Home – Home – Jornals – Russian Geology and Geophysics 2002 number 2

The plate of the Sea of Okhotsk is considered as an old oceanic volcanic plateau with tectonic boundaries. Its eastern and western boundaries are formed by right-lateral strike-slip faults; in the north, the plate is bounded by a Middle Cretaceous subduction zone, and the southern boundary is delineated by the ongoing subduction of the Pacific plate beneath Eurasia. On the plate margins (eastern Sakhalin, Taigonos Peninsula, Kuyul Ridge, and Omgon Peninsula in western Kamchatka), relict Middle Jurassic-Lower Cretaceous oceanic crust is exposed in accretionary prisms. The South Okhotsk basin is the largest fragment of the Kula oceanic plate.
A volcanic uplift in the center of the Okhotsk plate is identified as the Okhotsk volcanic plateau. In terms of geophysics, the plateau is similar to other volcanic plateaus, such as Ontong-Jawa, Shatsky, Hess, etc. It is hypothesized that the Okhotsk volcanic plateau formed north of the mid-ocean ridge, within the Kula plate, in response to the late Jurassic-early Cretaceous activity of a hot mantle plume in the region of the triple junction of the Kula, Pacific, and Faralon plates. As a result of the northward motion of the Kula plate with the Okhotsk plateau, the latter blocked subduction beneath the Okhotsk-Chukchi volcanoplutonic belt in the late Turonian. Subduction zones blocked by oceanic volcanic structures are of broad occurrence near accretionary fold-nappe belts.