Separation of Paleostresses Phases with Inversion Method of Fault Planes in the South of Birjand Region

Structural originating of the Southern Birjand Ophiolite Mélange is required to be an implementation of various stress phases in the evolution history of this region. Separation of different phases in the multiple inverse method shows that the maximum stress axis(σ1) in several position of this zone mainly has NE-SW to E-W trends and the minimum stress axis(σ3) NW-SE to N-S trends. By using obtained stress orientations and compiling them with the other obtained structural data such as extensional structures (normal faults and extensional fractures), compressional structures (thrust faults, lineation and foliation trends in flysch unites and the orientation of folds axes), shear-comperssional structures (fracture types in the crashed zones)and extensional structures (strike-slip faults with normal tensor, extensional and sigmoidal fractures), three stages i.e.comperssional, shear-compersional and extensional are concluded for paleotectonic of this region.