The Oligocene to Lower Miocene depositional sequences of the Zagros Basin, SW Iran

Abstract

This research assesses the Oligocene to Lower Miocene Asmari and Pabdeh formations characteristics and depositional sequences in the Zagros Basin (south‐west Iran). A regional stratigraphic transect is selected including the Persian Gulf Foreland Basin, Dezful Embayment, and the Zagros Simple Folded sub‐zones of the Zagros Basin. Five major depositional sequences have been distinguished by major changes in facies and stratal architecture. The spatial and temporal distribution and evolution of the five third‐order sequences identified show a strong progradation system from the Zagros Simple Folded Belt (N/NE) towards the Persian Gulf Foreland Basin, especially during the Rupelian, while geometric intricacy and significant facies changes are less developed in the Late Chattian and Early Miocene. According to the sequence stratigraphy correlation, two tectonic pulses are proposed for the Asmari deposits in the Dezful Embayment and Zagros Simple Folded Belt during the Rupelian to Early Chattian. During the Burdigalian, the series drastically thickens northward, so that the greatest sediment thickness occurred in the Zagros Simple Folded Belt. There is probably a connection between the structural closure of the Neo‐Tethys and the continuous uplift of the Zagros fold belt in the study area.