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

S. H. Jafri ¹, Ramavati Saxena ¹

Affiliations
1 National Geophysical Research Institute, Hyderabad 500007, IN

Abstract

Geochemical data is presented of an anorthosite dyke from Nuggihalli made of calcic plagioclase (An_70-80), amphibole, pyroxene and accessories like magnetite, sphene and apatite. The chemical data shows high Mg/Mg+Fe⁺⁺ ratio (Avg.=0.48) and CaO/Na₂O ratio (Avg.=8.70) with, <5 ppm Rb and 56-90 ppm Sr., indicating a substantial fractionation of ferromagnesium phase from a highly calcic ultrabasic parent magma.

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