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Formation of hydrothermal deposits at Kings Triple Junction, northern Lau back-arc basin, SW Pacific: The geochemical perspectives

DRS at CSIR-National Institute of Oceanography

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Title Formation of hydrothermal deposits at Kings Triple Junction, northern Lau back-arc basin, SW Pacific: The geochemical perspectives
 
Creator Paropkari, A.L.
Ray, D.
Balaram, V.
Prakash, L.S.
Mirza, I.H.
Satyanarayana, M.
Rao, T.G.
Kaisary, S.
 
Subject Hydrothermal Field
Lau basin
Mineralogy
hydrothermal deposits
 
Description An inactive hydrothermal field was discovered near Kings Triple Junction (KTJ) in northern Lau back-arc basin during 19th cruise of R/V Akademik Mstislav Keldysh in 1990. The field consisted of a large elongated basal platform ‘the pedestal’ with several ‘small’ chimneys on its periphery and one ‘main mound’ superposed over it. The surrounding region is carpeted with lava pillows having ferromanganese ‘precipitate’ as infillings. The adjoining second field consisted of small chimney like growths termed as ‘Christmas Tree’ Field. The basal pedestal, the peripheral chimneys and small ‘Christmas Tree’ like growths (samples collected by MIR submersibles), though parts of the same hydrothermal field differ significantly in their mineralogy and elemental composition indicating different history of formation. The pedestal slab consisting of chalcopyrite and pyrite as major minerals and rich in Cu is likely to have formed at higher temperatures than sphalerite dominated peripheral chimney. Extremely low concentration of high field strength elements (e.g. Zr, Hf, Nb and Ta) and enrichment of light REE in these sulfides indicate prominent influence of aqueous arc-magma, rich in subduction components. The oxide growths in the 'Christmas Tree' Field have two distinct layers, Fe rich orange-red basal part which seems to have formed at very low temperature as precipitates from diffused hydrothermal flows from the seafloor whereas Mn rich black surface coating is formed from hydrothermal fluids emanated from the seafloor during another episode of hydrothermal activity. Perhaps this is for the first time such unique hydrothermal oxide growths are being reported in association with hydrothermal system. Here, we discuss the possible processes responsible for the formation of these different hydrothermal deposits based on their mineralogy and geochemistry.
 
Date 2010-03-09T06:04:06Z
2010-03-09T06:04:06Z
2010
 
Type Journal Article
 
Identifier Journal of Asian Earth Sciences, vol.38(3-4); 121-130
http://drs.nio.org/drs/handle/2264/3558
 
Language en
 
Rights An edited version of this paper was published by Elsevier. Copyright [2010] Elsevier. 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