Advance of the Greenland Ice Sheet on to north-eastern Ellesmere Island

Nature ◽  
1974 ◽  
Vol 252 (5482) ◽  
pp. 373-375 ◽  
Author(s):  
JOHN ENGLAND
1978 ◽  
Vol 15 (4) ◽  
pp. 603-617 ◽  
Author(s):  
John England

Thirty-five radiocarbon dates associated with former ice sheet margins and raised marine deposits are presented from northeastern Ellesmere Island. Along the southern margin of Hazen Plateau, and in inner Archer Fiord, a prominent morpho-stratigraphic boundary is marked by the Hazen Moraines. These moraines represent a restricted ice advance during the last glaciation and date ca. 8130 ± 200 BP. On the immediate distal side of the Hazen Moraines, eastward for 100 km towards northwestern Greenland, the majority of dates on marine limits show synchronous emergence beginning ca. 7500 BP. This zone of synchronous emergence is considered to represent an ice-free corridor isostatically unloaded between the margins of the receding Greenland and Ellesmere island ice sheets.A more widespread till, above and beyond the Hazen Moraines, extends out of Archer Fiord–Lady Franklin Bay to Robeson and Kennedy channels. This maximum ice advance is considered to predate the last glaciation on the basis of 14C and amino acid dates from ice-marginal deposits; however, alternative interpretations of the data are presented. Previous evidence suggesting an older advance of the Greenland Ice Sheet onto this coastline is confirmed. Several glaciers in the area are presently at their maximum postglacial positions.


1992 ◽  
Vol 29 (9) ◽  
pp. 1958-1980 ◽  
Author(s):  
Weston Blake Jr.

Twenty-five radiocarbon age determinations on marine molluscs, basal organic pond sediments, charred remains in archeological sites, and a variety of other materials have allowed the construction of an emergence curve for Cape Herschel, east-central Ellesmere Island (78°35′N, 74°40′W). Only a narrow fringe of land is present between the Prince of Wales Icefield and Smith Sound, yet emergence of the order of 135 m has taken place during the last 8500–8700 radiocarbon years. The highest in situ shells were collected at an elevation of 107.5 m, and ages of 8470 ± 100 BP (GSC-3314) and 8230 ± 70 BP (TO-230) were obtained on this material.The spectacular and fresh-appearing glacial sculpture along both sides of Smith Sound, coupled with the rapid emergence in Holocene time and the fact that the oldest dates on marine shells at the fiord heads to the west are 3000–4000 years younger than those at Cape Herschel, provides convincing evidence that an ice stream filled Smith Sound (> 500 m deep) during the Late Wisconsinan glacial maximum. The Smith Sound Ice Stream drained southward from the Greenland Ice Sheet and the Innuitian Ice Sheet, which were confluent over Kane Basin, and it overrode the top of Pim Island (550 m asl). Massive melt-off of ice must have been occurring at the transition from Pleistocene to Holocene time, and this melting continued until the mid-Holocene, when all investigated outlet glaciers were behind their present positions.


2004 ◽  
Vol 41 (1) ◽  
pp. 39-61 ◽  
Author(s):  
John H England ◽  
Nigel Atkinson ◽  
Arthur S Dyke ◽  
David JA Evans ◽  
Marek Zreda

During the Late Wisconsinan, a precursor of the Prince of Wales Icefield, southern Ellesmere Island, formed a prodigious ice divide of the Innuitian Ice Sheet. Initial buildup occurred after 19 ka BP, when the icefield advanced west (inland) across Makinson Inlet from margins similar to present. Subsequent reversal of flow to the east required ice divide migration to the west onto a plateau that is largely ice-free today. From this divide, a trunk glacier flowed eastward through Makinson Inlet to join the Smith Sound Ice Stream en route to nothern Baffin Bay. Westward flow from this divide filled Baumann Fiord, depositing a granite dispersal train that extends a further 600 km across the archipelago to the polar continental shelf. Deglaciation of most of Makinson Inlet occurred catastrophically at ~9.3 ka BP, forming a calving bay that thinned the Innuitian divide, thereby triggering deglaciation of most of Baumann Fiord by 8.5 ka BP. Ninety 14C dates on Holocene shells and driftwood constrain deglacial isochrones and postglacial emergence curves on opposite sides of the former Innuitian divide. Isobases drawn on the 8 ka BP shoreline rise northwest towards Eureka Sound, the axis of maximum former ice thickness. Ice margins on Ellesmere Island were similar to present from ~50–19 ka BP (spanning marine isotope stages 3 and 2). However, significant regional variation in ice extent during this interval is recorded by ice rafting from the Laurentide Ice Sheet into Baffin Bay. Later buildup of the Innuitian Ice Sheet occurred during the low global sea level that defines the last glacial maximum (18 ka BP). We also suggest that the Innuitian Ice Sheet was influenced by the buttressing and subsequent removal of the Greenland Ice Sheet along eastern Ellesmere Island.


1977 ◽  
Vol 8 (2) ◽  
pp. 180-190 ◽  
Author(s):  
W.S.B. Paterson

In the Camp Century core, the difference in oxygen isotope ratio between Wisconsin and Holocene ice seems too large to be purely a climatic effect. A more likely interpretation is that the Wisconsin ice originated at an elevation of at least 500 m above the present station. Total gas content measurements on the core suggest that the elevation difference was about 1300 m. These results are inconsistent with the present ice flow pattern. Three hypotheses are considered: (1) The Wisconsin ice originated near the crest of a high ridge connecting the Greenland ice sheet with an ice sheet on Ellesmere Island. (2) The Wisconsin flow pattern was similar to the present one but ice was much thicker and the ice margin considerably in advance of its present position. (3) The Wisconsin ice originated near the main Greenland ice divide whereas the Holocene ice originates within 50 km of the station. Glacial-geological data are sparse but do not appear to support the first hypothesis, while the uplift data have been interpreted in two widely different ways. The second hypothesis might explain the oxygen isotope values but not the gas content measurements. The third hypothesis is thus considered the most likely one. Differences between Wisconsin and Holocene flow patterns might result from changes in positions of the ice margins as a consequence of lowered sea level in the Wisconsin.


2007 ◽  
Vol 40 (3) ◽  
pp. 299-305 ◽  
Author(s):  
John England ◽  
Jan Bednarski

ABSTRACT Over seventy new 14C dates on former relative sea levels from Hall Land, northwest Greenland, and Clements Markham Inlet, northern Ellesmere Island, are combined with previous data to revise the regional isobases for this area. These isobases show : 1) a centre of maximum postglacial emergence over northwest Greenland extending to; 2) an intervening cell of lower emergence over northeast Ellesmere Island which was isostatically-dominated by the Greenland Ice Sheet; in turn, extending to 3) a higher centre of emergence over the Grant Land Mountains, northernmost Ellesmere Island, associated with the independent history of local ice caps there. Radiocarbon dates from raised marine shorelines show a 2000 year lag between glacial unloading on northwest Greenland and northernmost Ellesmere Island. This lag in glacioisostatic adjustments suggests a considerable range in the glacier response times and/or glacioclimatic regimes in this area. Throughout the area the last ice limit was ca. 5-60 km beyond present ice margins. Maximum emergence at these ice limits is marked by shorelines built into a full glacial sea which range from 124 m asl in Clements Markham Inlet to 150 m asl in Hall Land. This indicates that similar emergence (120-150 m) in other areas does not necessarily require the removal of entire ice sheets although this has been commonly assumed in the literature. The geophysical implications of this warrant consideration.


2021 ◽  
Author(s):  
Michele Petrini ◽  
Miren Vizcaino ◽  
Raymond Sellevold ◽  
Laura Muntjewerf ◽  
Sotiria Georgiou ◽  
...  

<p>Previous coupled climate-ice sheet modeling studies indicate that the warming threshold leading to multi-millennial, large-scale deglaciation of the Greenland Ice Sheet (GrIS) is in the range of 1.6-3.0 K above the pre-industrial climate. These studies either used an intermediate complexity RCM (Robinson et al. 2012) or a low resolution GCM (Gregory et al., 2020) coupled to a zero-order ISM. Here, we investigate the warming threshold and long-term response time of the GrIS using the higher-order Community Ice Sheet Model version 2 (CISM2, Lipscomb et al. 2019), forced with surface mass balance (SMB) calculated with the Community Earth System Model version 2 (CESM2, Danabasoglu et al. 2020). We use different forcing climatologies from a coupled CESM2/CISM2 simulation under high greenhouse gas forcing (Muntjewerf et al. 2020), where each climatology corresponds to a different global warming level in the range of 1-8.5 K above the pre-industrial climate. The SMB, which is calculated in CESM2 using an advanced energy balance scheme at multiple elevation classes (Muntjewerf et al. 2020), is downscaled during runtime to CISM2, thus allowing to account for the surface elevation feedback. In all the simulations the forcing is cycled until the ice sheet is fully deglaciated or has reached a new equilibrium. In a first set of simulations, we find that for a warming level higher than 5.2 K above pre-industrial the ice sheet will disappear, with the timing ranging between 2000 (+8.5 K) and 6000 years (+5.2 K). At a warming level of 2.8 K above pre-industrial, the ice loss does not exceed 2 m SLE, and most of the retreat occurs in the first 10,000 years in the south-west and central-west basins. In contrast, with a higher warming level of 3.6 K above pre-industrial as much as 7 m SLE of ice are loss in 20,000 years, with primary contributions from the western, northern and north-eastern basins. We will conclude by showing preliminary results from a second set of simulations focusing on the 2.8-3.6 K warming above pre-industrial interval.</p>


Author(s):  
Henrik Højmark Thomsen ◽  
Niels Reeh ◽  
Ole B. Olesen ◽  
Carl Egede Bøggilde ◽  
Wolfgang Starzer ◽  
...  

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Højmark Thomsen, H., Reeh, N., Olesen, O. B., Egede Bøggilde, C., Starzer, W., Weidick, A., & Higgins, A. K. (1997). The Nioghalvfjerdsfjorden glacier project, North-East Greenland: a study of ice sheet response to climatic change. Geology of Greenland Survey Bulletin, 176, 95-103. https://doi.org/10.34194/ggub.v176.5073 _______________ Glaciological research was initiated in 1996 on the floating glacier tongue filling Nioghalvfjerdsfjorden in NorthEast Greenland (Fig. 1), with the aim of acquiring a better understanding of the response of the Greenland ice sheet (Inland Ice) to changing climate, and the implications for future sea level. The research is part of a three year project (1996–98) to advance research into the basic processes that contribute to changes in the ocean volume with a changing climate. Five nations are participants in the project, which is supported by the European Community (EC) Environment and Climate Programme. The Geological Survey of Denmark and Greenland (GEUS) and the Danish Polar Center are the Danish partners in the project, both with integrated research themes concentrated on and around Nioghalvfjerdsfjorden.


Author(s):  
Patrick J. Applegate ◽  
K. Keller

Engineering the climate through albedo modification (AM) could slow, but probably would not stop, melting of the Greenland Ice Sheet. Albedo modification is a technology that could reduce surface air temperatures through putting reflective particles into the upper atmosphere. AM has never been tested, but it might reduce surface air temperatures faster and more cheaply than reducing greenhouse gas emissions. Some scientists claim that AM would also prevent or reverse sea-level rise. But, are these claims true? The Greenland Ice Sheet will melt faster at higher temperatures, adding to sea-level rise. However, it's not clear that reducing temperatures through AM will stop or reverse sea-level rise due to Greenland Ice Sheet melting. We used a computer model of the Greenland Ice Sheet to examine its contributions to future sea level rise, with and without AM. Our results show that AM would probably reduce the rate of sea-level rise from the Greenland Ice Sheet. However, sea-level rise would likely continue even with AM, and the ice sheet would not regrow quickly. Albedo modification might buy time to prepare for sea-level rise, but problems could arise if policymakers assume that AM will stop sea-level rise completely.


1990 ◽  
Vol 36 (123) ◽  
pp. 217-221 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole B. Olesen

AbstractDaily ice ablation on two outlet glaciers from the Greenland ice sheet, Nordbogletscher (1979–83) and Qamanârssûp sermia (1980–86), is related to air temperature by a linear regression equation. Analysis of this ablation-temperature equation with the help of a simple energy-balance model shows that sensible-heat flux has the greatest temperature response and accounts for about one-half of the temperature response of ablation. Net radiation accounts for about one-quarter of the temperature response of ablation, and latent-heat flux and errors account for the remainder. The temperature response of sensible-heat flux at QQamanârssûp sermia is greater than at Nordbogletscher mainly due to higher average wind speeds. The association of high winds with high temperatures during Föhn events further increases sensible-heat flux. The energy-balance model shows that ablation from a snow surface is only about half that from an ice surface at the same air temperature.


Author(s):  
Libo Wang ◽  
Martin Sharp ◽  
Benoit Rivard ◽  
Konrad Steffen

Sign in / Sign up

Export Citation Format

Share Document