A High Arctic inner shelf–fjord system from the Last Glacial Maximum to the present: Bessel Fjord and southwest Dove Bugt, northeastern Greenland
<p>The Greenland Ice Sheet (GrIS) responds rapidly to the present climate; therefore, its response to the predicted future warming is of concern. To learn more about the impact of future climatic warming on the ice sheet, decoding its behavior during past periods of warmer than present climate...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-07-01
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| Series: | Climate of the Past |
| Online Access: | https://cp.copernicus.org/articles/19/1321/2023/cp-19-1321-2023.pdf |
| Summary: | <p>The Greenland Ice Sheet (GrIS) responds rapidly to the present climate;
therefore, its response to the predicted future warming is of concern. To
learn more about the impact of future climatic warming on the ice sheet,
decoding its behavior during past periods of warmer than present climate is
important. However, due to the scarcity of marine studies reconstructing ice
sheet conditions on the Northeast Greenland shelf and adjacent fjords, the
timing of the deglaciation over marine regions and its connection to forcing
factors remain poorly constrained. This includes data collected in fjords
that encompass the Holocene thermal maximum (HTM), a period in which the
climate was warmer than it is at present. This paper aims to use new
bathymetric data and the analysis of sediment gravity cores to enhance our
understanding of ice dynamics of the GrIS in a fjord and inner shelf
environment as well as give insight into the timing of deglaciation and
provide a palaeoenvironmental reconstruction of southwestern Dove Bugt and
Bessel Fjord since the Last Glacial Maximum (LGM). North–south-oriented
glacial lineations and the absence of pronounced moraines in southwest Dove
Bugt, an inner continental shelf embayment (trough), suggest the southwards
and offshore flow of Storstrømmen, the southern branch of the Northeast
Greenland Ice Stream (NEGIS). Sedimentological data suggest that an ice
body, theorized to be the NEGIS, may have retreated from the region slightly
before <span class="inline-formula">∼</span> 11.4 cal ka BP. The seabed morphology of Bessel
Fjord, a fjord terminating in southern Dove Bugt, includes numerous basins
separated by thresholds. The position of basin thresholds, which include
some recessional moraines, suggest that the GrIS had undergone multiple
halts or readvances during deglaciation, likely during one of the cold
events identified in the Greenland Summit temperature records. A minimum age
of 7.1 cal ka BP is proposed for the retreat of ice through the fjord to or
west of its present-day position in the Bessel Fjord catchment area. This
suggests that the GrIS retreated from the marine realm in Early Holocene,
around the onset of the HTM in this region, a period when the mean July
temperature was at least 2–3 <span class="inline-formula"><sup>∘</sup></span>C higher than at present and remained at
or west of this onshore position for the remainder of the Holocene. The
transition from predominantly mud to muddy sand layers in a mid-fjord core
at <span class="inline-formula">∼</span> 4 cal ka BP may be the result of increased sediment
input from nearby and growing ice caps. This shift may suggest that in the
Late Holocene (Meghalayan), a period characterized by a temperature drop to
modern values, ice caps in Bessel Fjord probably fluctuated with greater
sensitivity to climatic conditions than the northeastern sector of the GrIS.</p> |
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| ISSN: | 1814-9324 1814-9332 |