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Dating of the 85 degrees E Ridge (northeastern Indian Ocean) using marine magnetic anomalies

DRS at CSIR-National Institute of Oceanography

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Title Dating of the 85 degrees E Ridge (northeastern Indian Ocean) using marine magnetic anomalies
 
Creator Michael, L.
Krishna, K.S.
 
Subject magnetic anomalies
gravity anomalies
oceanic crust
geomagnetic polarity
Mahanadi Basin
 
Description The 85 degrees E Ridge is a typical aseismic ridge in the northeastern Indian Ocean in view of the fact that it associates with exceptional gravity and magnetic signatures. The ridge possesses two different gravity anomalies: the north part (up to 5 degrees N latitude) is associated with negative gravity anomaly, whereas the south part coincides with positive gravity anomaly. In contrast to this, the ridge consists of alternate streaks of positive and negative magnetic signatures distributed for asymmetrical extents. With the consideration of ridge seismic structure and geomagnetic polarity reversals, we modelled both positive and negative magnetic anomalies of the ridge. This shows that the 85 degrees E Ridge was formed during the period of rapid changes in the Earth’s magnetic field, earlier to that, the underlying oceanic crust was created in the Cretaceous superlong normal polarity phase. The results further reveal that the positive and negative magnetic signatures of the ridge have been created, in general, by a relief of the ridge and polarity contrast between the ridge material and adjacent oceanic crust, respectively. On correlation of the ridge’s magnetization pattern to the geomagnetic polarity timescale, we believe that the 85 degrees E Ridge volcanism started at anomaly 33r time (approx. 80 Ma) in the Mahanadi Basin by a short-lived hotspot, thereafter the process continued towards south and finally ended at approx. 55 Ma in the vicinity of the Afanasy Nikitin Seamount.
 
Date 2011-06-15T12:05:56Z
2011-06-15T12:05:56Z
2011
 
Type Journal Article
 
Identifier Curr. Sci., vol.100(9); 2011; 1314-1322
http://drs.nio.org/drs/handle/2264/3853
 
Language en
 
Rights Copyright [2011]. 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.
 
Publisher Current Science Association