Submarine wide-angle seismic experiments in the High Arctic: The JASMInE Expedition in the slowest spreading Gakkel Ridge

The Gakkel Ridge in Arctic Ocean is the slowest spreading ridge on earth, representing the end-member of global oceanic crustal accretion at all spreading rates. Wide-angle seismic experiment is the most directive way to map the lithospheric structure, which in turn provides key information about the oceanic crustal formation and driving mechanism. In 2021, the JASMInE Expedition carried out the first wide-angle reflection/refraction seismic experiment along the Gakkel Ridge from 75° to 102°E, which was thought to be impossible in Arctic with high ice cover. A series of domestic equipment with specific adaptions for High Arctic were used during this expedition, as well as modifications to conventional technologies and performances. 43 Ocean Bottom Seismometers were deployed on the seafloor, and 42 of them were successfully recovered, forming two seismic profiles along and perpendicular to the Gakkel Ridge with a total length of 400 km. The recorded seismic data are in high quality, which could be used to obtain a reliable lithospheric structure of the slowest Gakkel Ridge.