Fold amplification history unravelled from growth strata: the Dorood anticline, NW Persian Gulf

Abstract

Abstract: The origin and kinematic evolution of the Dorood growth anticline, a kilometre-scale fold located in the Iranian NW part of the Persian Gulf on the Zagros front, is discussed based on the geological interpretation of a seismic section and subsequent application of a number of techniques such as depth to detachment estimations, sequential cross-section restoration, estimations of crestal structural relief, shortening, wavelength and fold core area in various stages of fold amplification, and comparison between functions derived from the anticline analysis and functions for theoretical folds. Long-term fold growth rates indicate a slow amplification for c . 88.6 Ma punctuated by two periods of faster growth during the Late Cretaceous and from the Late Miocene to the present day. The kinematic evolution proposed involves vertical push related to reactivation of a basement fault during the oldest amplification event and fold tightening owing to buckling as a consequence of horizontal compression in the youngest event, both causing evaporite motion. Fold amplification took place by a combination of hinge migration and limb rotation.