Study of Joints on the North Eshtehard Fault Related Folding

The outcrop of northern part of North Eshtehard Thrust has been ed for study of structural evolution and geological processes. The study area includes folding structures with different scales regional to outcrop which belong to fault related folding category. Analysis of joints in the region among upper red formation strata shows two main sets which are usually tensional (j1 & j2). These joints are visible in sandstone units of upper red formation and most of them are filled with gypsum. It is obvious that the j1 joints are younger than j2. j1 and j2 joints are related to folding processes. The local stress field which could be measured the joint study is σ1=337/75, σ2=189/13 and σ3=077/03 and corresponds with the given paleostress direction for southern part of central Alborz.