Compressional and Extensional Tectonic Phases in Safeen, Bana Bawi, and Haibat Sultan anticlines NE Iraq, determined from Microtectonic Elements

Abstract

The study area includes parts of the High Folded and Foothill Zones of Northeast Iraq. A series of intense folding namely Safeen anticline in the High Folded, Bana-Bawi, and Haibat Sultan anticlines in the Foothill zone. The fold axes trend in northwest-southeast direction present structural analysis; it is concluded that the study area is affected by four tectonic phases. Two of the compressional while the other two are extensive phases, both of them phases perpendicular in fold axes lie in i.e NE – SW direction or parallel to fold axes lie in i.e NW – SE direction. The first compressive phase corresponds with systems hOl-a & hkO-a, with reverse faults striking NW-SE and strike-slip fault enclosing angles larger than 45° with the folds axes. This phase was followed by extensive tectonic phase as releasing phase, which corresponding with the normal faults directed NW-SE and hOl-c shear joints. The region was then affected by second compressive phase corresponding with reverse faults striking NE-SW, strike-slip faults enclosing angles smaller than 45° with the folds axes and Okl-b & hkO-b shear joints systems Okl-b & hkO-b. Lastly the region has been affected by second extensive phase corresponding with shear joints system and NE-SW striking normal faults. Also tension joints ac, bc, and ab were studied in these study results were ac joints correspond with the first compressive phase direction of that caused Zagros folds in Iraq, and bc joints correspond first extensive releasing phase.