Contributions to Mineralogy and Petrology

, Volume 27, Issue 3, pp 239–243 | Cite as

Phase relations in three charnockites from Pallavaram-Tambaram

  • S. K. Sen
  • J. R. Sahu


Chemical data on eight ferromagnesian silicates from a syenitic and two tonalitic charnockites from the type area near Madras show remarkably regular cation fractionation patterns. The distribution coefficients for magnesium-iron point to equilibration under granulite facies metamorphism. Orthopyroxene-garnet-biotite subsystem has been found to be of a near invariant nature, while the compositions of orthopyroxene and biotite in the nongarnetiferous tonalite are different. Analysis of phase equilibrium by Thompson type AFM projection strongly indicates that pressure, temperature and the chemical potential of water were constant for assemblages separated by large distances.


Silicate Fractionation Phase Equilibrium Mineral Resource Large Distance 
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Copyright information

© Springer-Verlag 1970

Authors and Affiliations

  • S. K. Sen
    • 1
    • 2
  • J. R. Sahu
    • 1
    • 2
  1. 1.Department of Geology and GeophysicsIndian Institute of TechnologyKharagpurIndia
  2. 2.Regional Research LaboratoryBhubaneswarIndia

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