Holocene history of the Greenland Ice-Sheet margin in Northern Nunatarssuaq, Northwest Greenland

arktos ◽  
2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Lauren B. Farnsworth ◽  
Meredith A. Kelly ◽  
Gordon R. M. Bromley ◽  
Yarrow Axford ◽  
Erich C. Osterberg ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
History Of

scholarly journals Glacial history of Inglefield Land, north Greenland from combined in-situ <sup>10</sup>Be and <sup>14</sup>C exposure dating

2020 ◽  
Author(s):  
Anne Sofie Søndergaard ◽  
Nicolaj Krog Larsen ◽  
Olivia Steinemann ◽  
Jesper Olsen ◽  
Svend Funder ◽  
...  
Keyword(s):  
Climate Changes ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Age ◽  
Glacial History ◽  
Holocene Climate ◽  
Exposure Dating ◽  
History Of ◽  
North Greenland

Abstract. Exposing the sensitivity of the Greenland Ice Sheet (GrIS) to Holocene climate changes is a key prerequisite for understanding the future response of the ice sheet to global warming. In this study, we present new information on the Holocene glacial history of the GrIS in Inglefield Land, north Greenland. We use 10Be and in-situ 14C exposure dating to constrain the timing of deglaciation in the area and radiocarbon dating of reworked molluscs and wood fragments to constrain when the ice sheet retreated behind its present-day extent. The 10Be ages are scattered ranging from c. 92.7 to 6.8 ka whereas the in-situ 14C ages range from c. 14.2 to 6.7 ka. Almost half of the apparent 10Be ages predate the Last Glacial Maximum and up to 89 % are to some degree affected by nuclide inheritance. Based on the few reliable 10Be ages, the in-situ 14C ages and existing radiocarbon ages from Inglefield Land, we find that the deglaciation along the coast commenced c. 8.6–8.3 cal. ka BP in the western part and c. 7.9 ka in the central part, following the opening of Nares Strait and arrival of warm waters. The ice margin reached its present-day position c. 8.2 ka at the Humboldt Glacier and c. 6.7 ka in the central part of Inglefield Land. Radiocarbon ages of reworked molluscs and wood fragments show that the ice margin was behind its present-day extent from c. 5.8 to 0.5 cal. ka BP. After 0.5 cal. ka BP, the ice advanced towards its Little Ice Age position. Our results emphasize that the slowly eroding and possibly cold-based ice in north Greenland makes it difficult to constrain the deglaciation history based on 10Be ages alone unless it is paired with in-situ 14C ages. Further, combining our findings with those of recently published studies reveals distinct differences between deglaciation patterns of northwest and north Greenland. Deglaciation of the land areas in northwest Greenland occurred earlier than in north Greenland and periods of restricted ice extent were longer, spanning middle and late Holocene. Overall, this highlights past ice sheet sensitivity towards Holocene climate changes in an area where little information was available just a few years ago.

scholarly journals Ice-Penetrating Radar Reveals Age of Greenland Ice Sheet Layers

Eos ◽  
2015 ◽  
Vol 96 ◽  
Author(s):  
Terri Cook
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Radar Data ◽  
Comprehensive Analysis ◽  
History Of ◽  
Insight Into

First comprehensive analysis of deep radar data gives insight into the dynamics and history of the Greenland Ice Sheet.

Greenland Ice Sheet History Since the Last Glaciation

1974 ◽  
Vol 4 (4) ◽  
pp. 429-440 ◽  
Author(s):  
Norman W. Ten Brink ◽  
Anker Weidick
Keyword(s):  
Average Rate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
Large Area ◽  
West Greenland ◽  
Last Glaciation ◽  
History Of ◽  
Inland Ice

The position of the Inland Ice margin during the late Wisconsin-Würm glaciation (ca. 15,000 yr BP) is probably marked by offshore banks (submarine moraines?) in the Davis Strait. The history of the Inland Ice since the late Wisconsin-Würm can be divided into four principal phases: (1) Relatively slow retreat from the offshore banks occurred at an average rate of approximately 1 km/100 yr until ca. 10,000 yr BP (Younger Dryas?) when the Taserqat moraine system was formed by a readvance. (2) At ca. 9500 yr BP, the rate of retreat increased markedly to about 3 km/100 yr, and although nearly 100 km of retreat occurred by ca. 6500 yr BP, it was punctuated by frequent regional reexpansions of the Inland Ice that formed extensive moraine systems at ca. 8800-8700 yr BP (Avatdleq-Sarfartôq moraines), 8400-8100 yr BP (Angujârtorfik-Fjord moraines), 7300 yr BP (Umîvît moraines), and 7200-6500 yr BP (Keglen-Mt, Keglen moraines). (3) Between 6500 and 700 yr BP, discontinous ice-margin deposits and ice-disintegration features were formed during retreat, which may have continued until the ice margin was near or behind its present position by ca. 6000 yr BP. Most of the discontinuous ice-margin deposits occur within 5–10 km of the present ice margin, and may have been formed by two main phases of readvance at ca. 4800-4000 yr BP and 2500-2000 yr BP. (4) Since a readvance at ca. 700 yr BP, the Inland Ice margin has undergone several minor retreats and readvances resulting in deposition of numerous closely spaced moraines within about 3 km of the present ice margin. The young moraines are difficult to correlate regionally, but several individual moraines have the following approximate ages: A.D. 1650, 1750, and 1880–1920.Inland Ice fluctuations in West Greenland were very closely paralleled by Holocene glacial events in East Greenland and the eastern Canadian Arctic. Such similarity of glacier behavior over a large area strongly suggests that widespread climatic change was the direct cause of Holocene glacial fluctuations. Moreover, historical advances of the Inland Ice margin followed slight temperature decreases by no more than a few decades, and 18O data from Greenland ice cores show that slight temperature decreases occurred frequently throughout the Holocene. Therefore, we conclude that construction of the major Holocene moraine systems in West Greenland was caused by slight temperature decreases, which decreased rates of ablation and thereby produced practically immediate advances of the ice sheet margin, but did not necessarily affect the long-term equilibrium of the ice sheet.

Unearthing the forgotten record of glacier change in southeast Greenland

2020 ◽  
Author(s):  
Michael Cooper ◽  
Paulina Lewinska ◽  
Julian Dowdeswell ◽  
Edwin Hancock ◽  
William Smith ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Quantitative Information ◽  
Glacier Change ◽  
Regular Time ◽  
History Of ◽  
Long Term Trends ◽  
Surface Profiles ◽  
Volume Estimates

&lt;p&gt;Prior to the satellite era (pre-1970s) knowledge of long-term glacier change is sparse. Although some glacier-wide mass balance datasets are available, few records extend beyond twenty years in length, or indeed, start prior to the 1980s; as such, identifying long-term trends between glacier change and global temperatures is difficult. As a result, extending the record of glacier change will not only help to identify such trends, but may also facilitate more robust understanding of future glacier response under a perturbed and varying climate.&lt;/p&gt;&lt;p&gt;Since the &amp;#8216;heroic age of Arctic (and Antarctic) exploration&amp;#8217;, many photographs of polar environments have been captured and stored for historic interest. These photographs, depicting images of past glaciers and ice sheet margins, have, as of yet, untapped potential to provide important insights into past glacier extent, and long-term behaviour.&lt;/p&gt;&lt;p&gt;Using computer-vision methodologies, we present a unique record of georeferenced 3-D elevation models using declassified aerial imagery dating from the 1930s&amp;#8212;1980s at quasi-regular time steps. This study focusses upon two sections (ca. 190 km total length) of the southeast margin of the Greenland Ice Sheet (in the vicinity of Kangerlussuaq Glacier), capturing the history of both land- and marine-terminating outlet glaciers, and local glaciers. We examine quantitative information extracted from these reconstructions, allowing us to &amp;#8216;back extend&amp;#8217; the record of glacial change in this region, by measuring changes in glacial extent, surface profiles and height (elevation), and calculating volume estimates.&lt;/p&gt;

Glaciological investigations on ice-sheet response in South Greenland

2002 ◽  
pp. 150-156 ◽  
Author(s):  
Christoph Mayer ◽  
Carl E. Bøggild ◽  
Steffen Podlech ◽  
Ole B. Olesen ◽  
Andreas P. Ahlstrøm ◽  
...  
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Global Climate ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Field Work ◽  
Scientific Debate ◽  
History Of ◽  
Inland Ice

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Mayer, C., Bøggild, C. E., Podlech, S., Olesen, O. B., Ahlstrøm, A. P., & Krabill, W. (2002). Glaciological investigations on ice-sheet response in South Greenland. Geology of Greenland Survey Bulletin, 191, 150-156. https://doi.org/10.34194/ggub.v191.5143 _______________ The reaction of the world’s large ice sheets to global climate change is still in the focus of scientific debate. Recent investigations have shown pronounced thinning in the southern part of the Greenland ice sheet (Inland Ice). In order to investigate the cause of the observed thinning and to judge the sensitivity of this part of the ice sheet a combined field work, remote sensing and modelling project was designed. A glaciological transect was established in May 2001 on one of the main outlet glaciers in South Greenland (Fig. 1), and the first data are now available. In addition, the history of the glacier variations during the last 40 years has been reconstructed.

scholarly journals Surface mass-balance changes of the Greenland ice sheetc since 1866

2009 ◽  
Vol 50 (50) ◽  
pp. 178-184 ◽  
Author(s):  
L.M. Wake ◽  
P. Huybrechts ◽  
J.E. Box ◽  
E. Hanna ◽  
I. Janssens ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Surface Mass Balance ◽  
Retention Model ◽  
Surface Mass ◽  
The Past ◽  
Temperature And Precipitation ◽  
Elevation Changes ◽  
History Of

AbstractMass loss from the Greenland ice sheet over the past decade has caused the impression that the ice sheet has been behaving anomalously to the warming of the 1990s. We have reconstructed the recent (1866–2005) surface mass-balance (SMB) history of the Greenland ice sheet on a 5 × 5 km grid using a runoff-retention model based on the positive degree-day method. The model is forced with new datasets of temperature and precipitation patterns dating back to 1866.We use an innovative method to account for the influence of year-on-year surface elevation changes on SMB estimates and have found this effect to be minor. All SMB estimates are made relative to the 1961–90 average SMB and we compare annual SMB estimates from the period 1995–2005 to a similar period in the past (1923–33) where SMB was comparable, and conclude that the present-day changes are not exceptional within the last 140 years. Peripheral thinning has dominated the SMB response during the past decade, as in 1923–33, but we also show that thinning was not restricted to the margins during this earlier period.

scholarly journals Early Holocene history of the west Greenland Ice Sheet and the GH-8.2 event

2006 ◽  
Vol 25 (9-10) ◽  
pp. 904-922 ◽  
Author(s):  
A.J. Long ◽  
D.H. Roberts ◽  
S. Dawson
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Early Holocene ◽  
The West ◽  
West Greenland ◽  
History Of

scholarly journals The timing of fjord formation and early glaciations in North and Northeast Greenland

2020 ◽  
Author(s):  
Vivi Kathrine Pedersen ◽  
Nicolaj Krog Larsen ◽  
David Lundbek Egholm
Keyword(s):  
Late Miocene ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Early History ◽  
Early Pleistocene ◽  
Late Pliocene ◽  
Isostatic Uplift ◽  
History Of ◽  
Erosional Unloading ◽  
North Greenland

&lt;p&gt;The timing and extent of early glaciations in Greenland, and their co-evolution with the underlying landscape remain elusive. In this study, we explore the timing of fjord erosion in Northeast and North Greenland between Scoresby Sund (70&amp;#176;N) and Independence Fjord (82&amp;#176;N). By determining the timing of fjord formation, we can improve our understanding of the early history of the Greenland Ice Sheet in these regions.&lt;/p&gt;&lt;p&gt;We use the concept of geophysical relief to estimate fjord erosion and calculate the subsequent flexural isostatic response to erosional unloading. The timing of erosion and isostatic uplift is constrained by marine sediments of late Pliocene-early Pleistocene age that are now exposed on land between ~24 and 230 m a.s.l.&lt;/p&gt;&lt;p&gt;We find that the northern Independence Fjord system must have formed by glacial erosion at average rates of ~0.5-1 mm/yr since ~2.5 Ma, in order to explain the current elevation of the marine Kap K&amp;#248;benhavn Formation by erosion-induced isostatic uplift. In contrast, fjord formation in the outer parts of southward Scoresby Sund commenced before the Pleistocene, most likely in late Miocene, and continued throughout the Pleistocene by fjord formation progressing inland. Our results suggest that the inception of the Greenland Ice Sheet began in the central parts of Northeast Greenland before the Pleistocene and spread to North Greenland only at the onset of the Pleistocene. &amp;#160;&lt;/p&gt;

scholarly journals New programme for climate monitoring at Camp Century, Greenland

2017 ◽  
pp. 57-60 ◽  
Author(s):  
William Colgan ◽  
Signe B. Andersen ◽  
Dirk Van As ◽  
Jason E. Box ◽  
Søren Gregersen
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Us Army ◽  
Future Goals ◽  
Climate Monitoring ◽  
The Us ◽  
History Of ◽  
The Government

Camp Century was a military base constructed by the US Army Corps of Engineers (USACE) in 1959 in the nearsurface layers of the Greenland ice sheet at 77.13°N and 61.03°W and 1910 metres above sea level (Clark 1965). The c. 55 ha base housed between 85 and 200 soldiers and was continuously occupied until 1964 (Fig.1). Camp Century primarily served as an experimental facility for the USACE to test ice-sheet construction concepts. Recent Danish scholarship has documented the political and military history of Camp Century in substantial detail (Petersen 2007; Nielsen & Nielsen 2016). To summarise, Project Iceworm, the US Army ambition to deploy offensive missiles within the ice sheet, was never realised. After three years of seasonal operation, Camp Century was finally abandoned with minimal decommissioning in 1967. The Government of Denmark has now established a GEUS-led programme for long-term climate monitoring, as well as one-time waste mapping, at Camp Century. Here, we briefly review the historical scientific activities at Camp Century and introduce the future goals of the Camp Century Climate Monitoring Programme. Finally, we discuss the challenges and outlook of climate monitoring and waste mapping at the former military site.

scholarly journals Glacial history of Inglefield Land, north Greenland from combined in situ <sup>10</sup>Be and <sup>14</sup>C exposure dating

2020 ◽  
Vol 16 (5) ◽  
pp. 1999-2015
Author(s):  
Anne Sofie Søndergaard ◽  
Nicolaj Krog Larsen ◽  
Olivia Steinemann ◽  
Jesper Olsen ◽  
Svend Funder ◽  
...  
Keyword(s):  
Climate Changes ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Age ◽  
Glacial History ◽  
Holocene Climate ◽  
Exposure Dating ◽  
History Of ◽  
North Greenland

Abstract. Determining the sensitivity of the Greenland Ice Sheet (GrIS) to Holocene climate changes is a key prerequisite for understanding the future response of the ice sheet to global warming. In this study, we present new information on the Holocene glacial history of the GrIS in Inglefield Land, north Greenland. We use 10Be and in situ 14C exposure dating to constrain the timing of deglaciation in the area and radiocarbon dating of reworked molluscs and wood fragments to constrain when the ice sheet retreated behind its present-day extent. The 10Be ages are scattered ranging from ca. 92.7 to 6.8 ka, whereas the in situ 14C ages range from ca. 14.2 to 6.7 ka. Almost half of the apparent 10Be ages predate the Last Glacial Maximum and up to 89 % are to some degree affected by nuclide inheritance. Based on the few reliable 10Be ages, the in situ 14C ages and existing radiocarbon ages from Inglefield Land, we find that the deglaciation along the coast commenced at ca. 8.6–8.3 ka cal BP in the western part and ca. 7.9 ka in the central part, following the opening of Nares Strait and arrival of warm waters. The ice margin reached its present-day position at ca. 8.2 ka at the Humboldt Glacier and ca. 6.7 ka in the central part of Inglefield Land. Radiocarbon ages of reworked molluscs and wood fragments show that the ice margin was behind its present-day extent from ca. 5.8 to 0.5 ka cal BP. After 0.5 ka cal BP, the ice advanced towards its Little Ice Age position. Our results emphasize that the slowly eroding and possibly cold-based ice in north Greenland makes it difficult to constrain the deglaciation history based on 10Be ages alone unless they are paired with in situ 14C ages. Further, combining our findings with those of recently published studies reveals distinct differences between deglaciation patterns of northwest and north Greenland. Deglaciation of the land areas in northwest Greenland occurred earlier than in north Greenland, and periods of restricted ice extent were longer, spanning the Middle and Late Holocene. Overall, this highlights past ice sheet sensitivity to Holocene climate changes in an area where little information was available just a few years ago.

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