The Stratigraphy and Structure of the Sittampundi Complex, Tamil Nadu, India

The Sittampundi Complex has the following igneous stratigraphy from the bottom upwards: gabbro with pyroxenite inclusions, chromite-layered hornblende anorthosite and clinozoisite anorthosite. This stratigraphy is only well preserved in the north-east of the area. The complex has been folded into an isoclinal antiform with the result that the stratigraphy is duplicated in two fold limbs which are locally separated by gneiss. A second phase of open folding has given rise to the present form of the complex as a major interference pattern. Linear mineral fabrics largely formed in association with the first deformation. The complex is a tectonic remnant of a layered igneous body that has been recrystallized and deformed. It is remarkably well preserved in more ductile, quartzo-feIdspathic gneisses that have suffered higher finite strain.