The Okhotsk-Chukotka volcanic belt problem of the age in the light of data on the different timing of the formation of its links

Abstract

The main features of the structure are considered and the stages of studying the age of the Okhotsk-Chukotka volcanic belt (OCVB) are noted, the problems faced by researchers dealing with the time of the foundation and completion of the formation of this global volcanic structure are emphasized. It is shown that the results of high-precision (U/Pb and 40Ar/39Ar) dating of volcanogenic rocks and their intrusive comagmates accumulated over the last two decades indicate the presence of significant time gaps between the formation of magmatogenic complexes of the suprasubduction type identical in composition and position in the section in three large fragments of the OCVB: the main arc link and the flanking zones adjacent to it, which indicates the different timing of the formation of the components of the volcanogen. The formation of the main arc link (the Taui-Chaun arcocline) was delayed by 9 (?)–11 million years against the West Okhotsk flank zone and 5 (?)–8 million years ahead of the East Chukchi zone.
The data obtained, together with information on the Albian magmatism of the North-East of Russia, suggest that in the Alb, during the development in the conditions of the transform continental margin of that part of the region, which later became the main arc link of the OCVB, the area of the future west-southwest link of the belt (West Okhotsk flank zone) was the scene of active volcanism convergent edge mode.