Sedimentary basins of the Eastern Asia Arctic zone: new details on their structure revealed by decompensative gravity anomalies

Abstract. In the present study, structure of sedimentary basins in the Eastern Asia Arctic zone is analysed by employing the approach based on decompensative gravity anomalies. Two obtained models, differing in their initial conditions, provide thickness and density of sediments in the study area. They demonstrate essentially new details on the structure, shape and density of the sedimentary basins. Significant changes in the sedimentary thickness and the depocenter location have been found for the Anadyr basin in its continental part. Also, new details on the sedimentary thickness distribution have been revealed for the central part of the Penzhin and Pustorets basins, for the latter, the new location of the depocenter has been identified. The new model agrees well with the seismic data on the sedimentary thickness for the offshore part of the Chauna basin confirming that the method is robust. The most significant lateral redistribution of the thickness has been found for the Lower Cretaceous coal-bearing strata in the northern part of the Zyryanka basin, where the connection of two coal-bearing zones, that was not previously mapped, has been identified. Also, the new details on the sedimentary thickness distribution have been discovered for the Primorsk basin. Therefore, the new results substantially improve our knowledge about the region, since previous geological and geophysical studies were unsystematic, sparse and limited in depth. Thus, the implementation of the decompensative gravity anomalies approach provides a better understanding of the evolution of the sedimentary basins and the obtained results can be used for planning of future detailed studies in the area.