Change in direction of stress field in Kashan fault zone during Neogene, Middle part of Urumieh-Dokhtar Magmatic Arc.

The Kashan fault zone is located 30 km Southeast of Kashan with strike NW-SE and 80 km lengt that propagated in the middle part of Urumieh-Dokhtar magmatic arc. This fault zone intersects Eocene-volcanic intrusive, Oligocene conglomerates, Oligo-Miocene carbonate masses, Neogene and Quaternary sedimentary Units. In this research, reconstruction of paleo and neo-stress and structural evolution of Kashan fault zone has been assessed.  The collected structural data indicates the NW-SE trend and right-lateral transpression for main Kashan fault as the main fault zone in the region. The result of paleo-stress inversion and collected structural data indicate that after likely Middle Miocene (ca. Upper Miocene) the regional stress regime has been changed in which the direction of the maximum compression changed from NE-SW to N-S. The new N-S directed maximum compression caused the propagation of the E-W trending folds of the Neogene sediments and right-lateral kinematics of Kashan fault zone in the area. Furthermore, new N-S directed maximum compression formed the N-S trending grabens that have been filled by Pliocene and Quaternary detrital deposits.