Data

Trace Element Chemistry of Antarctic Saline Lakes and Fjords

Australian Antarctic Division
O'Grady, B. ; O'GRADY, BARRY
Viewed: [[ro.stat.viewed]] Cited: [[ro.stat.cited]] Accessed: [[ro.stat.accessed]]
ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rfr_id=info%3Asid%2FANDS&rft_id=http://data.aad.gov.au/metadata/ASAC_568&rft.title=Trace Element Chemistry of Antarctic Saline Lakes and Fjords&rft.identifier=http://data.aad.gov.au/metadata/ASAC_568&rft.publisher=Australian Antarctic Data Centre&rft.description=From the referenced paper:The frigid concentration or freezing of seawater is an important natural phenomenon in the polar regions and results in the precipitation of a different sequence of salts - and thus produces brines of different composition - to that formed during isothermal evaporation under temperate conditions (about 20-25 degrees C). Seawater freezing, however, has been studied less extensively than evaporation and somewhat greater uncertainty exists over the exact nature of the compositional pathway followed. Most investigators have shown that the precipitation of mirabilite (Na2SO4 - 10 H2O) or gypsum (CaSO4 - 2 H2O), which both occur at the same seawater concentration factor (SWCF), is the critical difference between frigid and evaporative concentration, respectively, a consequence of the very different temperature dependence of the solubilities of these salts, as well as the effect of sodium chloride on these properties. This difference can be considered to represent a temperature-dependent chemical divide in the closed-basin concentration of seawater because it determines significantly the major ion composition of the brine and the salt mineral assemblage precipitated on further evolution of the system. Recently new insights into seawater freezing have been achieved through improvements in existing chemical equilibrium models. Along with the results of some associated experimental work, this has provided evidence for the formation of gypsum during freezing, contradicting the accepted Ringer-Nelson-Thompson model of frigid concentration firmly established in the 1950's and through subsequent studies, but validating an alternative model proposed by Gitterman two decades later.Progress Code: completedStatement: Dates provided in temporal coverage are approximate only.&rft.creator=O'Grady, B. &rft.creator=O'GRADY, BARRY &rft.date=2000&rft.coverage=westlimit=78.0; southlimit=-69.0; eastlimit=79.0; northlimit=-68.0&rft.coverage=westlimit=78.0; southlimit=-69.0; eastlimit=79.0; northlimit=-68.0&rft_rights=A PDF copy of the referenced paper is available for download from the provided URL to AAD staff only.&rft_rights=Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/legalcode&rft_rights=This data set conforms to the CCBY Attribution License (http://creativecommons.org/licenses/by/4.0/). Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=ASAC_568 when using these data.&rft_rights=This metadata record is publicly available.&rft_subject=geoscientificInformation&rft_subject=inlandWaters&rft_subject=oceans&rft_subject=EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SNOW/ICE > LAKE ICE&rft_subject=EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SURFACE WATER > SURFACE WATER FEATURES > LAKES/RESERVOIRS&rft_subject=EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > FRESHWATER ECOSYSTEMS > LAKE/POND > SALINE LAKES&rft_subject=ANTARCTIC&rft_subject=ANTARCTICA&rft_subject=LAKES&rft_subject=SALINE LAKES&rft_subject=SEA WATER&rft_subject=VESTFOLD HILLS&rft_subject=AMD/AU&rft_subject=CEOS&rft_subject=AMD&rft_subject=CONTINENT > ANTARCTICA > Vestfold Hills&rft_subject=GEOGRAPHIC REGION > POLAR&rft.type=dataset&rft.language=English Access the data
Cite Saved to MyRDA Save to MyRDA

Licence & Rights:

Open Licence view details
CC-BY

Attribution 4.0 International (CC BY 4.0)
https://creativecommons.org/licenses/by/4.0/legalcode

A PDF copy of the referenced paper is available for download from the provided URL to AAD staff only.

This data set conforms to the CCBY Attribution License (http://creativecommons.org/licenses/by/4.0/). Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=ASAC_568 when using these data.

This metadata record is publicly available.

Access:

Other

Full description

From the referenced paper:

The frigid concentration or freezing of seawater is an important natural phenomenon in the polar regions and results in the precipitation of a different sequence of salts - and thus produces brines of different composition - to that formed during isothermal evaporation under temperate conditions (about 20-25 degrees C). Seawater freezing, however, has been studied less extensively than evaporation and somewhat greater uncertainty exists over the exact nature of the compositional pathway followed. Most investigators have shown that the precipitation of mirabilite (Na2SO4 - 10 H2O) or gypsum (CaSO4 - 2 H2O), which both occur at the same seawater concentration factor (SWCF), is the critical difference between frigid and evaporative concentration, respectively, a consequence of the very different temperature dependence of the solubilities of these salts, as well as the effect of sodium chloride on these properties. This difference can be considered to represent a temperature-dependent chemical divide in the closed-basin concentration of seawater because it determines significantly the major ion composition of the brine and the salt mineral assemblage precipitated on further evolution of the system. Recently new insights into seawater freezing have been achieved through improvements in existing chemical equilibrium models. Along with the results of some associated experimental work, this has provided evidence for the formation of gypsum during freezing, contradicting the accepted Ringer-Nelson-Thompson model of frigid concentration firmly established in the 1950's and through subsequent studies, but validating an alternative model proposed by Gitterman two decades later.

Lineage

Progress Code: completed
Statement: Dates provided in temporal coverage are approximate only.

Data time period: 1992-10-01 to 1995-03-31

This dataset is part of a larger collection

Click to explore relationships graph
Help

Related People

79,-68 79,-69 78,-69 78,-68 79,-68

78.5,-68.5

text: westlimit=78.0; southlimit=-69.0; eastlimit=79.0; northlimit=-68.0

Subjects
AMD | AMD/AU | ANTARCTIC | ANTARCTICA | CEOS | CONTINENT > ANTARCTICA > Vestfold Hills | EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > FRESHWATER ECOSYSTEMS > LAKE/POND > SALINE LAKES | EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SNOW/ICE > LAKE ICE | EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SURFACE WATER > SURFACE WATER FEATURES > LAKES/RESERVOIRS | GEOGRAPHIC REGION > POLAR | LAKES | SALINE LAKES | SEA WATER | VESTFOLD HILLS | geoscientificInformation | inlandWaters | oceans |

User Contributed Tags    

Login to tag this record with meaningful keywords to make it easier to discover

Other Information
Public information for ASAC project 568 (PROJECT HOME PAGE)

url : https://projects.aad.gov.au/search_projects_results.cfm?project_no=568

Download point for the paper - AAD Staff Only (VIEW RELATED INFORMATION > PUBLICATIONS)

url : http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=1597

Citation reference for this metadata record and dataset (VIEW RELATED INFORMATION)

url : http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=ASAC_568

Identifiers
  • global : ASAC_568
ACN 633 798 857