scholarly journals Holocene emergence and shoreline delevelling, southern Eureka Sound, High Arctic Canada

2002 ◽  
Vol 53 (2) ◽  
pp. 235-247 ◽  
Author(s):  
Colm Ó Cofaigh
Keyword(s):  
Sea Level ◽  
High Arctic ◽  
Arctic Canada ◽  
Relative Sea Level ◽  
Geological Evidence ◽  
Level Curves ◽  
A Cell ◽  
Late Wisconsinan ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract This paper is a reconstruction of postglacial relative sea level change and shoreline delevelling in southern Eureka Sound, High Arctic Canada. Postglacial emergence of up to 150 m is recorded in this area by raised marine deltas, beaches and washing limits that date from the early Holocene. Marine limit is metachronous and formed successively with glacier retreat. Marked contrasts in the form of relative sea level curves and rate of initial emergence are recorded from the study area. In Blind Fiord, relative sea level fell continuously following deglaciation. Initial emergence was characterised by rates of ≥ 5 m/century. This contrasts with curves from Starfish and Irene bays, where the rate of initial emergence was ≤ 1 m/century. Isobases drawn on the 8.5 ka shoreline for greater Eureka Sound demonstrate that a cell of highest emergence (≥ 130 m asl) extends along the length of the channel, and closes in the vicinity of the entrance to Norwegian Bay. This pattern confirms a distinct loading centre over Eureka Sound during the Last Glacial Maximum, and is compatible with independent glacial geological evidence indicating that the thickest ice was centred over the channel during the Late Wisconsinan.

A comparison of observed and theoretical postglacial relative sea level in Atlantic Canada

1981 ◽  
Vol 18 (7) ◽  
pp. 1146-1163 ◽  
Author(s):  
Garry Quinlan ◽  
Christopher Beaumont
Keyword(s):  
Sea Level ◽  
Field Data ◽  
Sea Level Change ◽  
Atlantic Canada ◽  
Relative Sea Level ◽  
Level Curves ◽  
Level Change ◽  
The Common ◽  
Late Wisconsinan ◽  
Outermost Zone

Two extreme models of late Wisconsinan ice cover in Atlantic Canada and the northeastern U.S.A. are shown to produce postglacial relative sea level curves that bracket existing field observations at six sites throughout the region. This suggests that the true late Wisconsinan ice distribution is probably intermediate to the two contrasting reconstructions proposed. Both ice models predict the existence of four relative sea level zones: an innermost zone closest to the centre of glaciation in which relative sea level falls continuously throughout postglacial time; an outermost zone in which it rises continuously; and two transitional zones in which it first falls and then rises in varying proportions according to the distance from the ice margin. The distinctive forms of the relative sea level curves are probably representative of each of the zones and are unlikely to be significantly perturbed even by large local ice readvances. They, therefore, establish patterns with which future field data are expected to conform. The form that the geological record of relative sea level change is likely to take within each zone is discussed and promising settings for the collection of new data are proposed. The common practice of separating relative sea level into an isostatic and a eustatic component is analysed and shown to be incorrect as usually applied. The practice is also shown to be unnecessary because the models discussed in this paper predict changes in relative sea level that can be compared directly with the observations.

Global Changes in Postglacial Sea Level: A Numerical Calculation

1978 ◽  
Vol 9 (3) ◽  
pp. 265-287 ◽  
Author(s):  
James A. Clark ◽  
William E. Farrell ◽  
W.Richard Peltier
Keyword(s):  
Sea Level ◽  
Close Agreement ◽  
Ice Sheets ◽  
Specific Form ◽  
Global Changes ◽  
Level Curve ◽  
Relative Sea Level ◽  
The Past ◽  
The Last Glacial Maximum ◽  
The Last Glacial

The sea-level rise due to ice-sheet melting since the last glacial maximum was not uniform everywhere because of the deformation of the Earth's surface and its geoid by changing ice and water loads. A numerical model is employed to calculate global changes in relative sea level on a spherical viscoelastic Earth as northern hemisphere ice sheets melt and fill the ocean basins with meltwater. Predictions for the past 16,000 years explain a large proportion of the global variance in the sea-level record, particularly during the Holocene. Results indicate that the oceans can be divided into six zones, each of which is characterized by a specific form of the relative sea-level curve. In four of these zones emerged beaches are predicted, and these may form even at considerable distance from the ice sheets themselves. In the remaining zones submergence is dominant, and no emerged beaches are expected. The close agreement of these predictions with the data suggests that, contrary to the beliefs of many, no net change in ocean volume has occurred during the past 5000 years. Predictions for localities close to the ice sheets are the most in error, suggesting that slight modifications of the assumed melting history and/or the rheological model of the Earth's interior are necessary.

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