Alterations in geochemical associations in artificially disturbed deep-sea sediments

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dc.contributor.author Nath, B.N.
dc.contributor.author Parthiban, G.
dc.contributor.author Banaulikar, S.
dc.contributor.author Sarkar, S.
dc.date.accessioned 2008-02-22T05:30:10Z
dc.date.available 2008-02-22T05:30:10Z
dc.date.issued 2005
dc.identifier.citation Marine georesources and geotechnology, Vol.23; 373-400p.
dc.identifier.uri http://drs.nio.org/drs/handle/2264/936
dc.description.abstract In view of the role of sediment geochemistry in regulating the benthic ecosystem, diagenetic remobilization of dissolved constituents, bottom water redox, and regeneration of benthic fluxes, surficial sediments in and around the track disturbed by a 'benthic disturber' were studied for metal variation in three phases: (1) before the disturbance, (2) immediately after the disturbance, and (3) during monitoring of restoration after approx. 44 months, from the same locations. Minor variations in metal concentrations before the disturbance were noticed indicating the homogeneity in the area or supply from similar source areas. Terrigenous fraction determined normatively from titanium contents in these sediments ranges between 40 and 47%. Most of the elements analyzed showed reduced average concentrations immediately after the disturbance suggesting physical removal and resedimentation in other areas with the migration of the plume. All the elements showed positive relation and coherence in the sediments collected after the disturbance, irrespective of their susceptibility to changes in provenance and depositional environment, whereas elemental associations during the predisturbance and monitoring periods can be explained by the known geochemical processes. The changes in Al, Ti, excess aluminium contents, their interelement relations, and factor analyses, suggest the possible transformation of clay mineral type due to the benthic disturbance that would involve changes in surface chemistry of clays. Interelement relations among redox-sensitive elements have also changed with time. This includes decoupling of Co from Mn after 44 months, probably due to the varying oxidation kinetics of two major oxides, Fe and Mn. Model calculations suggest increased diagenetic remobilization rates of Mn during the monitoring phase. Substantial increase in redox-sensitive elements, especially Fe and Mn indicate oxygenation of bottom.
dc.language.iso en
dc.publisher Taylor and Francis
dc.rights Copyright [2005]. It is tried to respect the rights of the copyright holders to the best of the knowledge. If it is brought to our notice by copyright holder that the rights are voilated then the item would be withdrawn.
dc.subject deep water
dc.subject sediments
dc.subject geochemistry
dc.subject ferromanganese nodules
dc.subject deep-sea mining
dc.subject environmental impact
dc.subject metals
dc.subject ecosystem disturbance
dc.title Alterations in geochemical associations in artificially disturbed deep-sea sediments
dc.type Journal Article


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