Determination of paleo-stress based on the study of discontinuities and folds in Zagros Collision Zone Case Study of Kermanshah Region
سپیده رضابیک
1
(
)
عبدالله سعیدی
2
(
)
Mehran Aryan
3
(
)
علی سربی
4
(
)
Keywords: Stress, Conjugate faults, Slip fault analysis Multiple Inverse Method, Folds, Kermanshah.,
Abstract :
The studied zone is in the Northern part of Zagros Suture Zone (Kermanshah) the existance deep sea sediments, oceanic crust remnants, platform carbonates, igneous and metamorphosed rock of active margin and carbonate sequence of passive margin that are assembled in the studied area show a tectonical pressure system from the late Cretaceous up to now . This convergent area has provided a very complicated structural zone. This convergent area has provided a very complicated structural zone. The main purpose of this study is stress characteristic analysis in Zagros Suture Zone (Kermanshah).To recognize and study the arrangement of stress axes a great amount of data has been gathered from the folds axial surface and the faults which are appeared within the rocks specially the radiolaritic rocks. The data includes characteristics of fault surface geometry, fault slip and lineation slip. The stress recording patterns for data in this study is Multiple Inverse Method and comparison with stress position by using folds axial surface. By studing folds we obtained the situation of main stress σ1, σ2 and σ3 respectively is 029, 127, 234and by using the method Multiple Inverse Method, the situation of main stress is obtained 059, 304, 194. Based on the investigations in the study area and measurements on Cretaceous rocks, the results show that the main stress direction since Cretaceous up to now is northeastern with minor changes. The estimations of stress direction were the same in both cracks and faults. As a result, the shortening direction has been constant, so the shortening faults all show one direction of stress.