Morphology and Sedimentary Cover Structure of Long Segments of the Gakkel Ridge

The rift valley of the Gakkel Ridge was divided into three segments according to sub-bottom profiling and seismoacoustic studies carried out by R/V Akademik Fedorov at the Gakkel Ridge in 2019–2020, and on seismic data of 2011–2015. West of 75° E, the rift valley crosses the Gakkel Ridge approximately in the middle, as was expected based on the assumption that the rift valley runs along the spreading axis that formed this ridge. East of 75° E, the rift valley shifts to the southwestern edge of the ridge, and, thus, it can be concluded that the spreading axis jumped to its present position relatively recently (in the Pliocene). Finally, to the south of the the Gakkel caldera (about 120° E, 81° N), the rift valley is manifested in the sections as a young graben through many kilometers of sediments.