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Hydrovolcanic activity in the Central Indian Ocean Basin. Does nature mimic laboratory experiments?

DRS at CSIR-National Institute of Oceanography

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Title Hydrovolcanic activity in the Central Indian Ocean Basin. Does nature mimic laboratory experiments?
 
Creator Iyer, S.D.
ShyamPrasad, M.
Gupta, S.M.
Charan, S.N.
Mukherjee, A.D.
 
Subject volcanic rocks
magnetite
seamounts
sand
authigenic minerals
 
Description Classical works in the 1960's on spherules (volcanic, extraterrestrial, cosmic etc.) were carried out in order to distinguish these morphological and compositionally so as to understand their genesis yet, in some cases their origin has remained enigmatic and indeterminate. We present here the finding of volcanic magnetite spherules up to 475 mu m in diameter which were recovered from the base of a seamount (basement age approx 50 Ma) in the Central Indian Ocean Basin (CIOB). The spherules have quenched and crystalline textures, analogous to cosmic ones but compositionally are Fe-enriched (avg. 74%) together with other magmaphile elements. A distinctive lack of a Ni core is noted vis-a-vis Si-enriched areas. The spherules are very similar to those experimentally produced by simulated hydrovolcanic activity involving intereaction of a thermite melt with water-saturated quartzo-feldsphathic sand. Our finding seem to indicate such a process to have occurred in nature at abyssal depth. The plausible mechanism we conceive is the reaction of Fe-rich lavas or hydrothermal emanations with the abundant surrounding siliceous ooze which the dominant sediment type in the basin. We regard this is as the first report of an authentic proof for hydrovolcanism at oceanic depth of 5200 m, which probably occurred approx 10 ka ago as suggested by the associated radiolarian species
 
Date 2009-01-12T09:18:25Z
2009-01-12T09:18:25Z
1997
 
Type Journal Article
 
Identifier Journal of Volcanology and Geothermal Research, Vol.78; 209-220p.
http://drs.nio.org/drs/handle/2264/2057
 
Language en
 
Rights Copyright [1997]. 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 Elsevier