Influence of rift geometry over successive post-rift sedimentation: Tectonostratigraphy of the eastern Kopeh Dagh Belt (NE Iran)

Abstract

Well, seismic (2D and 3D) and AHe age data, complemented by field surveys, were analyzed with the objective of investigating the tectono-stratigraphic evolution of syn- and post-rift sedimentary basins in the eastern Kopeh Dagh Belt (NE Iran), a region well known for its important oil and gas occurrences. The study was focused on evaluating how and when the geometry of syn-rift structures influenced the development of the post-rift sedimentation. Our results show that the Middle Jurassic rifting stage influenced the geometry of the post-rift basins. Carbonate buildup of the Upper Jurassic (Mozduran reservoir) was formed in the low relief accommodation zones between the Middle Jurassic opposing half-grabens in parallel to the sedimentation of argillaceous carbonates within the adjacent troughs. This geometry was also transmitted to the Lower Cretaceous, affecting the deposition of a relevant siliciclastic system (Shurijeh reservoir). The role of rifting was crucial in the distribution of reservoir facies and the generation of the structural-stratigraphic traps in the study area, which were also affected by late tectonic inversion. Uplift and denudation is likely to have occurred up to Late Miocene.