Paleomagnetism From Central Iran Reveals Arabia-Eurasia Collision Onset at the Eocene/Oligocene Boundary

We present two robust and well-dated paleomagnetic poles from upper Eocene and Oligocene volcanics in the Urumieh-Dokhtar magmatic arc, Central Iran. These two poles place Iran & SIM;3.7 & DEG;-3 & DEG; of latitude south of its present position between ca. 40 and 23 Ma. Our new paleomagnetic declination data indicate that the Central Iran block may have experienced a & SIM;11.6 & DEG; clockwise rotation since the Late Eocene. We integrated our new data with the retrodeformed margins of the Zagros collision zone and contemporaneous Arabia positions to better constrain the age and configuration of the Arabia and Eurasia assembly process. In our model, the Arabia-Eurasia collision occurred first in the western Main Zagros suture between ca. 35 and 30 Ma and then diachronously spread eastwards. Our paleogeographic reconstruction and initial continental collision timing supports the Arabia-Eurasia collision as a first-order driver of global cooling, Red Sea rifting, and Mediterranean extension.