Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

A. Bhattacharya ¹, A. C. Mazumdar ¹

Affiliations
1 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur 721 302, IN

Abstract

A geobarometer based on the equilibrium Mg₃Al₂Si₃O₁₂ + 2Al₂SiO₅ (sillimanite) = 3MgAl₂O₄+5SiO₂ has been proposed. The geobarometric expression can be stated as P(bar)=9.68 T - 7106 + 10.307 T In (a^garnet_Mg3Al2Si3O12)^1/3/(a^spinel_MgAl2O4). Application of the proposed geobarometric formulation to some metapelites indicates that it registers reasonable pressure values which are in good agreement with the recommended pressure values for different terranes.

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