Nongchram Fault: A Major Dislocation Zone from Western Megbalaya

Abstract

A zone of fault breccia. gouge, silicification and rare mylonite reveals the presence of a 20 km long north-south trending tensional fault in the granitoid-gneiss terrain of Western Meghalaya. Emplacement of alkaline magmatic rocks including carbonatite, in the form of thin dykes along the fault and associated fractures in the vicinity, indicate deep seated nature of the dislocation. Changes in the drainage pattern in recent past and high microseismicity along the fault zone provide evidences of recent reactivation.