The current state and 125 kyr history of permafrost on the Kara Sea shelf: modeling constraints
<p>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...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-06-01
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| Series: | The Cryosphere |
| Online Access: | https://www.the-cryosphere.net/14/1857/2020/tc-14-1857-2020.pdf |
| Summary: | <p>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.</p> |
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| ISSN: | 1994-0416 1994-0424 |