4-D evolution of anticlines and implications for hydrocarbon exploration within the Zagros Fold-Thrust Belt, Kurdistan Region, Iraq

Abstract

The Zagros Fold-Thrust Belt, extending from southern Iran, through northern Iraq and into Turkey, is characterized by elongate NW-trending anticlines that house large hydrocarbon accumulations. In recent years, the Kurdistan region of northern Iraq has become an area of interest for both structural studies and petroleum exploration-related investigation. Key questions to be answered concern the nature of the anticlines and whether the geometry of any associated thrusts can be predicted from surface geomorphology, as well the 4-D evolution of the area and along-strike continuity of the anticlines. To address these questions, this study combines field data, remote-sensing data concerning the structure and geomorphology of the anticlines, and structural modeling in order to produce robust interpretations of the geometries of the reverse fault structures that core the majority of these anticlines. Results indicate that this methodology can be used to constrain potential thrust configurations at depth and the probable style of fold amplification and lateral propagation. In addition, this study shows that the growth of the anticlines can be considered in 4-D, with consideration given to the interaction of the Zagros-age deformation with the pre-existing basement fabric. We demonstrate that combining both structural and geomorphological methodologies can lead to a better understanding of the geometry and evolution of the trap-forming structures in the Kurdistan region of Iraq and thus is expected to be of interest to the petroleum industry.