GEOLOGY OF THE EAST SIBERIAN SEA, RUSSIAN ARCTIC, FROM SEISMIC IMAGES: STRUCTURES, EVOLUTION, AND IMPLICATIONS FOR THE EVOLUTION OF THE ARCTIC OCEAN BASIN

Abstract

The kinematics and history of the opening of the Amerasia Basin are closely linked to the geology of the wide shelves surrounding the Arctic Ocean. In this context, multichannel seismic reflection data from the virtually unexplored shelf of the East Siberian Sea, Russian Arctic, are discussed in combination with potential field data. Three seismic marker horizons were defined and mapped. Their ages were linked to main tectonic and regional events and to onshore findings. The data reveal that there is no continuation of the large rift basins from the Laptev Shelf onto the East Siberian Shelf and there are no indications for the previously defined several hundred kilometers wide Blagoveshchensk Basin. The East Siberian Shelf is best described as an epicontinental platform that synsedimentarily subsided continuously since Late Cretaceous times with stronger subsidence to the northeast, resulting in the formation of a large depocenter. Some form of extensional/transtensional stresses affected the area and created relatively small ESE-WNW striking basins within this depocenter. These basins are filled with >6 km thick Late Cretaceous to Tertiary sediments. The general dip of the platform of the East Siberian Shelf toward the northeast may be explained by dip-slip movements along a major transform fault that is proposed by the rotation model for the opening of the Amerasia Basin. For the evolution of small sag-shaped basins within the East Siberian Depocenter we suggest a link to the opening of the Eurasia Basin instead of to the opening of the Makarov Basin.