Strain Analysis of Injana Formation at Durbendbazian Anticline /Northern Iraq

Abstract

Durbendbazian Anticline locates at the Southwestern city of Sulaymania about 50 Km. north of Iraq. The objective of the study is to identify the strain state in Injana Formation, which locates on southwestern limb of Durbendbazian Anticline, by using Fry method technique. The results of the study showed that the orientations of the shortest axis E3 is in NE -SW direction, while the orientations of the intermediate E2 and the longest E1 of strain ellipsoid axes are in parallel and inclined directions with the fold axis. The Results of Flinn diagram represented from strain ratios indicate that the strain ellipsoids have oblate shapes with (K- value) less than one. From this study, we can conclude that the studied area subjected after sedimentation of Injana Formation to biaxial negative strain by effect of two stress components. The first was in northeast-southwest direction caused by compression stress resulted from the oblique collision of Arabia and Eurasia as a major stress component affected perpendicular to the fold axis of Durbendbazian Anticline. Whereas the second one acted along the fold axis and resulted by stress component parallel with plate margin due to oblique collision of Arabian and Eurasian plates. The effect of the second stress component is evident in curving manner of the fold axis.