Study of the relationship between fracture geometry and vein-style mineralization using paleostress analysis in the Garijgan shear zone, eastern Iran

The Garijgan area is located 25 km south of Khousf in South Khorasan province, between two strike-slip faults, and is actually a small classic non-parallel shear zone. The eastern border of this zone is a dextral strike-slip fault with a reverse component with an average dip of 65 degrees towards the northeast, and its western border is a dextral strike-slip fault with a reverse component with an average dip of 71 degrees towards the southwest. The paleostress analysis in the study area shows that the first action of the stress regime occurred during the Eocene in the form of strike-slip with a maximum axis of σ1= 058.04, and the second stage of stress in the Quaternary period took place in the form of strike-slip and transpression with a maximum axis of σ1=003.05. Therefore, the axis of maximum stress (σ1) from Eocene to Quaternary has rotated about 55 degrees counter-clockwise. By examining satellite images and preparing the map of the distribution of fractures and drawing a rose diagram and a histogram of fractures, they can be placed in three categories in the direction of NW-SE, NE-SW and E-W. The faults of the first group are more abundant and they have mineralization, but the other two groups have no mineralization. The main faults of the shear zone (Y) and the conjugate faults that have a lower angle with respect to the shear zone (R, P) have provided suitable conduits for the rise of silica-rich mineralized hydrothermal fluids.