New Information on the Structure, Geological Development and Oil and Gas Potential of the Northwestern Territories of Yakutia and the Adjacent Shelf of the Laptev Sea

Abstract

In the XX-th century, scientific ideas prevailed on the genetic connection of the marginal Arctic territory, stretching far into the Laptev Sea shelf, with the mesozoids of the Verkhoyansk-Kolyma’s mountain-fold system. At the same time, this coastal strip of elevation was considered as the northwestern branch of this system. At the end of the last century, there have been significant changes in these views. The opinions of the geological development of the northern continental and adjacent shelf areas during the pre-Cenozoic geological epochs get very broad support under the conditions of a typical platform regime. The latest results of the seismic survey of the CDP-2D carried out in the Laptev Sea area was played an important role. The geological model of the structure and oil and gas content of the large area of the articulation of the continental land and the adjacent East Arctic shelf is justified and for the first time a preliminary characteristic of the new large Olenek-Laptevskaya oil and gas bearing region was given. The marginal structural-tectonic elements of sub latitudinal strike are constituent parts of the southern side of a large sedimentary basin, mainly located on the shelf Laptev Sea (Olenek-Laptevskaya syneclise). The tectonic regime of the concordative deflection, carried out earlier under the conditions of the passive continental margins of the Siberian Platform, was replaced with the conditions typical for the areas of interplate activation at the end of the Cretaceous and further in the Paleogene-Neogene. At the same time, the predominant stretching established earlier in the spreading zone on the continuation of the Gakkel ridge in the south-west direction was replaced by the conditions of regional subhorizontal compression. The obtained results indicate a regional continuation on the shelf of a large Riphean focus of oil and gas formation, established earlier by seismic prospecting in the northeast of the Siberian platform. As a result, it assumes the presence of a very significant hydrocarbon potential, much exceeding the high predictive estimates of past years.