Mineral Ages of Pegmatites from the Palghat Gap Region in Kerala and Their Tectonic Significance

Of the three styles of deformation recognised in the Palghat Gap area, the D₃ period is conspicuous with a major pegmatite emplacement phase, associated with the migmatization event. Dating of mica from pegmatites belonging to this stage (both concordant and cross-cutting) has yielded ages ranging from 484 to 512 m.y. The pegmatite emplacement is suggested to be towards the closing stage of a retrogressive metamorphic event, associated with crustal uplift in the Palghat Gap region, which laid the tectonic frame-work for the formation of the gap later.