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Shelf, Coastal and Subglacial Polar Carbonates, East Antarctica

Citation

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]

DOI: doi:10.1007/BF03176591

Abstract

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 δ18O values (4.5 to -47‰ PDB) vary markedly due to frigid temperatures (0 to -2°C) and salinity (0 to 35‰) changes, as a result of meltwater dilution from adjacent glaciers. Their δ13C 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 δ18O and δ13C 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.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geochemistry
Research Field:Organic Geochemistry
Objective Division:Environment
Objective Group:Land and Water Management
Objective Field:Antarctic and Sub-Antarctic Land and Water Management
Author:Rao, CP (Dr Prasada Rao)
Author:Goodwin, ID (Associate Professor Ian Goodwin)
Author:Gibson, JAE (Dr John Gibson)
ID Code:15046
Year Published:1998
Web of Science® Times Cited:8
Deposited By:IASOS
Deposited On:1998-08-01
Last Modified:2011-08-09
Downloads:0

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