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dc.contributor.authorPattan, J.N.
dc.contributor.authorParthiban, G.P.S.
dc.date.accessioned2007-07-25T07:21:58Z
dc.date.available2007-07-25T07:21:58Z
dc.date.issued2007
dc.identifier.citationJournal of Asian Earth Sciences, vol.30(5-6); 696-705p.
dc.identifier.urihttp://drs.nio.org/drs/handle/2264/636
dc.description.abstractFifty buried manganese nodules at different depth intervals were recovered in 12 sediment cores from the Central Indian Ocean Basin (CIOB). A maximum of 15 buried nodules were encountered in one sediment core (AAS-22/GC-07) and the deepest nodule was recovered at 5.50 m below seafloor in core AAS-04/GC-5A. Approximately 80% of the buried nodules are small in size (approx. 2 cm diameter) in contrast to the Atlantic Ocean and Peru Basin (Pacific Ocean) where the majority of the buried nodules are large, approx. 8 cm and > 6 cm, respectively. Buried nodule size decreases with core depth and this distribution appears to be similar to the phenomenon of ‘Brazil Nut Effect’. Buried nodules exhibit both smooth and rough surface textures and are ellipsoidal, elongated, rounded, sub rounded, irregular and polynucleated. Buried nodules from siliceous ooze are enriched in Mn, Cu, Ni, Zn, Mo, Ga, V and Rb whereas those from red clay are enriched in Fe, Co, Ti, U, Th, Y, Cr, Nb and Rare Earth Elements (REE). Buried nodules from siliceous ooze suggest their formation under hydrogenetic, early digenetic and diagenetic processes whereas those from red clay are of hydrogenetic origin. REE are enriched more than 1.5 times in buried nodules from red clay compared to siliceous ooze. However, the mode of incorporation of REE into buried nodules from both sedimentary environments is by a single authigenic phase consisting of Fe-Ti-P. Shalenormalized REE patterns and Ce anomalies suggest that nodules from siliceous ooze formed under more oxidizing conditions than those from red clay. Nodules buried at depths between 1.5 and 2.5 m are diagenetic (Mn/Fe ratio 10-15), formed in highly oxic environments (large positive Ce anomalies) and record aeolian dust (high Eu anomalies). Chemical composition, surface texture and morphology of buried nodules are similar to those of surface nodules from the same basin. Furthermore, buried nodule compositions do not exhibit any distinct patterns within the core depth, suggesting that buried nodules neither grow nor dissolve after their burial in the sediment column.
dc.format.extent687360 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherElsevier
dc.rightsAn edited version of this paper was published by Elsevier. Copyright [2007] Elsevier
dc.subjectBuried nodules
dc.subjectCentral Indian Ocean
dc.subjectSiliceous ooze
dc.subjectRed clay
dc.titleDo manganese nodules grow or dissolve after burial? Results from the Central Indian Ocean Basin
dc.typeJournal Article


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