R8: Metamorphic rocks and tectonics

[R8P-07] Structural architecture of an Archean collision zone; Insights from the Gadag-Mandya Shear Zone (GMSZ) and associated schist belts, Dharwar Craton, southern India

*Sreehari Lakshmanan¹, Tsuyoshi Toyoshima², Yoshihiro Nakamura³, Satish-Kumar Madhusoodhan², Sajeev Krishnan⁴ (1. Shimane U, 2. Niigata U, 3. AIST, 4. IISc)

Keywords:Archean, Mylonite, Collision tectonics, Fold-and-thrust belt, failed rift

We investigated the structural evolution of the Gadag–Mandya Shear Zone (GMSZ) and surrounding schist belts in the Dharwar Craton, southern India. The GMSZ is a ~250 km long deformation zone with a maximum width of ~1.5km. Shear sense indications show D2 reverse fault with top to NE or SW sense of movement, D3 and D4 strike-slip faults with a sinistral and dextral sense of movement. The GMSZ and associated schist belts represent a fold-and-thrust belt in connection with the inversion of failed rifts. This work implies that GMSZ does not represent a suture zone/plate boundary.