STRUCTURAL AND TEXTURAL CHARACTERISTIC OF SYENITE INTRUSIONS FROM PAKKANADU AND PIKKILI ALKALINE SYENITE COMPLEX TAMILNADU SOUTH INDIA

Abstract

The Syenite were formed during the Late Proterozoic in the northern part of South India and show similarity to the Alkaline-Carbonate-Ultramafic Complex of Pakkanadu in South India and displays close relationship with a diverse group of Peninsular Gneissic complex. The isolated bodies of Syenite sporadically distributed in Salem and Dharmapuri districts of Tamil Nadu, correspond to the alkaline magmatism which were intruded into the country rock at Kamaneri, Chindamaniyur, Semmandapatty in Salem and Pikkili and around in Dharmapuri. The field settings and structural characteristics indicate these Syenite bodies must have formed from plutonic origin which was later intruded by dykes. Texturally Syenite is leucocratic, medium to coarse grain, equigranular alkaline rock showing hypidiomorphic texture and consisting of K-feldspar (microcline) pyroxene and amphibole with accessory minerals plagioclase feldspar, magnetite, sphene, zircon, calcite and apatite.