Petrochemistry of the Chengannoor Granite, Alleppey District, Kerala

Abstract

The granite of Chengannoor, Alleppey district, Kerala, having an intrusive relationship with Precambrian charnockite-cordierite gneiss sequence is inferred to be a post-kinematic granite of magmatic origin. The major mineral constituents are mesoperthitic K-feldspar with quartz and two generations of plagioclase. A late/post intrusive potash metasomatism caused changes in the mineralogy and chemical composition of the granite.

Recent K-Ar dating of hornblende from the Chengannoor granite assigns an age of 550 m.y. for the granite (Soman, Golubyev and Santosh. Ind. Jour, Earth Science) (in press).