ROCK JOINTS ANALYSIS TO DETERMINE THE MAIN STRESS FIELD IN BUSTANAH STRUCTURE NORTHEAST OF IRAQ
Joints are among the most widespread geologic structures as they are found in most each exposure of rock. They differ greatly in appearance, dimensions, and arrangement, besides they occur in quite different tectonic environments. This study is important because joints provide evidence on what kind of stress produced them (history of deformation) and also because they change the characteristics of the rocks in which they occur. The Measured data of joints from the studied area which are located in the high folded zone – Northeast of Iraq, were classified according to their relationship with the tectonic axes by projecting them stereographically using Schmidt net in GEOrient ver.9.5.0 software. The joint systems revealed the orientation of the major stress field that caused the area deformation. Two dominant joint systems were found in most stations of the studied area, which are hko>a (first place) and hko>b (second place). The main stress field direction from the joint’s classification is North East – South West which coincides with the opening of the red sea and the collision between Arabian and Iranian tectonic plates. The North West direction (which comes in the second place) it might be due to the rotational movement (counterclockwise) of the Arabian plate in addition to the effect of local stress in the area.