Structural Evolution of the Area North of Ajloun Dome, Jordan

The detailed mapping of the area north of Ajloun dome proved the existence of conglomerate beds (equivalent to Dana Conglomerate) of post Eocene (Post Umm Rijam). Other outcrops in the area range from Turonian to Miocene. The structures in the present study area consist of one Syncline (Ausara Syncline), a group of normal faults, one strike slip fault, and a group of systematic joint sets. The Ausara symmetric syncline is trending S65ºW, plunging 17º. It was formed during the second stage of the Syrian Arc Stress field (SAS), after the formation of Ajloun dome, which was formed in the Upper Cretaceous, during the first phase of the Syrian Arc folding. Normal faults, grabens and horsts trend NNW. They are parallel to the general Dead Sea Stress field (DSS) which trends NNW-SSE compression and ENE-WSW tension. They formed after the Ausara syncline because one of these fault truncated the syncline. Horizontal fault block rotation is indicated from the change in the general strike of the joint sets. The area close to the Jordan valley was tilting to the west as indicated from the general westward dipping of the Tertiary and the underlying Upper Cretaceous beds. The general structure of the area can be described as faulted flexure.