Magmatic Epidote in the Neoarchaean Granitoids of Srinivaspura Area of Eastern Dharwar Craton and its Significance on Emplacement Mechanism of Granitoids

Magmatic epidote (mEp) in calc-alkaline, high-Mg granite is distinguished on the basis of euhedral crystals with allanite core and embayed contact, 'pistacite' components (25-32) and very low TiO₂ (<0.02%) content. Non-magmatic epidote occurs in association with biotite and chlorite, amphibole, magnetite and titanite and contains either <0.2% TiO₂ or <25% Ps. Consideration of stability of magmatic epidote under different fO₂ and dissolution characteristic against quartzofeldspathic material suggest that these granitoids are emplaced at a faster rate to low-pressure upper crustal region under high fO₂ condition by dyking.