Ancient Volcanic Arc Unearthed in Northwestern Iran
Researchers have identified remnants of a previously unknown continental magmatic arc in northwestern Iran that was active roughly 101 to 97 million years ago. The team named it the Azerbaijan Continental Magmatic Arc and connected it to the Late Cretaceous history of the Neo-Tethys Ocean. Geochemical and isotopic analyses of volcanic and plutonic rocks indicate the arc formed through subduction before later deformation and Eocene magmatism obscured it.
An international group coordinated at Istanbul Technical University gave the buried system the name Azerbaijan Continental Magmatic Arc. Its rocks date to roughly 101–97 million years ago, during the Late Cretaceous, when the Neo-Tethys Ocean was closing. The remnants now sit within the Arabia-Eurasia collision zone.
Volcanic and plutonic samples along the Siah Cheshmeh-Khoy-Misho-Tabriz Fault were analyzed using zircon uranium-lead dating, hafnium isotopes, and whole-rock chemistry. These methods indicated magma generation linked to a continental arc above a subducting plate. Later Eocene activity, erosion, and tectonic deformation had hidden much of the evidence.
This discovery could affect how geoscientists reconstruct the region’s tectonic past, potentially improving long-term geological understanding. Researchers and institutions across Iran, Türkiye, China, and Switzerland may deepen collaborations. For wider society, any benefits would likely be indirect, emerging through education, better maps, and informed planning rather than immediate applications.