Neogene provenance evolution of the Zagros foreland basin: Implication for the uplift and outward growth history of the Zagros orogenic belt, Iran

Abstract The Arabia-Eurasia convergence led to the uplift of the Zagros orogenic belt and the outward propagation of the fold-and-thrust system. In this paper we focus on the Miocene strata in southwestern Iran to study the stratigraphic chronology, basin evolution, and uplift history of the Iranian Plateau. Our magnetostratigraphic results enable the establishment of a time scale ranging from 14 Ma to 10 Ma. Petrographic data of sandstones indicate a remarkable change in the provenance of the sediments from feldspar sandstone to lithic-dominated sandstone beginning at 13 Ma. The U-Pb ages of detrital zircons also demonstrate a dramatic shift at 13 Ma. Based on these new data, we discuss the uplift and denudation processes of the Zagros orogenic belt. During the late Oligocene to early Miocene (25–17 Ma), what is now the Iranian Plateau was mainly occupied by a vast epicontinental sea, and both the Urumieh-Dokhtar Magmatic Arc and the Sanandaj-Sirjan Zone underwent some uplift due to the initial Arabia-Eurasia collision. During the middle Miocene (17–13 Ma), the source material was mainly eroded from the uplifted Sanandaj-Sirjan Zone (SSZ), whereas the High Zagros had only experienced some uplift but with limited height and thus could not have provided a large amount of source material to the foreland basin. After 13 Ma, the High Zagros underwent accelerated uplift and became a new source region for the infill of the foreland basin. In this study, we provide new evidence for the uplift and denudation history of the SSZ and High Zagros during the Neogene.