Glacial geology and Quaternary marine stratigraphy of the Robeson Channel area, northeastern Ellesmere Island, Northwest Territories

1986 ◽  
Vol 23 (7) ◽  
pp. 1001-1012 ◽  
Author(s):  
Michael J. Retelle
Keyword(s):  
Greenland Ice Sheet ◽  
Free Fraction ◽  
High Arctic ◽  
Ellesmere Island ◽  
Major Advance ◽  
Total Acid ◽  
Radiocarbon Dates ◽  
The Holocene ◽  
Acid Hydrolysate ◽  
Field Area

Glacial and marine deposits associated with two phases of glaciation are exposed along a 60 km corridor on Ellesmere Island that borders Robeson Channel. The oldest sediments, tentatively dated at ≥ 70 000 BP, were deposited during a major advance of the northwest Greenland ice sheet across Robeson Channel. During subsequent retreat of this ice mass, glaciomarine sediments containing a High Arctic macro- and microfauna were deposited in the isostatic downwarp on Ellesmere Island. This marine unit was radiocarbon dated at 31 300 ± 900 and > 32 000 BP; mean aIle/Ile ratios are 0.218 ± 0.03 for the free fraction and 0.063 ± 0.011 for the total acid hydrolysate.The last ice advance (late Wisconsin – early Holocene) did not extend into the field area from either interior Ellesmere Island or northwest Greenland. The ice-marginal sea transgressed to the marine limit (~116 m) and overlapped the deposits of the previous maximum Greenland advance. Local plateau ice caps did, however, spill over into one major valley and delayed the establishment of the marine limit in this location. Radiocarbon dates on the Holocene marine limit shorelines indicate initial emergence between 8000 and 8600 BP. A mean aIle/Ile ratio of 0.037 was found for the total acid hydrolysate; aIle was undetectable in the free fraction of the Holocene shells.The Holocene and pre-Holocene glacial and marine chronologies in the Robeson Channel area are similar to chronologies demonstrated from other locations in Arctic regions. Tentative correlations based upon aminostratigraphy suggest that the field area has remained, for the most part, ice free since at least 70 000 BP.

The last glaciation and sea level history of Fosheim Peninsula, Ellesmere Island, Canadian High Arctic

1996 ◽  
Vol 33 (7) ◽  
pp. 1075-1086 ◽  
Author(s):  
Trevor Bell
Keyword(s):  
High Arctic ◽  
Radiocarbon Dates ◽  
The Holocene ◽  
Ice Caps ◽  
Marine Deposits ◽  
Last Glaciation ◽  
Maximum Elevation ◽  
Glacier Runoff ◽  
History Of ◽  
Ice Conditions

The last glaciation of Fosheim Peninsula is reconstructed on the basis of landform and sediment mapping and associated radiocarbon dates. Ice growth involved the expansion of cirque glaciers and accumulation on upland surfaces that are now ice free. Limited ice buildup, despite lowering of the paleoglaciation level by 700–800 m, is attributed to the hyperaridity of the region during glacial conditions. Marine deposits in formerly submerged basins beyond the ice margins are interpreted to represent (i) sedimentation caused by local ice buildup and marine transgression by 10.6 ka BP, (ii) increased ablation and glacier runoff [Formula: see text]9.5 ka BP, and (iii) marine regression during the Holocene. Holocene marine limit reaches a maximum elevation of approximately 150 m asl along northern Eureka Sound and Greely Fiord and descends southeastwards to 139–142 m asl near the Sawtooth Mountains. A synchronous marine limit is implied where the last ice limit was inland of the sea. The magnitude and pattern of Holocene emergence cannot be fully explained by the glacioisostatic effects of the small ice load during the last glaciation of the region. Deglaciation of the peninsula was underway by 9.5 ka BP; however, local ice caps may have persisted through the wannest period of the Holocene until 6–5 ka BP. This was likely a function of reduced sea ice conditions and increased moisture availability which benefited low-lying coastal icefields, but had negligible effect on interior highland ice caps.

The glacial geology of northeastern Ellesmere Island, N.W.T., Canada

1978 ◽  
Vol 15 (4) ◽  
pp. 603-617 ◽  
Author(s):  
John England
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ellesmere Island ◽  
Glacial Geology ◽  
Radiocarbon Dates ◽  
Previous Evidence ◽  
Marine Deposits ◽  
Last Glaciation ◽  
Distal Side ◽  
Stratigraphic Boundary

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.

The last glaciation of Marvin Peninsula, northern Ellesmere Island, High Arctic, Canada

1989 ◽  
Vol 26 (12) ◽  
pp. 2578-2590 ◽  
Author(s):  
Donald S. Lemmen
Keyword(s):  
High Arctic ◽  
Ellesmere Island ◽  
North Coast ◽  
Radiocarbon Dates ◽  
The North ◽  
Last Glaciation ◽  
Ice Retreat ◽  
Late Wisconsinan ◽  
Glaciomarine Sediments ◽  
North And South

The limit of the last glaciation on Marvin Peninsula, northernmost Ellesmere Island, is recorded by extensive ice-marginal landforms and early Holocene glaciomarine sediments. While glaciers occupied most valleys on the peninsula, other areas remained ice free, as did most of the adjacent fiords. Beyond the ice limit, sparse erratics and degraded meltwater channels within weathered bedrock are evidence of older, more extensive glaciation(s). Shorelines and marine shells 50 m above the limit of the Holocene sea along the north coast relate to these older glacial events.Thirty-four new radiocarbon dates provide a chronology of ice buildup and retreat. Glaciers reached their limit after 23 ka, and locally as late as 11 ka. This was achieved by both expansion of existing glaciers and accumulation on plateau and lowland sites, which are presently ice free. Late Wisconsinan climate was characterized by cold and extreme aridity. Five dates ranging from 11 to 31 ka BP on subfossil bryophytes suggest that ice-free areas were biologically productive throughout the last glaciation. Ice retreat and postglacial emergence had begun by 9.5 ka and was associated with a marked climatic amelioration. The deglacial chronology confirms a pronounced disparity in the timing of ice retreat on the north and south sides of the Grant Land Mountains.

scholarly journals Glaciers and ice caps through the Holocene: A pan–Arctic synthesis of lake–based reconstructions

2021 ◽  
Author(s):  
Laura J. Larocca ◽  
Yarrow Axford
Keyword(s):  
Greenland Ice Sheet ◽  
High Arctic ◽  
Early Holocene ◽  
The Arctic ◽  
Boreal Summer ◽  
Russian Arctic ◽  
The Holocene ◽  
Ice Caps ◽  
Summer Insolation ◽  
Arctic Regions

Abstract. The recent retreat of nearly all glaciers and ice caps (GICs) located in Arctic regions is one of the most clear and visible signs of ongoing climate change. This paper synthesizes published records of Holocene GIC fluctuations from lake archives, placing their recent retreat into a longer–term context. Our compilation includes sixty–six lake–based GIC records (plus one non–lake–based record from the Russian Arctic) from seven Arctic regions: Alaska; the archipelagos of the eastern Canadian Arctic; GICs peripheral to the Greenland Ice Sheet; Iceland; the Scandinavian peninsula; Svalbard; and the Russian high Arctic. For each region, and for the full Arctic, we summarize evidence for when GICs were smaller than today or absent altogether, indicating warmer than present summers, and evidence for when GICs regrew in lake catchments, indicating summer cooling. Consistent with orbitally driven high boreal summer insolation in the early Holocene, the pan–Arctic compilation suggests that the majority (50 % or more) of studied GICs were smaller than present or absent by ~10 ka. The regional compilations suggest even earlier GIC loss, and thus warmth, in the Russian Arctic and in Svalbard. We find the highest percentage (>90 %) of Arctic GICs smaller than present or absent in the middle Holocene ~7–6 ka, probably reflecting more spatially ubiquitous and consistent summer warmth during this period than in the early Holocene. Following this interval of widespread warmth, our compilation shows that GICs across the Arctic began to regrow, and summers began to cool by ~6 ka. Together, the pan–Arctic records also suggest two periods of enhanced GIC growth in the mid–to–late Holocene, from ~4.5–3 ka and after ~2 ka. The regional records show substantial variability in the timing of GIC regrowth within and between regions, suggesting that the Arctic did not cool synchronously despite the smooth and hemispherically symmetric decline in Northern Hemisphere summer insolation. In agreement with other studies, this implies a combined response to glacier–specific characteristics such as topography, and to other climatic forcings and feedback mechanisms, perhaps driving periods of increased regional cooling. Today, the direction of orbital forcing continues to favor GIC expansion, however, the rapid retreat of nearly all Arctic GICs underscores the current dominance of anthropogenic forcing on GIC mass balance. Our review finds that in the first half of the Holocene, most of the Arctic’s small GICs became significantly reduced or melted away completely in response to summer temperatures that, on average, were only moderately warmer than today. In comparison, future projections of temperature change in the Arctic far exceed estimated early Holocene values in most locations, portending the eventual loss of most of the Arctic’s small GICs.

scholarly journals Postglacial Isobases from Northern Ellesmere Island and Greenland: New Data

2007 ◽  
Vol 40 (3) ◽  
pp. 299-305 ◽  
Author(s):  
John England ◽  
Jan Bednarski
Keyword(s):  
Response Times ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ellesmere Island ◽  
Radiocarbon Dates ◽  
Sea Levels ◽  
Ice Caps ◽  
History Of ◽  
Considerable Range

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.

Geomorphic and sedimentary signatures of early Holocene deglaciation in High Arctic fiords, Ellesmere Island, Canada: implications for deglacial ice dynamics and thermal regime

1998 ◽  
Vol 35 (4) ◽  
pp. 437-452 ◽  
Author(s):  
Colm Ó Cofaigh
Keyword(s):  
Thermal Regime ◽  
High Arctic ◽  
Ellesmere Island ◽  
Early Holocene ◽  
Ice Dynamics ◽  
Discrete Location ◽  
Radiocarbon Dates ◽  
Fine Grained ◽  
Subsequent Stabilization

Integrated studies of glacial geomorphology, sedimentology, marine-limit elevations, and radiocarbon dating in two adjacent fiords on southwestern Ellesmere Island indicate that early Holocene regional deglaciation was characterized by a two-step retreat pattern, where initial rapid breakup of marine-based ice preceded slower, terrestrial retreat. These data also indicate interfiord variations in early Holocene deglacial thermal regime, and illustrate the role of fiord topography as a control on glacier retreat. In Starfish Bay, deglacial landform-sediment associations are preferentially located at fiord-side topographic irregularities, and record ice-proximal glaciomarine sedimentation during stillstands at pinning points. Abundant fine-grained subaquatic outwash indicates that the retreating trunk glacier was characterized by a warm-based thermal regime. The discrete location of these deposits and associated radiocarbon dates suggest rapid early Holocene deglaciation of the outer and middle fiord, interrupted by brief stillstands at pinning points, and subsequent stabilization and slower retreat in the inner fiord. Similar rapid early Holocene deglaciation occurred in Blind Fiord. However, the dominance of lateral meltwater channels and lack of fine-grained subaquatic outwash in this fiord suggest that trunk ice was predominantly cold-based during retreat. Initial rapid deglaciation was succeeded by stabilization and slower, terrestrial retreat when the trunk glacier reached the inner fiord. A prominent belt of glaciogenic landforms at the heads of both fiords is inferred to mark this stabilization.

Do Greenland Ice Cores Reflect NW European Interglacial Climate Variations?

1995 ◽  
Vol 43 (2) ◽  
pp. 125-132 ◽  
Author(s):  
Eiliv Larsen ◽  
Hans Petter Sejrup ◽  
Sigfus J. Johnsen ◽  
Karen Luise Knudsen
Keyword(s):  
Western Europe ◽  
Ice Core ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
High Amplitude ◽  
Atlantic Water ◽  
Polar Front ◽  
Norwegian Sea ◽  
The Holocene ◽  
Climatic Evolution

AbstractThe climatic evolution during the Eemian and the Holocene in western Europe is compared with the sea-surface conditions in the Norwegian Sea and with the oxygen-isotope-derived paleotemperature signal in the GRIP and Renland ice cores from Greenland. The records show a warm phase (ca. 3000 yr long) early in the Eemian (substage 5e). This suggests that the Greenland ice sheet, in general, recorded the climate in the region during this time. Rapid fluctuations during late stage 6 and late substage 5e in the GRIP ice core apparently are not recorded in the climatic proxies from western Europe and the Norwegian Sea. This may be due to low resolution in the terrestrial and marine records and/or long response time of the biotic changes. The early Holocene climatic optimum recorded in the terrestrial and marine records in the Norwegian Sea-NW European region is not found in the Summit (GRIP and GISP2) ice cores. However, this warm phase is recorded in the Renland ice core. Due to the proximity of Renland to the Norwegian Sea, this area is probably more influenced by changes in polar front positions which may partly explain this discrepancy. A reduction in the elevation at Summit during the Holocene may, however, be just as important. The high-amplitude shifts during substage 5e in the GRIP core could be due to Atlantic water oscillating closer to, and also reaching, the coast of East Greenland. During the Holocene, Atlantic water was generally located farther east in the Norwegian Sea than during the Eemian.

Limnology of high arctic ponds (Cape Herschel, Ellesmere Island, N. W. T.)

1994 ◽  
Vol 131 (4) ◽  
pp. 401-434
Author(s):  
Marianne S. V. Douglas ◽  
John P. Smol
Keyword(s):  
High Arctic ◽  
Ellesmere Island ◽  
Arctic Ponds

scholarly journals The Holocene thermal maximum in the Nordic Seas: the impact of Greenland Ice Sheet melt and other forcings in a coupled atmosphere–sea-ice–ocean model

2013 ◽  
Vol 9 (4) ◽  
pp. 1629-1643 ◽  
Author(s):  
M. Blaschek ◽  
H. Renssen
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Early Holocene ◽  
Surface Cooling ◽  
Holocene Climate ◽  
Nordic Seas ◽  
The Holocene ◽  
Holocene Thermal Maximum ◽  
Thermal Maximum ◽  
The Impact

Abstract. The relatively warm early Holocene climate in the Nordic Seas, known as the Holocene thermal maximum (HTM), is often associated with an orbitally forced summer insolation maximum at 10 ka BP. The spatial and temporal response recorded in proxy data in the North Atlantic and the Nordic Seas reveals a complex interaction of mechanisms active in the HTM. Previous studies have investigated the impact of the Laurentide Ice Sheet (LIS), as a remnant from the previous glacial period, altering climate conditions with a continuous supply of melt water to the Labrador Sea and adjacent seas and with a downwind cooling effect from the remnant LIS. In our present work we extend this approach by investigating the impact of the Greenland Ice Sheet (GIS) on the early Holocene climate and the HTM. Reconstructions suggest melt rates of 13 mSv for 9 ka BP, which result in our model in an ocean surface cooling of up to 2 K near Greenland. Reconstructed summer SST gradients agree best with our simulation including GIS melt, confirming that the impact of the early Holocene GIS is crucial for understanding the HTM characteristics in the Nordic Seas area. This implies that modern and near-future GIS melt can be expected to play an active role in the climate system in the centuries to come.

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