On the nature of the calcareous substrate of a ferromanganese crust from the Vityaz Fracture Zone, Central Indian Ridge: Inferences on palaeoceanography
DRS at CSIR-National Institute of Oceanography
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Title |
On the nature of the calcareous substrate of a ferromanganese crust from the Vityaz Fracture Zone, Central Indian Ridge: Inferences on palaeoceanography
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Creator |
Guptha, M.V.S.
Banerjee, R. Mergulhao, L. |
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Subject |
ferromanganese nodules
carbonate sediments substrata nannoplankton biostratigraphy palaeoceanography |
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Description |
A 15-cm-thick carbonate substrate encrusted with ferromanganese oxides from the Vityaz Fracture Zone, Central Indian Ridge was analysed to reconstruct the palaeoceanography of the region. Based on the calcareous nannoplankton assemblage, an early Pliocene age has been assigned to the calcareous substrate. Among the nannoplankton, discoasters outnumber coccoliths and show signs of dissolution. The presence of certain species of benthic Foraminifera such as Uvigerina, Lenticulina, Bulimina and Bolivina, indicates the infringement of the oxygen minimum zone during the deposition of the carbonates. The occurrence of a Reticulofenestra pseudoumbilica zone of early Pliocene age suggests a change in depositional conditions coinciding with the time of formation of the large depositional hiatuses documented in sediment cores from adjacent basins of the western Indian Ocean. These hiatuses resulted from the prevalence of intermediate subsurface currents such as the Somali Current or the Western Boundary Current
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Date |
2008-08-11T07:59:09Z
2008-08-11T07:59:09Z 2002 |
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Type |
Journal Article
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Identifier |
Geo-Marine Letters, Vol. 22(1); 12-18p.
http://drs.nio.org/drs/handle/2264/1434 |
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Language |
en
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Rights |
Springer
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Publisher |
Springer
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