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dc.contributor.authorRao, V.P.
dc.contributor.authorKessarkar, P.M.
dc.contributor.authorKrumbein, W.E.
dc.contributor.authorKrajewski, K.P.
dc.contributor.authorSchneider, R.J.
dc.date.accessioned2008-07-18T05:45:18Z
dc.date.available2008-07-18T05:45:18Z
dc.date.issued2003
dc.identifier.citationSedimentology, Vol.50; 819-830p.
dc.identifier.urihttp://drs.nio.org/drs/handle/2264/1257
dc.description.abstractThe occurrence of Late Pleistocene dolomite crusts that occur at 64 m depth on the carbonate platform off western India is documented. Dolomite is the most predominant mineral in the crusts. In thin section, the crust consists of dolomitized microlaminae interspersed with detrital particles. Under scanning electron microscopy, these laminae are made up of tubular filaments or cellular structures of probable cyanobacterial origin. Dolomite crystals encrust or overgrow the surfaces of the microbial filaments and/or cells; progressive mineralization obliterates their morphology. Well-preserved microbial mats, sulphide minerals (pyrrhotite and marcasite) and the stable isotope composition of dolomite in the crusts indicate hypersaline and anoxic conditions during dolomite formulation. The crusts are similar to dolomite stromatolites, and biogeochemical processes related to decaying microbial mats under anoxic conditions probably played an important role in dolomite precipitation. The dolomite is therefore primary and/or very early diagenetic in origin. The dolomite crusts are interpreted to be a composite of microbial dolomite overprinted by early burial organic dolomite. The results of this study suggest that a microbial model for dolomite formation may be relevant for the origin of ancient massive dolomites in marine successions characterized by cryptalgal laminites. The age of the crusts further suggests that the platform was situated at shallow subtidal depths during the Last Glacial Maximum
dc.language.isoen
dc.publisherInternational Association of Sedimentologists
dc.rightsCopyright [2003]. It is tried to respect the rights of the copyright holders to the best of the knowledge. If it is brought to our notice that the rights are violated then the item would be withdrawn.
dc.subjectdolomite
dc.subjectstromatolites
dc.subjectcarbonates
dc.subjectpleistocene
dc.subjectconcretions
dc.subjectmicrobiology
dc.subjectanoxic conditions
dc.titleMicrobial dolomite crusts from the carbonate platform off western India
dc.typeJournal Article


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