Shelf, Coastal and Subglacial Polar Carbonates, East Antarctica
Modern and Pleistocene polar carbonates occur in East Antarctica in shelf, coast, lakes and marginal to underneath glaciers, associated mainly with glacigene muds, boulder tills and diamictites. Shelf carbonates (in Prydz Bay) are calcitic and unlithified, and consist mainly of sponges, bryozoans, e...
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Online Access: | https://doi.org/10.1007/BF03176591 http://ecite.utas.edu.au/15046 |
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ftunivtasecite:oai:ecite.utas.edu.au:15046 2023-05-15T13:59:07+02:00 Shelf, Coastal and Subglacial Polar Carbonates, East Antarctica Rao, CP Goodwin, ID Gibson, JAE 1998 https://doi.org/10.1007/BF03176591 http://ecite.utas.edu.au/15046 en eng Northeastern Science Foundation Inc http://dx.doi.org/10.1007/BF03176591 Rao, CP and Goodwin, ID and Gibson, JAE, Shelf, Coastal and Subglacial Polar Carbonates, East Antarctica, Carbonates and Evaporites, 13, (2) pp. 174-188. ISSN 0891-2556 (1998) [Refereed Article] http://ecite.utas.edu.au/15046 Earth Sciences Geochemistry Organic Geochemistry Refereed Article PeerReviewed 1998 ftunivtasecite https://doi.org/10.1007/BF03176591 2019-12-13T20:59:08Z Modern and Pleistocene polar carbonates occur in East Antarctica in shelf, coast, lakes and marginal to underneath glaciers, associated mainly with glacigene muds, boulder tills and diamictites. Shelf carbonates (in Prydz Bay) are calcitic and unlithified, and consist mainly of sponges, bryozoans, echinoderms, bivalves and diatoms. Coastal carbonates (in the Vestfold Hills) are calcitic and contain faunal assemblages similar to those on the shelf, with calcareous algae, microbial mats, minor peloids and cements. Lake carbonates are aragonitic micrites and peloids. Carbonates close to glaciers (the Loken Moraines) are aragonitic and contain abundant ooids with intragranular fibrous cements. Subglacial carbonates are aragonitic micrites and peloids. Carbonate mineralogy changes from mainly low-Mg calcite in marine shelf to aragonite in brackish to freshwater dominated inland regions. Antarctic carbonate 18O values (4.5 to -47 PDB) vary markedly due to frigid temperatures (0 to -2C) and salinity (0 to 35) changes, as a result of meltwater dilution from adjacent glaciers. Their 13C values (-9 to 8 PDB) also vary markedly due to exposure to atmospheric CO2, the circulation of water masses and reaction of carbonate with CO2 trapped in glacial ice. The regional distribution of carbonate sediments and their sedimentology, mineralogy, and 18O and 13C compositions indicate three types of glacial environments of formation. The first corresponds to a glacial stage and the formation of subglacial and bank carbonates, when the Antarctic ice sheet expanded onto the inner shelves. The second corresponds to interglacial stages and the formation of ice-marginal carbonates, during the retreat of the ice sheet from the inner shelf grounding line and accompanying the discharge of appreciable meltwater. The third corresponds to an interglacial oasis and the formation of coastal carbonates, proximal to distal lacustrine carbonates, and distal subglacial carbonates. Article in Journal/Newspaper Antarc* Antarctic Antarctica East Antarctica Ice Sheet Prydz Bay eCite UTAS (University of Tasmania) Antarctic East Antarctica Loken ENVELOPE(18.549,18.549,68.798,68.798) Loken Moraines ENVELOPE(110.617,110.617,-66.283,-66.283) Prydz Bay The Antarctic Vestfold Vestfold Hills Carbonates and Evaporites 13 2 174 188 |
institution |
Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Geochemistry Organic Geochemistry |
spellingShingle |
Earth Sciences Geochemistry Organic Geochemistry Rao, CP Goodwin, ID Gibson, JAE Shelf, Coastal and Subglacial Polar Carbonates, East Antarctica |
topic_facet |
Earth Sciences Geochemistry Organic Geochemistry |
description |
Modern and Pleistocene polar carbonates occur in East Antarctica in shelf, coast, lakes and marginal to underneath glaciers, associated mainly with glacigene muds, boulder tills and diamictites. Shelf carbonates (in Prydz Bay) are calcitic and unlithified, and consist mainly of sponges, bryozoans, echinoderms, bivalves and diatoms. Coastal carbonates (in the Vestfold Hills) are calcitic and contain faunal assemblages similar to those on the shelf, with calcareous algae, microbial mats, minor peloids and cements. Lake carbonates are aragonitic micrites and peloids. Carbonates close to glaciers (the Loken Moraines) are aragonitic and contain abundant ooids with intragranular fibrous cements. Subglacial carbonates are aragonitic micrites and peloids. Carbonate mineralogy changes from mainly low-Mg calcite in marine shelf to aragonite in brackish to freshwater dominated inland regions. Antarctic carbonate 18O values (4.5 to -47 PDB) vary markedly due to frigid temperatures (0 to -2C) and salinity (0 to 35) changes, as a result of meltwater dilution from adjacent glaciers. Their 13C values (-9 to 8 PDB) also vary markedly due to exposure to atmospheric CO2, the circulation of water masses and reaction of carbonate with CO2 trapped in glacial ice. The regional distribution of carbonate sediments and their sedimentology, mineralogy, and 18O and 13C compositions indicate three types of glacial environments of formation. The first corresponds to a glacial stage and the formation of subglacial and bank carbonates, when the Antarctic ice sheet expanded onto the inner shelves. The second corresponds to interglacial stages and the formation of ice-marginal carbonates, during the retreat of the ice sheet from the inner shelf grounding line and accompanying the discharge of appreciable meltwater. The third corresponds to an interglacial oasis and the formation of coastal carbonates, proximal to distal lacustrine carbonates, and distal subglacial carbonates. |
format |
Article in Journal/Newspaper |
author |
Rao, CP Goodwin, ID Gibson, JAE |
author_facet |
Rao, CP Goodwin, ID Gibson, JAE |
author_sort |
Rao, CP |
title |
Shelf, Coastal and Subglacial Polar Carbonates, East Antarctica |
title_short |
Shelf, Coastal and Subglacial Polar Carbonates, East Antarctica |
title_full |
Shelf, Coastal and Subglacial Polar Carbonates, East Antarctica |
title_fullStr |
Shelf, Coastal and Subglacial Polar Carbonates, East Antarctica |
title_full_unstemmed |
Shelf, Coastal and Subglacial Polar Carbonates, East Antarctica |
title_sort |
shelf, coastal and subglacial polar carbonates, east antarctica |
publisher |
Northeastern Science Foundation Inc |
publishDate |
1998 |
url |
https://doi.org/10.1007/BF03176591 http://ecite.utas.edu.au/15046 |
long_lat |
ENVELOPE(18.549,18.549,68.798,68.798) ENVELOPE(110.617,110.617,-66.283,-66.283) |
geographic |
Antarctic East Antarctica Loken Loken Moraines Prydz Bay The Antarctic Vestfold Vestfold Hills |
geographic_facet |
Antarctic East Antarctica Loken Loken Moraines Prydz Bay The Antarctic Vestfold Vestfold Hills |
genre |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet Prydz Bay |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet Prydz Bay |
op_relation |
http://dx.doi.org/10.1007/BF03176591 Rao, CP and Goodwin, ID and Gibson, JAE, Shelf, Coastal and Subglacial Polar Carbonates, East Antarctica, Carbonates and Evaporites, 13, (2) pp. 174-188. ISSN 0891-2556 (1998) [Refereed Article] http://ecite.utas.edu.au/15046 |
op_doi |
https://doi.org/10.1007/BF03176591 |
container_title |
Carbonates and Evaporites |
container_volume |
13 |
container_issue |
2 |
container_start_page |
174 |
op_container_end_page |
188 |
_version_ |
1766267494313492480 |