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Morphological characteristics and emplacement mechanism of the seamounts in the Central Indian Ocean Basin

DRS at CSIR-National Institute of Oceanography

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Title Morphological characteristics and emplacement mechanism of the seamounts in the Central Indian Ocean Basin
 
Creator Das, P.
Iyer, S.D.
Kodagali, V.N.
 
Subject seamounts
fracture zones
seamount chains
tectonophysics
oceanic crust
geochemistry
 
Description The morphotectonic features of the Central Indian Ocean Basin (CIOB) provide information regarding the development of the basin. Multibeam mapping of the CIOB reveals presence of abundant isolated seamounts and seamount chains sub-parallel to each other and major fracture zones along 73 degrees E, 79 degrees E and 75 degrees 45' E. Morphological analyses were carried out for 200 seamounts that occur either as isolated edifies or along eight sub-parallel chains. The identified eight parallel seamount chains that trend almost north-south and reflecting the absolute motion of the Indian plate, probably originated from the ancient propagative fractures. Inspite of the differences in their height, the seamounts of these eight chains are morphologically correlatable. In the study area the seamounts are clustered north and south of 12 degrees S latitude. Interestingly, in the area north of 12 degrees S (area II: 9 degrees - 12 degrees S) the seamounts are distinctly smaller (less than equal to 400 m height) whereas, the area south of 12 degrees S (area I: 12 degrees - 15 degrees S) has a mixed population of seamounts. The normalized abundance of the CIOB seamount is 976 seamounts/106 km sup(2) but on a finer scale this value varies from 500 to 1600 seamounts/106 km sup(2), which is less than the seamount concentrations of the Pacific and Atlantic oceans (9000 to 16,000 seamounts/ 106 km sup (2)). Three categories of seamounts are present in the CIOB e.g. (1) single-peaked (2) multi-peaked and (3) composite. The study indicate that single-peaked seamounts are dominant (89%) while multi-peaked is less (8%) and composite ones are rare (3%) in the CIOB. The progressive northward movement of the Indian continent caused collision between India and Asia at around 62 Ma ago. A majority of the near-axis originated seamounts in the CIOB seemed to have formed as a consequence of the temporally widespread (Cretaceous ~65 Ma to late Eocene b49 Ma) collision between India and Eurasia. The regional stress patterns in the Indian plate vary N to NE in the continent and N to NW in Indian Ocean areas. The combined effect of the regional stress patterns maintained the orientation of the seamount chains and the local stress regime helped in the upwelling of magma and formation of seamounts. The low heat flow, morphological features and geochemical signature indicate that the morphotectonic structures formed contemporaneously with the oceanic crust.
 
Date 2008-01-31T07:46:35Z
2008-01-31T07:46:35Z
2007
 
Type Journal Article
 
Identifier Tectonophysics, Vol.443; 1-18p.
http://drs.nio.org/drs/handle/2264/763
 
Language en
 
Publisher Elsevier