Diachronous initiation of Arabia–Eurasia collision from eastern Anatolia to the southeastern Zagros Mountains since middle Eocene time

The persistent debate over the timing of initial Arabia–Eurasia collision has eluded consensus for decades, with most estimates ranging widely from ~50 to 10 Ma along both Anatolian and Zagros segments orogen. Here, we independently evaluate location using a quantitative plate tectonic reconstruction that is first include entire Arabian microcontinent regions north in eastern Anatolia, northwestern Iran, Caucasus. combines new kinematic constraints recent global models synthesis available on crustal shortening continental back-arc subduction restore pre-collisional geometries Eurasian margins track their interaction through time. Our preferred model suggests underthrusting, or soft collision, relatively thin passive margin Eurasia occurred by ca. 42 Bitlis suture zone began transmitting strain across central Caucasus, Iran. Collision inception then propagated westward into Anatolia southeastward Mountains late Eocene time (ca. 40–35 Ma), latest early Oligocene time, 35–25 finally southeastern middle Miocene 25–15 Ma). diachroneity Arabia led widespread upper-plate (Eurasian) contraction similarly time-transgressive magmatic lull lagged behind onset ~2–12 Myr. By incorporating north, this highlights diachronous nature during became progressively younger southeast strike zone.