Geologists uncover evidence of a missing Late Cretaceous magmatic arc in northwestern Iran
Mountains preserve evidence of ancient oceans, moving continents and tectonic processes that have shaped Earth over millions of years. Later deformation, erosion and burial, however, can obscure important parts of this geological record. An international research team led by Istanbul Technical University (ITU) has identified evidence of a previously unrecognized Late Cretaceous continental…
Geologists have uncovered evidence of a missing magmatic arc from the Late Cretaceous period in northwestern Iran, according to a new study published in Geoscience Frontiers. Led by Istanbul Technical University, an international research team collaborated with researchers from various institutions to investigate the region's geological history.
The study reveals that the Azerbaijan Continental Magmatic Arc, active around 101-97 million years ago, played a significant role in the tectonic evolution of the region, which is now part of the Arabia–Eurasia collision zone. The geological record of the arc was obscured by tectonic deformation, erosion, basin burial, and younger Eocene magmatism.
The researchers analyzed volcanic and plutonic rocks from several locations in northwestern Iran, using zircon U-Pb geochronology, Hf isotope analyses, and whole-rock geochemistry. These methods allowed them to constrain the ages and sources of the rocks, revealing characteristics consistent with subduction-related continental arc magmatism.
The discovery of this previously unrecognized magmatic arc extends the conventional understanding of Iran's magmatic history, which has primarily focused on the Sanandaj–Sirjan and Urumieh–Dokhtar Magmatic Arcs. The study also highlights the importance of the Siah Cheshmeh–Khoy–Misho–Tabriz Fault as a tectonic boundary associated with the reorganization of the Neo-Tethyan system.
By recognizing ancient magmatic arcs that have been fragmented or obscured by later geological processes, researchers can gain new insights into the subduction, arc migration, continental growth, and closure of ancient oceans during the Late Cretaceous.
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