Records of the Geological Survey of India, Volume 75, Issue 15

acid charnockite acid plagioclase acid types aggregates alkalies alkaline magma alteration alumina amphibole amphibolites apatite aplitic associated basic charnockite basic plagioclase biotite calcium Calcutta Charnockite Series colour composition constituents cordierite corresponding to sp crystallisation Damar Dongri derived from diopside diopside and hypersthene eclogitic eclogitic rocks exposures felspars ferruginous quartzites formation formed fresh plagioclase garnet garnet G Geological Survey give rise gneisses gneissic banding granitic granitic magma granodioritic granular granulitic greenish grünerite hornblende hyper hypersthene Hy igneous INTERMEDIATE CHARNOCKITE iron-ore Jeypore labradorite latter leucocratic LXXV M. S. Krishnan magma marginally microscope mixed gneisses occur origin orthoclase P. K. Ghosh plagioclase Plate pleochroism Potash felspar present primary plagioclase Professional Paper pyroxenes quartz quartzites reaction regional metamorphism secondary after diopside secondary minerals secondary plagioclase sediments sheet SiO2 slide small crystals sodic sometimes specimen spinel sthene sub-acid Survey of India texture tion ultrabasic ultrabasic charnockites variety vide Pl yellow-green hornblende