Stratigraphy, stable isotopes and salinity in multi-year sea ice from the rift area, south George VI Ice Shelf, Antarctic Peninsula

Tison, J.-L.; Morris, E.M.; Souchez, R.; Jouzel, J.. 1991 Stratigraphy, stable isotopes and salinity in multi-year sea ice from the rift area, south George VI Ice Shelf, Antarctic Peninsula. Journal of Glaciology, 37 (127). 357-367. 10.3189/S0022143000005797

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Official URL: http://dx.doi.org/10.3189/S0022143000005797

Abstract/Summary

Results from a detailed profile in a 5.54 m multi-year sea-ice core from the rift area in the southern part of George VI Ice Shelf are presented. Stratigraphy, stable isotopes and Na content are used to investigate the growth processes of the ice cover and to relate them to melting processes at the bottom of the ice shelf. The thickest multi-year sea ice in the sampling area appears to be second-year sea ice that has survived one melt season. Combined salinity/stable-isotope analyses show large-scale sympathetic fluctuations that can be related to the origin of the parent water. Winter accretion represents half of the core length and mainly consists of frazil ice of normal sea-water origin. However, five major dilution events of sea water, with fresh-water input from the melting base of the ice shelf reaching 20% on two occasions, punctuate this winter accretion. Two of them correspond to platelet-ice production, which is often related to the freezing of ascending supercooled water from the bottom of the ice shelf. Brackish ice occurs between 450 and 530 cm in the core. It is demonstrated that this results from the freezing of brackish water (Jeffries and others, 1989) formed by mixing of normal sea water with melted basal shelf ice, with dilution percentages of maximum 80% fresh water.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.3189/S0022143000005797
ISSN:	0022-1430
Date made live:	07 Jun 2018 10:50 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/520218

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.3189/S0022143000005797

ISSN:

0022-1430

Date made live:

07 Jun 2018 10:50 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/520218