Chapter 25 Tectonic setting, structure and petroleum geology of the Siberian Arctic offshore sedimentary basins

Abstract

AbstractThe paper summarizes the results of geological and geophysical studies of the Siberian Arctic Shelf (Laptev, East Siberian and Chukchi seas), which is one of the largest continental shelves on Earth. This region consists of as many as 22 significant sedimentary basins of variable age and genesis which are expected to bear significant undiscovered volumes of hydrocarbons. Two major groups of the basins are identified based on the age of the underlying crustal basement: (1) post-Hauterivian/Barremian basins resting on the Late Mesozoic folded basement; and (2) older (Late Palaeozoic to Early Mesozoic?) basins preserved outboard of the Late Mesozoic deformational front in the northern part of the East Siberian and Chukchi seas. At least two significant tectonic events caused the overall tectonic pattern of the shelf as well as formation and structural styles of its individual crustal domains and the sedimentary basins: (1) Late Mesozoic convergence and subsequent collision of the Arctic Alaska–Chukchi Microplate with the Verkhoyansk–Kolyma/Omolon margin of the North Asia Continent around 130–125 Ma (the Verkhoyansk–Brookian compressional event); and (2) a series of Cretaceous and Cenozoic extensional events related to the origin of the Arctic oceanic basins. Based on 2D regional multichannel seismic reflection data constrained by onshore geology, plate tectonic models and inter-regional correlations, as well as on gravity and magnetic grids, the structural styles, lithostratigraphy and possible hydrocarbon systems of the offshore sedimentary basins are considered.