NATURE OF CRATON-MOBILE BELT BOUNDARY: AN EXAMPLE FROM BASTAR CRATON-EASTERN GHATS MOBILE BELT CONTACT AROUND JAYPUR, ORISSA, INDIA

摘要

The Eastern Ghats mobile belt-Bastar craton contact around Jaypur, Orissa, is marked by the development of mylonites and shear zones, which involved components from both the adjoining belts. These shear zones are roughly parallel to the western margin of the Eastern Ghats belt. S-C fabrics in them indicate a relative downward movement of the Eastern Ghats rocks. The microstructures in this shear zone are indicative of ductile environment: high temperature and considerable depth. Notably, these boundary shear zones are developed early, during the downward movement of the Eastern Ghats belt. However, the westerly dipping shear plane could have been rotated towards the mobile belt at the late stage of collision.