Riftogenesis in the Arctic: Processes, Evolution Trend, and Hydrocarbon Generation

• Published in: Lithology and Mineral Resources Vol. 57; no. 2; pp. 95 - 120
• Main Authors: Chamov, N. P., Sokolov, S. Yu
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.04.2022; Springer Nature B.V
• Subjects: Arctic zone; Earth and Environmental Science; Earth rotation; Earth Sciences; Equator; Evolution; Fault lines; Faults; Gas hydrates; Gases; Hydrates; Hydrocarbons; Ice environments; Lithosphere; Mineral Resources; Mineralogy; North Pole; Outflow; Permafrost; Rift zones; Rifting; Sedimentology; Serpentinization; Upper mantle; Arctic region; degassing; rifting; Arctic; hydrocarbons; igneous province
• ISSN: 0024-4902; 1608-3229; 1573-8892
• DOI: 10.1134/S0024490222020031

The article examines the regional patterns of rifting in the Arctic and assesses the impact of large (supra-regional) rift systems on the geological evolution of the region. Against the background of the description of main Arctic structures, the Atlantic–Arctic rift system (AARS) is described as a tectonotype of a large planetary geophorm that has evolved from continental rifting to spreading proper with the development of a full-fledged ocean. The main properties of this system are its development towards the North Pole, the longitudinal orientation of the rifts, their separation by latitudinal faults, and predominantly sinistral shear displacement of individual segments. We believe that such a structure reflects the influence of the rotational factor on distribution of lithospheric masses of the Earth. Their tendency to the equilibrium position relative to the rotation axis is implemented by movements towards the equator and along it. The outflow of masses to low latitudes makes possible the growth of the rift system, but does not contribute to its further development after reaching the Pole. This phenomenon is of general nature and determines the development of all longitudinal rift systems, which leads to their spatial convergence and attenuation of dynamics in the circumpolar space. Within the Arctic region, in addition to the Atlantic–Arctic system, areas of possible termination of the West Siberian, Okhotsk–Verkhoyansk, and East Pacific rift systems are considered. It is assumed that their evolution initiated the destruction of the continental lithosphere of the Arctic region and determined the subsequent transformations of its structure. Special attention is paid to the problems of the possible influence of rifting on the hydrocarbon generation due to serpentinization of hyperbasites, when the lithosphere is penetrated by faults to the upper mantle depths, as well as on the remobilization of gases as a result of the disturbance of both gas hydrate reservoirs and permafrost. It is shown that the greatest generation of methane is generally associated with the development of faults in the cold lithosphere and serpentinization of mantle rocks.