Carbon isotope studies of auriferous quartz carbonate veins from two orogenic gold deposits from the Neoarchean Chitradurga schist belt, Dharwar craton, India: Evidence for mantle/magmatic source of auriferous fluid
DSpace at IIT Bombay
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Title |
Carbon isotope studies of auriferous quartz carbonate veins from two orogenic gold deposits from the Neoarchean Chitradurga schist belt, Dharwar craton, India: Evidence for mantle/magmatic source of auriferous fluid
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Creator |
SARANGI, S
SARKAR, A SRINIVASAN, R PATEL, SC |
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Subject |
Carbon isotopes
Oxygen isotopes Archaean Orogenic gold deposits Dharwar craton Southern India MANTLE-DERIVED FLUIDS SOUTH-INDIA GREENSTONE-BELT CONTACT-METAMORPHISM ORE-DEPOSITS SHEAR ZONE MINERALIZATION GEOCHEMISTRY KARNATAKA PROVINCE |
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Description |
Carbon and oxygen isotopic compositions of carbonates from auriferous quartz carbonate veins (QCVs) of two orogenic gold deposits - Aijanahalli and Guddadarangavvana Halli (G.R. Halli) - from the Neoarchean Chitradurga schist belt of the Dharwar craton, southern India are examined to understand the origin of the mineralizing fluids. The average carbonate carbon (delta C-13(pdb)) and oxygen (delta O-18(smow)) isotope compositions of QCVs of Ajjanahalli are -5.5 +/- 1.3 parts per thousand and 14.1 +/- 2.7 parts per thousand, respectively. The same ratios for the QCVs of G.R. Halli are -6.2 +/- 1.9 parts per thousand and 14.1 +/- 0.5 parts per thousand. The corresponding average fluid delta C-13 and delta O-18 compositions are -5.81 +/- 1.14 parts per thousand, 13.78 +/- 5.1 parts per thousand. for Ajjanahalli and -4.64 +/- 0.7 parts per thousand, -6.50 +/- 0.6 parts per thousand for G.R. Halli. The delta C-13(pdb) of syn-sedimentary carbonates of BIF of Ajjanahalli (-1.8 +/- 0.1 parts per thousand), carbonated metabasalts of Ajjanahalli (-1.4 parts per thousand) and G.R. Halli (-1.3 parts per thousand) fall in the compositional range of marine carbonates (0 +/- 2 parts per thousand). As dissolution/decarbonation reactions during metamorphism of pre-existing carbonate/carbonated rocks produce CO2 with delta C-13 values similar to or more enriched than parent rock, the carbonate or fluid delta C-13 ratios of the QCVs (which fall in the compositional range of mantle/magmatic derived CO2 or carbonates) obtained in this work cannot be the result of metamorphism. It is proposed that gold mineralizing fluids were derived from juvenile magmatic melts and were channeled through crustal scale shear zones to give rise to the gold deposits. (C) 2012 Elsevier Ltd. All rights reserved.
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Publisher |
PERGAMON-ELSEVIER SCIENCE LTD
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Date |
2014-10-15T10:27:29Z
2014-10-15T10:27:29Z 2012 |
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Type |
Article
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Identifier |
JOURNAL OF ASIAN EARTH SCIENCES, 521-11
http://dx.doi.org/10.1016/j.jseaes.2012.02.004 http://dspace.library.iitb.ac.in/jspui/handle/100/14744 |
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Language |
en
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