Present day Jakobshavn Isbrae (West Greenland) close to the Holocene minimum extent

QUATERNARY SCIENCE REVIEWS

卷:246

Article

Kajanto, Karita^1,2  Seroussi, Helene³  de Fleurian, Basile^1,2  Nisancioglu, Kerim H.^1,2,4 

[1] Univ Bergen, Dept Earth Sci, Jahnebakken 5, N-5007 Bergen, Norway

[2] Bjerknes Ctr Climate Res, Jahnebakken 5, N-5007 Bergen, Norway

[3] CALTECH, Jet Prop Lab, Pasadena, CA USA

[4] Univ Oslo, Ctr Earth Evolut & Dynam, Oslo, Norway

关键词: Jakobhsavn Isbrae;    Holocene;    Glaciology;    Greenland;    Marine terminating glaciers;    Paleo ice-sheets;    Modeling;    Ice-ocean interaction;   

DOI  :  10.1016/j.quascirev.2020.106492

来源: Elsevier

【 摘 要 】

Marine terminating glaciers evolve on millenial timescales in response to changes in oceanic and atmospheric conditions. However, the relative role of oceanic and atmospheric drivers remains uncertain. The evolution of marine terminating glaciers under the warmer than present Holocene Climate Optimum climate can give important insights into the dynamics of ice streams as the climate evolves. The early Holocene evolution of Jakobshavn Isbrx, from the Last Glacial Maximum extent up to 8.2 ka BP is well constrained by geomorphological studies in the area. However, the Holocene minimum extent of the glacier is unknown. Here, we use a high-resolution regional ice sheet model to study the retreat and readvance of Jakobshavn Isbrx from the Mid-Holocene to the Little Ice Age. This model of Jakobshavn Isbra accurately tracks the terrestrial ice margin and agrees with available estimates of marine grounding line evolution. We find that the Holocene minimum extent of both the terrestrial ice margin and the grounding line, reached at 6-5 ka BP, is close to the present day extent of the glacier. We also find that the glacier is currently located close to a tipping point, from beyond which readvance would require a longer and more significant cooling than the Little Ice Age. We assess the importance of the ocean forcing in explaining the Holocene evolution of Jakobshavn, and find that cooling within the fjord during the Mid-Holocene is critical for the glacier to readvance. This finding emphasizes the role of ocean forcing when trying to understand the millenial scale evolution of marine terminating glaciers. (C) 2020 The Author(s). Published by Elsevier Ltd.

【 授权许可】

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