Authigenic carbonates in the sediments of Goa offshore basin, western continental margin of India

Show simple item record Kocherla, M. 2012-05-09T10:45:20Z 2012-05-09T10:45:20Z 2012
dc.identifier.citation Current Science, vol.102(8); 2012; 1205-1211
dc.description.abstract Euhedral crystals (approx. 1 mm) of authigenic carbonates are identified in 5 m long sediment cores collected from the western continental margin of India in water depths between 2665 and 3070 m. Low-Mg calcite and aragonite are the dominant authigenic minerals while high-Mg calcite, dolomite and siderite occur in minor amounts. Morphological evidences such as euhedral carbonate crystals and slender radiating aragonite crystals suggest that they are formed authigenically in the sediment column. The delta sup(13)C values of the authigenic carbonates range between 0.63ppt and -8.12 ppt, and is attributed to the contribution of isotopically light carbon derived from the oxidation of sedimentary organic matter in the surficial sub-oxic Fe reduction and the bacterial sulphate reduction zone during early diagenesis. Mineralogy, morphology and stable carbon isotope signatures of authigenic carbonates and the occurrence of pyrite framboids and octahedral crystals and the evaluation of pore-fluid chemistry argue against a precipitation of carbonates due to anaerobic oxidation of methane and refute the possible connection of methane gas from the shallow gascharged sediments to the observed carbonates.
dc.language.iso en
dc.publisher Current Science Association
dc.rights Copyright [2012]. All efforts have been made to respect the copyright to the best of our knowledge. Inadvertent omissions, if brought to our notice, stand for correction and withdrawal of document from this repository.
dc.subject sediments
dc.subject authigenic minerals
dc.subject carbonates
dc.title Authigenic carbonates in the sediments of Goa offshore basin, western continental margin of India
dc.type Journal Article

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