The stepwise closure of the Tethyan Seaway in the Burdigalian (Early Miocene): A multiproxy sequence stratigraphic approach (Qom Basin, Iran)

This study analyses the closure history of the Tethyan Seaway, connecting the Tethys and the Indian Ocean, during the Early Miocene as recorded in Central Iran. Understanding the timing and mechanisms of this closure is essential for reconstructing regional paleogeography, oceanic circulation, and the broader implications for global climate during the Neogene. The upper part of the mixed carbonate-siliciclastic Qom Formation in Central Iran provides a valuable archive of depositional and tectonic changes associated with this transition. An integrated multiproxy approach was applied to reconstruct depositional environments, sequence stratigraphy, and relative sea-level variations. This approach allows for the identification of major facies associations and the influence of both global and local factors on sedimentation patterns. The results indicate that deposition occurred on a carbonate ramp, influenced by both eustatic sea-level fluctuations and synsedimentary tectonic activity. Spatial variations in terrigenous input, interpreted from facies and provenance data, indicate that synsedimentary active basement faulting segmented the basin into shallow platform and deeper ramp environments. These tectonic controls, in combination with sea-level changes strongly influenced by eustacy, governed the overall stratigraphic architecture and paleogeographic evolution of the Qom Basin. This study provides new insights into the mechanisms that controlled the final stages of Tethyan Seaway closure, highlighting the complex interplay between regional tectonism and global climatic events in shaping Early Miocene marine basin. These findings contribute to a broader understanding of how tectonic and eustatic processes jointly influence basin evolution in marginal marine settings.