Myllium granitoids of Shillong plaeau:Myllium granitoids are characterised by the development of pink to white coloured phenocrysts.Microscopic studies reveal that the phenocrysts are mainly composed of prismatic grains of microcline and lath shaped plagioclase.Perthite occurs. Groundmass composition is characterised by quartz,microcline,plagioclase,muscovite and biotite.
In these granites have large phenocrysts of microcline and plagioclase are embedded in a groundmass of quartz and feldspar and mica representing porphyritic texture. In some places, vermicular intergrowth of quartz within plagioclase is depicting myrmekitic texture.Graphic texture is also present .Myllium granitiods on the basis of modal mineralogy occupy the field of granite and granodiorite in theQAP diagram.
Porphyritic granite of Kamakhya area.
Fine grained granites of Jirang -patharkhmah area.
In these granites have large phenocrysts of microcline and plagioclase are embedded in a groundmass of quartz and feldspar and mica representing porphyritic texture. In some places, vermicular intergrowth of quartz within plagioclase is depicting myrmekitic texture.Graphic texture is also present .Myllium granitiods on the basis of modal mineralogy occupy the field of granite and granodiorite in theQAP diagram.
Porphyritic granite of Kamakhya area.
Fine grained granites of Jirang -patharkhmah area.
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