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Low-density CO(2)-rich fluid inclusions from charnockites of southwestern Madurai Granulite Block, southern India; implications on graphite mineralization

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Title Low-density CO(2)-rich fluid inclusions from charnockites of southwestern Madurai Granulite Block, southern India; implications on graphite mineralization
 
Creator BAIJU, KR
NAMBIAR, CG
JADHAV, GN
KAGI, H
SATISH-KUMAR, M
 
Subject ultrahigh-temperature metamorphism
carbon-isotope
ortho-pyroxene
grade indicator
natural quartz
raman-spectra
lower crust
tamil-nadu
water-loss
co2
fluid inclusion
low density
graphite
metamorphism
madurai granulite block
 
Description Characterization of fluid inclusions in graphite-bearing charnockites from the southwestern part of the Madurai Granulite Block in southern India reveals a probable relation with the formation and break down of graphite during the high-grade metamorphism. The first-generation monophase pure CO(2) inclusions, the composition of which is confirmed by laser Raman spectroscopy, recorded moderate density (0.77-0.87 g/cc) corresponding to low tapping pressure (around 2 kb) than that of the peak granulite-facies metamorphism. The precipitation of graphite, as inferred from graphite inclusions and delta(13)C values of the graphite from the outcrops, is interpreted as the cause of this lowering of fluid density. An intermediate generation of pseudosecondary inclusions resulted from the re-equilibration or modification of the first-generation fluids and the CO(2). formed is interpreted to be the oxidation product from graphite. The youngest generation of fluids which caused widespread retrogression of the granulites is a low-temperature (similar to 350 degrees C) high-saline (32.4-52.0 wt% NaCl equivalent) brine. Carbon isotope data on the graphite from the charnockites show delta(13)C values ranging from -11.3 to -19.9 parts per thousand, suggesting a possibility of mixing of carbon sources, relating to earlier biogenic and later CO(2) fluid influx. Combining the information gathered from petrologic, fluid inclusion and carbon stable isotope data, we model the fluid evolution in the massive charnockites of the southwestern Madurai Granulite Block. (c) 2009
 
Publisher PERGAMON-ELSEVIER SCIENCE LTD
 
Date 2011-08-25T11:24:47Z
2011-12-26T12:57:03Z
2011-12-27T05:46:47Z
2011-08-25T11:24:47Z
2011-12-26T12:57:03Z
2011-12-27T05:46:47Z
2009
 
Type Article
 
Identifier JOURNAL OF ASIAN EARTH SCIENCES, 36(4-5), 332-340
1367-9120
http://dx.doi.org/10.1016/j.jseaes.2009.06.010
http://dspace.library.iitb.ac.in/xmlui/handle/10054/11007
http://hdl.handle.net/10054/11007
 
Language en