Structural analysis of T. Sundupalle greenstone belt and surrounding granitoids, Andhra Pradesh, India

This contribution highlights the less widely known T. Sundupalle greenstone belt and surrounding granite–gneiss complexes. The greenstone belt trends NNW and comprises supracrustal assemblages with intense deformation. Four episodes of deformation events are revealed from this present structural study. Younger deformation episodes like igneous intrusions, recrystallization, and partial melting complicates the older fabric elements. Several deformation episodes were recognized by a systematic structural analysis based on superposed fabrics and principle of cross-cutting relationships. However, due to superposed deformation, often the features become obscure. The identification of the deformation episodes through the fabric elements in the shear zone allowed a tectonic interpretation. The initial greenstone belt formation above the thin hot Archaean crust followed by sinking and partial melting to form granitoids and their lit-per-lit emplacement along foliations formed gneissosity and further deformation, folding, and partial remelting generated migmatitic gneiss. The youngest event is the dyke emplacement along different trends during extensional tectonic regime.