Gas Inclusions in the Antarctic Ice Sheet and Their Significance

Gas Inclusions in the Antarctic Ice Sheet and Their Significance PDF Author: Anthony J. Gow
Publisher:
ISBN:
Category : Bubbles
Languages : en
Pages : 28

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Book Description
Cores obtained to the bottom of the Antarctic Ice Sheet at Byrd Station were used to analyze the physical properties of air bubbles trapped in the ice. Parameters measured were the sizes, shapes, abundances, spatial distributions, gas volumes and pressure of bubbles, and their variations with depth in the ice sheet. Bubbles occur abundantly in the top 800 m of ice but then gradually disappear until they can no longer be detected optically below 1100 m. This disappearance is not accompanied by any significant loss of air from the ice and all available evidence indicates that the air actually diffuses into the ice in response to increasing overburden pressure. Bubble pressure measurements show that (1) bubbles with pressures exceeding about 16 bars begin to relax back to this value soon after in situ pressures are relieved by drilling, (2) further slow decompression occurs with time, and (3) the rate of decompression is controlled to some extent by the intrinsic structural properties of the ice and its thermal and deformational history. Only small variations were observed in the entrapped air content of the ice cores; they probably reflect variations in the temperature and/or pressure of the air at the time of its entrapment, but the data are not sufficient to draw any firm conclusions regarding past variations in ice sheet thickness. Only ice from the bottom 4.83 m was found to lack any detectable trace of air.

Gas Inclusions in the Antarctic Ice Sheet and Their Significance

Gas Inclusions in the Antarctic Ice Sheet and Their Significance PDF Author: Anthony J. Gow
Publisher:
ISBN:
Category : Bubbles
Languages : en
Pages : 28

Get Book Here

Book Description
Cores obtained to the bottom of the Antarctic Ice Sheet at Byrd Station were used to analyze the physical properties of air bubbles trapped in the ice. Parameters measured were the sizes, shapes, abundances, spatial distributions, gas volumes and pressure of bubbles, and their variations with depth in the ice sheet. Bubbles occur abundantly in the top 800 m of ice but then gradually disappear until they can no longer be detected optically below 1100 m. This disappearance is not accompanied by any significant loss of air from the ice and all available evidence indicates that the air actually diffuses into the ice in response to increasing overburden pressure. Bubble pressure measurements show that (1) bubbles with pressures exceeding about 16 bars begin to relax back to this value soon after in situ pressures are relieved by drilling, (2) further slow decompression occurs with time, and (3) the rate of decompression is controlled to some extent by the intrinsic structural properties of the ice and its thermal and deformational history. Only small variations were observed in the entrapped air content of the ice cores; they probably reflect variations in the temperature and/or pressure of the air at the time of its entrapment, but the data are not sufficient to draw any firm conclusions regarding past variations in ice sheet thickness. Only ice from the bottom 4.83 m was found to lack any detectable trace of air.

Gas Inclusions in the Antarctic Ice Sheet and Their Significance

Gas Inclusions in the Antarctic Ice Sheet and Their Significance PDF Author: Anthony J. Gow
Publisher:
ISBN:
Category : Bubbles
Languages : en
Pages : 0

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Book Description
Cores obtained to the bottom of the Antarctic Ice Sheet at Byrd Station were used to analyze the physical properties of air bubbles trapped in the ice. Parameters measured were the sizes, shapes, abundances, spatial distributions, gas volumes and pressure of bubbles, and their variations with depth in the ice sheet. Bubbles occur abundantly in the top 800 m of ice but then gradually disappear until they can no longer be detected optically below 1100 m. This disappearance is not accompanied by any significant loss of air from the ice and all available evidence indicates that the air actually diffuses into the ice in response to increasing overburden pressure. Bubble pressure measurements show that (1) bubbles with pressures exceeding about 16 bars begin to relax back to this value soon after in situ pressures are relieved by drilling, (2) further slow decompression occurs with time, and (3) the rate of decompression is controlled to some extent by the intrinsic structural properties of the ice and its thermal and deformational history. Only small variations were observed in the entrapped air content of the ice cores; they probably reflect variations in the temperature and/or pressure of the air at the time of its entrapment, but the data are not sufficient to draw any firm conclusions regarding past variations in ice sheet thickness. Only ice from the bottom 4.83 m was found to lack any detectable trace of air.

Fluid inclusions

Fluid inclusions PDF Author: Edwin Roedder
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 150150827X
Category : Science
Languages : en
Pages : 652

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Book Description
Volume 12 of Reviews in Mineralogy introduces to fluid inclusions. It covers the folowing questions: when and where inclusions form. how they change, how to prepare material and make microthermometric measurementsl, how to interpret these data, and what has been found in applications of fluid-inclusion studies to each of a series of different geologic environments. This book also attempts to discuss the many applications of fluid inclusions to the study of and understanding of geologic processes and the geologic environments in which they acted.

Technical Report

Technical Report PDF Author: Cold Regions Research and Engineering Laboratory (U.S.)
Publisher:
ISBN:
Category : Frozen ground
Languages : en
Pages : 610

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Book Description


Monthly Catalog of United States Government Publications

Monthly Catalog of United States Government Publications PDF Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1814

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Book Description


The Physics of Glaciers

The Physics of Glaciers PDF Author: W. S. B. Paterson
Publisher: Elsevier
ISBN: 1483287254
Category : Science
Languages : en
Pages : 491

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Book Description
This updated and expanded version of the second edition explains the physical principles underlying the behaviour of glaciers and ice sheets. The text has been revised in order to keep pace with the extensive developments which have occurred since 1981. A new chapter, of major interest, concentrates on the deformation of subglacial till. The book concludes with a chapter on information regarding past climate and atmospheric composition obtainable from ice cores.

CRREL Technical Publications

CRREL Technical Publications PDF Author: Cold Regions Research and Engineering Laboratory (U.S.)
Publisher:
ISBN:
Category : Engineering
Languages : en
Pages : 178

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Book Description


Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1072

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Book Description


Research Report - Corps of Engineers, U.S. Army, Cold Regions Research and Engineering Laboratory

Research Report - Corps of Engineers, U.S. Army, Cold Regions Research and Engineering Laboratory PDF Author: Cold Regions Research and Engineering Laboratory (U.S.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 334

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Book Description


The EPICA-DML Deep Ice Core

The EPICA-DML Deep Ice Core PDF Author: Sérgio Henrique Faria
Publisher: Springer
ISBN: 3662553082
Category : Science
Languages : en
Pages : 312

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Book Description
The line-scan images collected in this book represent the most accurate optical record of Antarctic ice cores ever presented, providing an invaluable resource for glaciologists and climate modellers, as well as a fascinating compilation of ice core images for Antarctica enthusiasts. Global warming and the Earth’s past climate are the two main reasons for extracting deep ice cores from Antarctica. Indeed, dust particles, aerosols and other climatic traces deposited on the snow surface, as well as the air trapped in bubbles by compacted snow, produce chronologically ordered strata, making the ice from Antarctica the most accurate and valuable archive of the Earth’s climate over the last million years. In addition, the layered structure produced by these strata, when revealed by appropriate methods, provides indispensable information concerning the flow and mechanical stability of the Antarctic ice sheet, allowing us to assess the current and future impact of global warming on the melting of polar ice caps with much greater precision.