through Campanian and locally Paleocene 
boundary of northern Asia The Paleocene part locally consists mainly of plateau theoleiitic basalt. The 
plutonic part of Okhotsk-Chukotka belt is interpreted as extending eastward across the Bering Straits into 
the Seward Peninsula in western Alaska. REFERENCES: Belyi, 1977, 1978; Filatova, 1988; Lebedev and 
others,, 1989; Bakharev, 1976; Zagruzina, 1977; Parfenov, 1984.