New data on the structure of the Laptev Sea flank of the gakkel ridge (Arctic Ocean)

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The article provides new data on the structure of the Laptev Sea flank of the Gakkel Ridge. The intensive supply of clastic material from the shelf of the Laptev Sea leads to the development of a thick alluvial cone at the continental foot, which determines the structure of the bottom topography. In the northwestern direction, the influence of the fan decreases and tectonics becomes the main relief-forming factor. The bathymetric survey traced the asymmetrical rift valley of the Gakkel Ridge, the western side of which is complicated by terraces. The presence of fault structures, bottom subsidence and intensive sediment supply, and the widespread development of landslide processes indicate high neotectonic activity of the Laptev Sea flank of the Gakkel Ridge. For the first time in this region, numerous carbonate formations have been discovered, the authigenic cement of which is represented by magnesian calcite or aragonite with an admixture of terrigenous material. Palynological and micropaleontological analysis of carbonate formations indicates the Quaternary formation of authigenic carbonate cement. An important role in the formation of authigenic carbonates was played by diagenetic solutions coming from the sedimentary cover together with methane and products of oxidation of gases and organic matter. Authigenic carbonates were deposited mainly in isotopic equilibrium with bottom water at a temperature of about 0°C. The negative correlation between 87Sr/86Sr and δ13C indicates the presence of at least two different sources of carbonate-forming solutions.