Settings of current sedimentation on the underwater slope of Buor-Khaya bay (Laptev sea)

Abstract

Nowadays, the Arctic shelf is of increasing interest due to its large reserves of hydrocarbons and other mineral resources. Meanwhile, current knowledge about the processes occurring in the Arctic is still extremely inadequate. There is still not enough data on natural processes within permafrost, which raises many problems and discussions around regional issues. Therefore, new scientific information can further promote the study of the Arctic nature. This study was aimed to identify the specific features of sedimentation and organic matter transformation in the coastal zone of the Arctic seas based on long-term observations. The objects of the study are suspended matter and bottom sediments, including organic carbon content (Corg) and its isotope composition as markers of lithodynamics of the modern depositional environment. Bottom sediments samples were investigated for grain-size composition, organic carbon content and isotopic composition. Furthermore, spatio-temporal variability of the suspended matter distribution in the water column was estimated. Conclusions: for the ice-free period, there are two typical stable turbidity maxima with a suspended matter content ranging from 6,5 to 594 mg/l. Towards the continental slope, the replacement of sandy-aleuritic sediments with clays of continental slope, avandelt bottom, and thermoabrasive-accumulative terrace is accompanied by an increase in organic carbon values from 0,4 to 5,4 % with winter values ranging from 0,6 to 9,3 %. Isotopic composition of organic carbon in the bottom sediments varied from -27,9 to -22,7.

Keywords

• East Siberian shelf
• Laptev Sea
• permafrost
• thermal abrasion
• bottom sediments
• suspended matter