Fluidogenic landforms on the Arctic shelves

Abstract

The paper summarizes and systematizes available data on geological and geomorphologic structure of fluidogenic landforms on the Arctic shelves, in particular, pockmarks, pingo-like features, domes and craters. A small-scale map of the spatial distribution of fluidogenic landforms has been compiled. Geographical patterns of distribution of different types of fluidogenic landforms in the Arctic seas were identified, as well as main factors and conditions that determine their localization, morphology and modern activity. It is shown that fluidogenic landforms are complex formations with a multi-component source of fluids. Their distribution and accompanying gas manifestations in bottom sediments and water column are determined by complex combinations of factors. Among them the most significant are distribution and thickness of subaquatic permafrost and subpermafrost and the near-surface deep-sea gas hydrates. The amount of fluidogenic landforms at the bottom is influenced by specific features of oil and gas bearing structures and rocks with reservoir properties, as well as the influx of fresh land waters along the base of permafrost on the shelf, the degree of salinity of bottom sediments and the temperature of near-bottom water. In addition, fluidogenic morpholithogenesis is facilitated by the presence of structural channels for the influx of fluids to the surface in the form of faults and gas pipes in bottom sediments with the possible contribution of the jet degassing effect to the new formation of frozen rocks, accompanied by bottom heaving. Morphological differences in the structure of fluidogenic landforms are associated, in addition to the factors indicated above, with the history of the geological development of the shelf, in particular, with the time of submersion during the Holocene transgression and the impact of glaciation.