The late Quaternary history of Hall Land, northwest Greenland

1985 ◽  
Vol 22 (10) ◽  
pp. 1394-1408 ◽  
Author(s):  
John England
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Greenland Ice Sheet ◽  
Ellesmere Island ◽  
Relative Sea Level ◽  
Ice Shelves ◽  
Central Plain ◽  
Nares Strait ◽  
Initial Penetration ◽  
History Of

The last ice limit on Hall Land, northwest Greenland, is marked by the Newman and Petermann moraines, which were deposited 40–60 km beyond the present ice margins in Newman Bay and Petermann Fiord, respectively. These moraines flank the eastern and western coasts of Hall Land but do not extend into its intervening central plain. As a result of glacioisostatic depression at this time, a full glacial sea transgressed the entire central plain via a narrow estuary located between the Newman Moraine and the northern plateau of Hall Land. The limit of this full glacial sea is isostatically tilted from 116 m asl on the adjacent coast of Ellesmere Island to 150 m asl on the southwest extremity of the central plain, where it reaches its apex. Pervasive marine silts cover the central plain and laterally thicken towards the Newman and Petermann moraines. Because of the height of the full glacial sea, these moraines were deposited in a submarine environment and mark the grounded margins of ice shelves floating in Hall Basin and Newman Bay.Twenty-seven samples of marine pelecypods from the proximal and distal sides of these moraines were 14C dated. Distal to the moraines the limit of the full glacial sea is dated by in situ shells that range from 8200 to > 33 000 BP. During this interval relative sea level remained stable and the ice load was apparently in isostatic equilibrium. Initial emergence (unloading) throughout the full glacial sea (~8200 BP) coincides with the initial penetration of the sea inside the Newman Moraine dated at 7965 BP and inside the Petermann Moraine at 8280 and 8295 BP.This research concludes that (1) there was no Nares Strait ice ridge during the last glaciation, (2) ice retreat of only 40–60 km can cause 140–150 m of emergence, and (3) the deglaciation of northwest Greenland began at 8000 and not 10 000 BP. This research confirms that the relative sea-level curves from the adjacent coast of Ellesmere Island were isostatically dominated by the Greenland Ice Sheet.

The late Quaternary history of Greely Fiord and its tributaries, west-central Ellesmere Island

1990 ◽  
Vol 27 (2) ◽  
pp. 255-270 ◽  
Author(s):  
John England
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Sensu Stricto ◽  
Ellesmere Island ◽  
Relative Sea Level ◽  
Ice Caps ◽  
Last Glaciation ◽  
West Central ◽  
Grounding Line ◽  
Minimum Age

Moraines and meltwater channels mark the limit of the last glaciation that interfingered with the sea around the perimeter of Greely Fiord and its tributaries. The extent of this ice advance was dictated predominantly by its proximity to the sea. Consequently, the large tidewater glaciers at the fiord heads today were so constrained by calving that they advanced only 5–10 km. Similarly, grounding-line deposits from widespread plateau ice caps also terminate just below marine limit. The most extensive outlet glaciers, which advanced 20–35 km beyond present margins, are simply those that had access to the most extensive terrain above marine limit, i.e., the northwest margin of the Agassiz Ice Cap.Forty-one new 14C dates are presented. The onset of the last ice advance must predate marine shells collected from sediments overlying a former grounding line when sea level was 122 m higher than present. At this site, the lowermost shells collected from glaciomarine silts dated 38 070 ± 410 BP, whereas a surface sample 13 m above them dated 22 900 ± 190 BP. Although both dates may be minimum estimates, they are nonetheless associated with an ice margin that retreated only a few kilometres by 7850 BP, suggesting the maintenance of the glacioisostatic loading (and relative sea level) during the interim. Nearby, shells in growth position overlying bedrock confirm that relative sea level was > 83 m asl by 38 010 ± 410 BP (minimum age). These marine deposits lie outside the last ice limit and are not overlain by glacigenic sediments.Distal to the last ice limit, Greely Fiord was occupied by the full glacial sea, whose limit is marked by discontinuous beaches and wave-cut benches. The full glacial sea rises from 116 m north of Greely Fiord to a maximum elevation of 148 m bordering its south shore from which it descends to 112 m asl near the head of Cañon Fiord. Numerous 14C dates on shells collected within 8 m of marine limit show that the full glacial sea remained stable from at least 8400 to 7400 BP. Several other shell samples collected ~20 m below marine limit are much older (> 22 000 BP). The position of relative sea level between ca. 8000 and > 22 000 BP is uncertain; however, stratigraphic evidence for an intervening regression has not been found.The modest extent of the last ice limit encircling Greely Fiord, together with its occupancy by the full glacial sea, is fully compatible with the paleogeography previously reported from northeast Ellesmere Island and northwest Greenland. Furthermore, this data base provides a reinterpretation of a 500 km transect previously reported along west-central Ellesmere Island to the south and affirms that the Innuitian Ice Sheet, defined sensu stricto for the last glaciation, is supplanted by the full glacial Innuitian Sea, which penetrated the Queen Elizabeth Islands, constraining the last ice limit.

Isostatic adjustments in a full glacial sea

1983 ◽  
Vol 20 (6) ◽  
pp. 895-917 ◽  
Author(s):  
John England
Keyword(s):  
Sea Level ◽  
Ellesmere Island ◽  
Relative Sea Level ◽  
Level Curves ◽  
Last Glaciation ◽  
Isostatic Equilibrium ◽  
Paleoclimatic Changes ◽  
History Of ◽  
Rapid Emergence

During the last glaciation an ice-free corridor existed between the northeast Ellesmere Island and northwest Greenland ice sheets. This corridor constituted a peripheral depression in which the marine limit marks the uppermost extent of a full glacial sea. The full glacial sea is characterized by (1) 14C dates on in situ marine shells that predate initial emergence (unloading) followed by (2) synchronous emergence from the marine limit throughout the peripheral depression. Relative sea-level curves from the full glacial sea confirm previous morphostratigraphic and glacioisostatic evidence for limited ice extent during the last glaciation. These curves also document the history of glacial unloading and the form of the relative sea-level curve that one would theoretically expect in the peripheral depression. The form of the curves presented here is unlike any other published emergence curves from arctic Canada or from Fennoscandia.The relative sea-level curves for northeast Ellesmere Island show three segments: (1) an interval of stable relative sea level (isostatic equilibrium) at the marine limit between at least 11 000 and 8000 BP; (2) an interval of slow emergence from 8000 to 6200 BP during which northeast Ellesmere Island ice slowly retreated; and (3) an interval of rapid emergence, caused by rapid glacial unloading, after 6200 BP when a prominent amelioration was in progress. These relative sea-level curves are discussed in relation to other paleoclimatic changes and the deglacial history of northwest Greenland. These curves are of regional importance in that they provide a new means of distinguishing between areas that were ice covered and ice free during the last glaciation.

Late Holocene relative sea level rise and the Neoglacial history of the Greenland ice sheet

2009 ◽  
Vol 24 (4) ◽  
pp. 345-359 ◽  
Author(s):  
Antony J. Long ◽  
Sarah A. Woodroffe ◽  
Sue Dawson ◽  
David H. Roberts ◽  
Charlotte L. Bryant
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Late Holocene ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Relative Sea Level ◽  
Relative Sea Level Rise ◽  
History Of

scholarly journals Former Ice Shelves in the Canadian High Arctic

1978 ◽  
Vol 20 (83) ◽  
pp. 393-404 ◽  
Author(s):  
John England ◽  
R. S. Bradley ◽  
G. H. Miller
Keyword(s):  
Sea Level ◽  
High Arctic ◽  
Ellesmere Island ◽  
Morphological Evidence ◽  
Canadian High Arctic ◽  
Relative Sea Level ◽  
Ice Shelves ◽  
Grounding Line ◽  
Water Depths ◽  
Age Estimates

AbstractMoraines deposited by the outermost ice advance across Judge Daly Promontory, northeastern Ellesmere Island, reflect thin, topographically controlled ice lobes extending to sea-level. The termini of two ice lobes were investigated and both produced ice shelves where they flowed into isostatically depressed embayments along western Kennedy Channel. Morphological evidence for these ice shelves occurs at the entrance to these valleys where steeply descending lateral moraines become abruptly horizontal for 2 km. In addition, both the horizontal moraines and associated pro-glacial terraces are fossiliferous down-valley from the apparent grounding line. Based on the differences in elevation between the horizontal moraines and the valley bottoms, the two ice shelves had estimated thicknesses ofc. 110 and 150 m. A proglacial outwash terrace at 175 m a.s.l. is considered to represent the approximate relative sea-level during the formation and break-up of the ice shelves. This relative sea-level is consistent with the water depths required to float the calculated ice thicknesses in both valleys. Associated with these ice margins are finite14C dates of 28 000-30 000 B.P. and amino-acid age estimates of >35 000 B.P. The importance and likelihood of additional past ice shelves in the Canadian High Arctic is discussed.

scholarly journals Former Ice Shelves in the Canadian High Arctic

1978 ◽  
Vol 20 (83) ◽  
pp. 393-404 ◽  
Author(s):  
John England ◽  
R. S. Bradley ◽  
G. H. Miller
Keyword(s):  
Sea Level ◽  
High Arctic ◽  
Ellesmere Island ◽  
Morphological Evidence ◽  
Canadian High Arctic ◽  
Relative Sea Level ◽  
Ice Shelves ◽  
Grounding Line ◽  
Water Depths ◽  
Age Estimates

AbstractMoraines deposited by the outermost ice advance across Judge Daly Promontory, northeastern Ellesmere Island, reflect thin, topographically controlled ice lobes extending to sea-level. The termini of two ice lobes were investigated and both produced ice shelves where they flowed into isostatically depressed embayments along western Kennedy Channel. Morphological evidence for these ice shelves occurs at the entrance to these valleys where steeply descending lateral moraines become abruptly horizontal for 2 km. In addition, both the horizontal moraines and associated pro-glacial terraces are fossiliferous down-valley from the apparent grounding line. Based on the differences in elevation between the horizontal moraines and the valley bottoms, the two ice shelves had estimated thicknesses ofc. 110 and 150 m. A proglacial outwash terrace at 175 m a.s.l. is considered to represent the approximate relative sea-level during the formation and break-up of the ice shelves. This relative sea-level is consistent with the water depths required to float the calculated ice thicknesses in both valleys. Associated with these ice margins are finite14C dates of 28 000-30 000 B.P. and amino-acid age estimates of >35 000 B.P. The importance and likelihood of additional past ice shelves in the Canadian High Arctic is discussed.

SEA-LEVELS, LATE QUATERNARY | Late Quaternary Relative Sea-Level Changes at Mid-Latitudes

2013 ◽  
pp. 489-494 ◽  
Author(s):  
A.C. Kemp ◽  
B.P. Horton ◽  
S.E. Engelhart
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Sea Levels

scholarly journals New relative sea-level insights into the isostatic history of the Western Mediterranean

2018 ◽  
Vol 201 ◽  
pp. 396-408 ◽  
Author(s):  
Matteo Vacchi ◽  
Matthieu Ghilardi ◽  
Rita T. Melis ◽  
Giorgio Spada ◽  
Matthieu Giaime ◽  
...  
Keyword(s):  
Sea Level ◽  
Western Mediterranean ◽  
Relative Sea Level ◽  
History Of

scholarly journals Lack of marine entry into Marmara and Black Sea-lakes indicate low relative sea level during MIS 3 in the northeastern Mediterranean

2019 ◽  
Author(s):  
Anastasia G. Yanchilina ◽  
Celine Grall ◽  
William B. F. Ryan ◽  
Jerry F. McManus ◽  
Candace O. Major
Keyword(s):  
Sea Level ◽  
Black Sea ◽  
Global Ocean ◽  
The Black Sea ◽  
Marmara Sea ◽  
Independent Data ◽  
Relative Sea Level ◽  
Mis 3 ◽  
History Of ◽  
Marine Isotope Stage 3

Abstract. The Marine Isotope Stage 3 (MIS 3) is considered a period of persistent and rapid climate and sea level variabilities during which eustatic sea level is observed to have varied by tens of meters. Constraints on local sea level during this time are critical for further estimates of these variabilities. We here present constraints on relative sea level in the Marmara and Black Sea regions in the northeastern Mediterranean, inferred from reconstructions of the history of the connections and disconnections (partial or total) of these seas together with the global ocean. We use a set of independent data from seismic imaging and core-analyses to infer that the Marmara and Black Seas remained connected persistent freshwater lakes that outflowed to the global ocean during the majority of MIS 3. Marine water intrusion during the early MIS-3 stage may have occurred into the Marmara Sea-Lake but not the Black Sea-Lake. This suggests that the relative sea level was near the paleo-elevation of the Bosporus sill and possibly slightly above the Dardanelles paleo-elevation, ~80 mbsl. The Eustatic sea level may have been even lower, considering the isostatic effects of the Eurasian ice sheet would have locally uplifted the topography of the northeastern Mediterrranean.

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