An international research team led by Istanbul Technical University has discovered evidence of a previously unrecognized continental magmatic arc in northwestern Iran that formed during the Late Cretaceous period. Named the Azerbaijan Continental Magmatic Arc, the volcanic system was active from approximately 101 to 97 million years ago, when the ancient Neo-Tethys Ocean was undergoing significant geological changes. The discovery adds a missing chapter to understanding the region’s complex magmatic history.
Researchers identified the ancient volcanic system by examining volcanic and plutonic rock samples collected across northwestern Iran, with particular focus on formations along the Siah Cheshmeh-Khoy-Misho-Tabriz Fault. The team employed advanced analytical techniques including zircon U-Pb geochronology to determine rock ages, Hf isotope analyses to trace material origins, and whole-rock geochemistry to evaluate chemical composition. These methods revealed geological signatures consistent with continental arc magmatism, a process triggered when one tectonic plate descends beneath another and generates magma that rises through overlying continental crust.
The newly identified volcanic arc represents a previously overlooked episode of continental arc activity separate from two major known geological features in Iran: the Sananda-Sirjan Magmatic Arc and the Urumieh-Dokhtar Magmatic Arc. The discovery suggests that multiple tectonic processes shaped northwestern Iran during the Late Cretaceous. Researchers believe the Siah Cheshmeh-Khoy-Misho-Tabriz Fault may mark a significant tectonic boundary connected to changes in the ancient Neo-Tethys Ocean system, potentially including slab rollback and volcanic arc migration.
The research, published in Geoscience Frontiers, demonstrates how geological records can become obscured over millions of years through tectonic deformation, erosion, sedimentary burial, and subsequent volcanic activity. The international collaboration included scientists from institutions in Turkey, China, Switzerland, and Iran. By reconstructing fragments of this ancient volcanic system, researchers have refined understanding of how continental crust developed and how vast ancient oceans eventually closed, contributing to broader knowledge of Eastern Mediterranean, Middle Eastern, and Western Asian geological evolution.
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