Basement Structure and Sedimentary Cover Seismostratigraphy in the Northern Part of the Japan Basin in the Region of the Tarasov Rise (Sea of Japan)

摘要

The results of continuous seismic profiling thermodynamics performed in the northern part of the Japan Basin in the region of the Tarasov Rise and the data of a micropaleontological examination of the diatom remains encountered in the sediment samples from the rise and continental slope are presented.In the area studied,the topography of the acoustic basement features a vast rise (plateau) buried under the sedimentary cover outlined by the depth contour 5.8 s.The plateau has a relatively smooth top surface crossed by a series of rises of the acoustic basement.The two largest rises are represented by the ridges of the Tarasov Rise.The plateau is separated from the continental slope by a depression in the acoustic basement with a depth up to 6.8 s.From the end of the Middle Miocene up to the beginning of the Paleocene,the region of the plateau represented an area of active volcanism;it coincided in time with the stage of subsidence of the floor of the acoustic basement depression.At the end of the Late Miocene,the ridges of the Tarasov Rise started to sink.In the Pliocene,this process accelerated,and,at the beginning of the Pleistocene,it stopped.In the Middle Miocene-Early Pleistocene time,the portion of the continental slope adjacent to the plateau remained stable and suffered no significant vertical movements.