Charnockite 'in the Breaking': Evidences from the Trivandrum Region, South Kerala

Abstract

Field and microstructural evidences indicating retrogressive-transformation of banded charnockite to leptynite (garnet gneiss) through a transition zone of khondalite (garnet biotite gneiss) is reported from two localities in south Kerala. In the same localities, formation of acid charnockite patches are also noted. Structural analyses show that the breaking event post-dates the formation and isoclinal folding of banded charnockite, but clearly pre-dates the making of patchy charnockite.