The current state and 125 kyr history of permafrost on the Kara Sea shelf: modeling constraints

Abstract

Abstract. The evolution of permafrost on the Kara shelf is reconstructed for the past 125 kyr. The work includes zoning of the shelf according to geological history; compiling sea level and ground temperature scenarios within the distinguished zones; and modeling to evaluate the thickness of permafrost and the distribution of frozen, cooled and thawed deposits. Special attention is given to the scenarios of the evolution of ground temperature in key stages of history that determined the current state of the Kara shelf permafrost zone: characterization of the extensiveness and duration of the existence of the sea during stage 3 of the marine oxygen isotope stratigraphy (MIS-3), the spread of glaciation and dammed basins in MIS-2. The present shelf is divided into areas of continuous, discontinuous-to-sporadic and sporadic permafrost. Cooled deposits occur at the western and northwestern water zones and correspond to areas of MIS-2 glaciation. Permafrost occurs in the periglacial domain that is within a zone of modern sea depth from 0 to 100 m, adjacent to the continent. The distribution of permafrost is mostly sporadic in the southwest of this zone, while it is mostly continuous in the northeast. The thickness of permafrost does not exceed 100 m in the southeast and ranges from 100 to 300 m in the northeast. Thawed deposits are confined to the estuaries of large rivers and the deepwater part of the St. Anna trench. The modeling results are correlated to the available field data and are presented as a geocryological map. The formation of frozen, cooled and thawed deposits of the region is inferred to depend on the spread of ice sheets, sea level, and duration of shelf freezing and thawing periods.

Detecting subsea permafrost layers on marine seismic data: An appraisal from forward modelling

“…Soviet scientists originally discovered subsea permafrost in the 19th century, with the first map of subsea permafrost distribution off the USSR coastline being released just before the Second World War (Parkhomenko, 1937). With interest to develop offshore hydrocarbon resources of the Arctic, subsea permafrost research eventually took off in the early 1970s in the Beaufort Sea and the Kara Sea (Angelopoulos et al., 2020; Gavrilov et al., 2020). In the Canadian Beaufort Sea, Mackay (1972) was the first to posit the widespread occurrence of subsea permafrost.…”

Permafrost and Gas Hydrate Stability Zone of the Glacial Part of the East-Siberian Shelf

“…Such a scenario includes a family of paleotemperature curves. We construct paletemperature curves for different isobaths and regions based on the shelf zoning in terms of bathymetry, tectonic structures, and geological development [10,11,54]. This method based on transformation of the isotope curve of Vostok station (East Antarctic), was widely used earlier [6,9,16] and is being used in a modified form now [19,23,25].…”

“…Within the glacial area, the glacioisostatic curve is considered as one of the main parameters to reconstruct the hypsometry of the glacial bed, shores, and their position relative to the sea level. It characterizes the course of glacioisostatic movements in time, that is, the progress of changes in the glacial bed and shores hypsometry [54].…”

Modeling of the Arctic subsea permafrost thawing under possible climate warming

“…The ocean level changes during the glacial-interglacial cycles caused transition of the Arctic shelf areas into the land and formation of frozen deposits in the sediments [1][2][3][4][5][6]. Since the last glacial maximum (LGM), approximately 3.5 × 10 6 km 2 of permafrost soils have been inundated as a result of sea level rise by 100-120 m [7,8].…”