Call number:
ZSP-201-82/39
In:
CRREL Report, 82-39
Description / Table of Contents:
Observations of a 4.4-m-high brine step in the McMurdo Ice Shelf, Antarctica, show that it has migrated about 1.2 km in 4 years. The present brine wave is overriding an older brine-soaked layer. This migration is proof of the dynamic nature of the step, which is the leading edge of a brine wave that originated at the shelf edge after a major break-out of the McMurdo Ice Shelf. The inland boundary of brine penetration is characterized by a series of descending steps that are believed to represent terminal positions of separate intrusions of brine of similar origin. The inland boundary of brine percolation is probably controlled largely by the depth at which brine encounters the firn/ ice transition (43 m). However, this boundary is not fixed by permeability considerations alone, since measurable movement of brine is still occurring at the inland boundary. Freeze-fractionation of the seawater as it migrates throught the ice shelf preferentially precipitates virtually all sodium sulfate, and concomitant removal of water by freezing in the pore spaces of the infiltrated firm produces residual brines approximately six times more concentrated than the original seawater.
Type of Medium:
Series available for loan
Pages:
v, 35 Seiten
,
Illustrationen
Series Statement:
CRREL Report 82-39
URL:
https://apps.dtic.mil/docs/citations/ADA124516
URL:
https://hdl.handle.net/11681/9319
Language:
English
Note:
CONTENTS
Abstract
Preface
Introduction
Objectives
Analytical techniques
Radio echo profiling
Core drilling
Results and discussion
Brine infiltration survey
Brine layer steps
Brine infiltration characteristics
Brine infiltration mechanisms at inland boundary
Confirmation of brine depths by drilling
Density and temperature profiles
Ice shelf freeboard
Brine upwelling
Brine chemistry
Conclusions
Literature cited
Location:
AWI Archive
Branch Library:
AWI Library
