The eastern termination of the Zagros Fold-and-Thrust Belt, Iran: Structures, evolution, and relationships between salt plugs, folding, and faulting

摘要

The Zagros Mountains result from the ongoing collision between the Arabian and central Iran plates. The main features of the eastern Zagros are (1) numerous emerged or buried salt diapirs, made up of Late Precambrian Hormuz salt and (2) the irregular along-strike shape of the collision-related detachment folds with frequent bending. To understand this layout, four geological cross sections have been constructed from the Persian Gulf foreland basin to the inner part of the Zagros Fold-and-Thrust Belt. Shortening in the deformed parts of the sections is less than 10% and is mainly accommodated by detachment folding. We show that late Cenozoic folding occurred in a region that was already punctuated by salt domes and diapirs. In fact, almost continuous halokinesis developed since the earlier Paleozoic, i.e., just short time after the deposition of the Hormuz salt, and continued up to the Present. These preexisting salt structures and their relevant local thickening strongly influenced both the localization and the direction of folds.