Structural Study of the Orogen-Transverse Jatni-Dhauli Fault and its Tectonic Implications on the Evolution of the Eastern Ghats Mobile Belt, Odisha, India

The Mesoproterozoic Eastern Ghats Mobile Belt (EGMB) is cross-cut by the Paikamal-Mahanadi-Dhauli transverse shear zone/fault, which has been studied along the Jatni-Dhauli sector, with respect to shear kinematics, vorticity, and tectonic implications. The Jatni-Dhauli area is represented by granulite facies of rocks that have undergone seven stages of deformation. The D1 to D4 deformations produced respective folds. The shear zones represent the D5 deformation. The Jatni-Dhauli shear zone has a WNW-ESE strike and shows dextral shear kinematics. Vorticity estimation indicates that the shear zone is dominated by transtensional strain. Transtension created the D6 normal faults that were superimposed on the ductile structures. The latest deformation, D7, developed conjugate strike-slip faults showing NNW-SSE directed compressive stress. The northern margin of the EGMB with the Singhbhum Craton is marked by multiple WNW-ESE-trending shear zones parallel with the Paikamal-Mahanadi-Dhauli shear zone, namely Riamal-Kamakhyanagar and Barakot shear zones, which are genetically linked to the western terrane margin thrust of the EGMB. The shear zones have not only undergone transtensional strain, but their en echelon arrangement also created transtension in the intervening blocks, which led to the formation of the Mahanadi rift valley. Further, dextral shearing along the transverse shear zone system created the orogenic flexure on the NW part of the EGMB and in the Singhbhum Craton. The extension of the Paikamal-Mahanadi-Dhauli shear zone into East Antarctica needs further study to strengthen the correlation between the Eastern Ghats Mobile Belt and Rayner Complex.