Detailing the time frame of geodynamic processes on Sakhalin Island in the Cenozoic

Abstract

Forming of the geological structure of Sakhalin Island in the Cenozoic is caused by subsurface mantle flows described by the upper mantle return cell model. The proposed mechanism of the return cell continues to play a crucial role in the development of the island structure at the present stage. It is shown that the island’s development is currently taking place in a transpressive environment. This situation is the result of the rotation of the Okhotsk lithospheric plate counterclockwise (which began in the Middle Eocene) and the collision between the Amur and Okhotsk lithospheric plates, which began in the Late Pliocene — Early Quaternary period. Based on the correlation of tectonic events in East Asia and Western Pacific, the time of the Hokkaido-Sakhalin system of dextral strike-slips was clarified. It is estimated to be ~45 million years ago (Middle Eocene) and corresponds to the time of the beginning of rotation of the Okhotsk lithospheric plate, which caused their creation. The time of the beginning of the Sakhalin folding phase (~3 million years ago (Late Pliocene), which is a consequence of the collision of the Amur and Okhotsk lithospheric plates, has been clarified.