Style and age of deformation in the NW Persian Gulf

The study area is located in the foreland and in the frontal part of the Zagros Range (Persian Gulf), which contains very large oil and gas fields. The data consist of two orthogonal sets of 2D seismic sections. Folds trending NNE–SSW and N–S (Arabian trend) and NW–SE (Zagros trend) are documented. These folds developed during two folding phases: an older Late Cretaceous phase and a younger Late Cenozoic one. Folds with N–S and NNE–SSW trends formed during the older phase. During the younger phase the older, deep-seated, NNE–SSW Arabian folds were reactivated and tightened. These folds affected beds younger than the Cretaceous, forming open folds with the Arabian trend. At the same time, other folds with the NW–SE Zagros trend developed and these have been active until recent. Some giant and super-giant oil and gas fields are found in broad Arabian-trending folds in the Zagros foreland. This paper demonstrates that the Arabian folds in the study area are due to folding during the Late Cretaceous and to additional folding during Late Cenozoic times.