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Evidence for an ice shelf covering the central Arctic Ocean during the penultimate glaciation.

https://arctichealth.org/en/permalink/ahliterature269367
Source
Nat Commun. 2016;7:10365
Publication Type
Article
Date
2016
Author
Martin Jakobsson
Johan Nilsson
Leif Anderson
Jan Backman
Göran Björk
Thomas M Cronin
Nina Kirchner
Andrey Koshurnikov
Larry Mayer
Riko Noormets
Matthew O'Regan
Christian Stranne
Roman Ananiev
Natalia Barrientos Macho
Denis Cherniykh
Helen Coxall
Björn Eriksson
Tom Flodén
Laura Gemery
Örjan Gustafsson
Kevin Jerram
Carina Johansson
Alexey Khortov
Rezwan Mohammad
Igor Semiletov
Source
Nat Commun. 2016;7:10365
Date
2016
Language
English
Publication Type
Article
Abstract
The hypothesis of a km-thick ice shelf covering the entire Arctic Ocean during peak glacial conditions was proposed nearly half a century ago. Floating ice shelves preserve few direct traces after their disappearance, making reconstructions difficult. Seafloor imprints of ice shelves should, however, exist where ice grounded along their flow paths. Here we present new evidence of ice-shelf groundings on bathymetric highs in the central Arctic Ocean, resurrecting the concept of an ice shelf extending over the entire central Arctic Ocean during at least one previous ice age. New and previously mapped glacial landforms together reveal flow of a spatially coherent, in some regions >1-km thick, central Arctic Ocean ice shelf dated to marine isotope stage 6 (~140?ka). Bathymetric highs were likely critical in the ice-shelf development by acting as pinning points where stabilizing ice rises formed, thereby providing sufficient back stress to allow ice shelf thickening.
PubMed ID
26778247 View in PubMed
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Remobilization of Old Permafrost Carbon to Chukchi Sea Sediments During the End of the Last Deglaciation.

https://arctichealth.org/en/permalink/ahliterature299553
Source
Global Biogeochem Cycles. 2019 Jan; 33(1):2-14
Publication Type
Journal Article
Date
Jan-2019
Author
Jannik Martens
Birgit Wild
Christof Pearce
Tommaso Tesi
August Andersson
Lisa Bröder
Matt O'Regan
Martin Jakobsson
Martin Sköld
Laura Gemery
Thomas M Cronin
Igor Semiletov
Oleg V Dudarev
Örjan Gustafsson
Author Affiliation
Department of Environmental Science and Analytical Chemistry (ACES) Stockholm University Stockholm Sweden.
Source
Global Biogeochem Cycles. 2019 Jan; 33(1):2-14
Date
Jan-2019
Language
English
Publication Type
Journal Article
Abstract
Climate warming is expected to destabilize permafrost carbon (PF-C) by thaw-erosion and deepening of the seasonally thawed active layer and thereby promote PF-C mineralization to CO2 and CH4. A similar PF-C remobilization might have contributed to the increase in atmospheric CO2 during deglacial warming after the last glacial maximum. Using carbon isotopes and terrestrial biomarkers (?14C, d13C, and lignin phenols), this study quantifies deposition of terrestrial carbon originating from permafrost in sediments from the Chukchi Sea (core SWERUS-L2-4-PC1). The sediment core reconstructs remobilization of permafrost carbon during the late Allerød warm period starting at 13,000 cal years before present (BP), the Younger Dryas, and the early Holocene warming until 11,000 cal years BP and compares this period with the late Holocene, from 3,650 years BP until present. Dual-carbon-isotope-based source apportionment demonstrates that Ice Complex Deposit-ice- and carbon-rich permafrost from the late Pleistocene (also referred to as Yedoma)-was the dominant source of organic carbon (66 ± 8%; mean ± standard deviation) to sediments during the end of the deglaciation, with fluxes more than twice as high (8.0 ± 4.6 g·m-2·year-1) as in the late Holocene (3.1 ± 1.0 g·m-2·year-1). These results are consistent with late deglacial PF-C remobilization observed in a Laptev Sea record, yet in contrast with PF-C sources, which at that location were dominated by active layer material from the Lena River watershed. Release of dormant PF-C from erosion of coastal permafrost during the end of the last deglaciation indicates vulnerability of Ice Complex Deposit in response to future warming and sea level changes.
PubMed ID
31007381 View in PubMed
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