Dating of the Sedimentary Cover Reflectors and Evaluation of the Sedimentation Rates in the Late Pliocene–Quaternary in the King’s Trough and Vicinity (the North Atlantic)

Based on the results of the expedition works during the 55th and 57th cruises of the R/V Akademik Nikolai Strakhov in the area of the King’s Trough mesostructural complex (the eastern flank of the MAR), seismoacoustic profiling data of the upper part of the sedimentary cover are obtained. Reference reflectors, which were correlated with the DSDP 608 and IODP U1312 deep-sea drilling holes, are identified from the seismoacoustic sections. The sections cover the entire Quaternary sediment record (glacial cycles) and a part of the Upper Pliocene sediment record. Sedimentation rates within the different structures of the King’s Trough are calculated as a result of the works. During the past 1.5 Ma, sedimentation rates have been slightly different across the study area from background sedimentation rates, while earlier sedimentation rates were recorded to exceed the background ones by several times. There is a period of sharply increased sedimentation rates (up to 180 m/My) at ca. 1.5 Ma, which may be due to abrupt climate changes and ocean level fluctuations. Prior to the onset of the Mid-Pleistocene Transition ~1.5 Ma ago, a bottom current might have flowed along the bottom of the western part of the King’s Trough, which caused high sedimentation rates in the bottom of the trough. The current stopped after the onset of the transition, which could be due to regional restructuring of the Atlantic Meridional Overturning Circulation. These conclusions are correlated with sedimentation rates and changes in ocean surface temperature based on the data from IODP U1313.