Ice stream retreat following the LGM and onset of the west Greenland current in Uummannaq Trough, west Greenland

Abstract

Citation for published item:heldonD gF nd tenningsD eF nd endrewsD tFF nd ¡ y gofighD gF nd rognD uF nd howdeswellD tFeF nd eidenkrntzD wFEF @PHITA 9se strem retret following the vqw nd onset of the west qreenlnd urrent in ummnnq roughD west qreenlndF9D uternry siene reviewsFD IRU F ppF PUERTF Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The deglacial history and oceanography of Uummannaq Trough, central West Greenland 24 continental shelf, was investigated using foraminiferal, sedimentological, and bathymetric 25 records together with a radiocarbon chronology, providing a timeline for the retreat of glacial 26 ice after the Last Glacial Maximum (LGM). To map ice stream retreat, data were collected from 27 cores from the outer (JR175-VC45 and JR175-VC43) and inner (JR175-VC42) Uummannaq 28 Trough. A large ice stream, fed by confluent glaciers draining the interior of the Greenland Ice 29Sheet, extended across the outer shelf during the LGM and was retreating by 15.0 cal kyr BP. 30Foraminiferal data indicate that the 'warm' West Greenland Current (WGC) was established 31 prior to 14.0 cal kyr BP, which is the hitherto earliest record of Atlantic Water found on the 32 West Greenland shelf. For each of the cores, foraminifera indicate that ice sheet retreat was 33 followed quickly by incursion of the WGC, suggesting that the warm water may have 34 enhanced ice retreat. Prior to the Younger Dryas cold event, the existing radiocarbon 35 chronology indicates that the ice sheet retreated to the mid-shelf, where it subsequently 36 stabilised and formed a large grounding-zone wedge (GZW). After the Younger Dryas, around 37 11.5 cal kyr BP, the ice retreated rapidly from the GZW and into the fjords.

Atlantic Water advection vs. glacier dynamics in northern Spitsbergen since early deglaciation

“…In the Laptev Sea, this species has been connected to Atlanticderived water from ∼ 15.4 ka onwards (Taldenkova et al, 2010). AW presence is also inferred prior to ∼ 14 ka off West Greenland (Sheldon et al, 2016a). At the margin of the Arctic Ocean, north of Svalbard, C. neoteretis showed high abundances from at least 24 ka onwards (Wollenburg et al, 2004).…”

Simulation of the Greenland Ice sheet over two glacial cycles: Investigating a sub-ice shelf melt parameterisation and relative sea level forcing in an ice sheet-ice shelf model

“…Along the SE margin, the retreat from the outer to inner shelf is highly asynchronous, with the retreat from the outer Kangerdlugssuaq trough around 17.8 kyr BP (dark blue triangle, Fig.1) (earlier than from the central east), reaching the 150 inner fjord by 11.8 kyr BP at Kangerdlugssuaq (open blue triangle, Fig.1), and by 10.8 kyr BP at Sermilik (red cross, Fig.1). It is suggested that the timing of retreat across this region is strongly influenced by the warm incursion of Irminger current The SW region of Greenland, around Disko Bugt and Uumannaq trough is one of the more extensively studied region of the ice sheets, with a range of observational data confirming the 155 grounding of the ice sheet to the continental shelf break (Winsor et al, 2015;Sheldon et al, 2016;Jennings et al, 2014;Cofaigh et al, 2013). The retreat from the outer shelf (cluster of red triangles, Fig.1) between 19.3-18.6 kyr BP is inferred to have been driven by either a change in sea level and/or an ongoing gradual rise in boreal summer insolation rather than changes in ocean temperatures.…”

“…The question of whether a change in sea level could initiate such a retreat is just one aspect that the use of a RSL forcing in this study will examine. The retreat from the outer shelf edge in the vicinity of the Uumannaq fjord (cluster of green triangles, Fig.1) was later, after 14.9 kyr BP, reaching the outer Uumannaq trough by 10.8 kyr BP (Sheldon et al, 2016). 165…”

Simulation of the Greenland Ice Sheet over two glacial–interglacial cycles: investigating a sub-ice- shelf melt parameterization and relative sea level forcing in an ice-sheet–ice-shelf model

“…The SW region of Greenland, around Disko Bugt and the Uumannaq Trough, is one of the more extensively studied regions of the ice sheet, with a range of observational data confirming that the ice sheet grounded out onto the continental shelf break (Cofaigh et al, 2013;Jennings et al, 2014;Sheldon et al, 2016;Winsor et al, 2015). The retreat from the outer shelf (cluster of red triangles, Fig.…”

“…The retreat from the outer shelf edge in the vicinity of the Uumannaq Fjord (cluster of green triangles, Fig. 1) was later, after 14.9 ka BP, reaching the outer Uumannaq Trough by 10.8 ka BP (Sheldon et al, 2016). Against this background of geological evidence, we evaluated our model results as presented in Sect.…”