Geochemistry and Petrogenesis of Neogene Perlitic–Spherulitic Rocks from the Galumak Area, Urumieh–Dokhtar Magmatic Assemblage: Evidence for Syn- to Post- Collisional Magmatism in Southeastern Iran

Zarei, Serveh; Dargahi, Sara; Arvin, Mohsen; Shaker, Alireza

doi:10.22071/gsj.2026.572727.2243

Geochemistry and Petrogenesis of Neogene Perlitic–Spherulitic Rocks from the Galumak Area, Urumieh–Dokhtar Magmatic Assemblage: Evidence for Syn- to Post- Collisional Magmatism in Southeastern Iran

Articles in Press

Document Type : Original Research Paper

Authors

Serveh Zarei

Sara Dargahi

Mohsen Arvin

Alireza Shaker

Department of Geology, College of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran

10.22071/gsj.2026.572727.2243

Abstract

The Neogene perlitic rocks of the Galumak area, located northeast of Bardsir and within the Urumieh-Dokhtar magmatic assemblage, are associated with limited extent rhyolitic lava flows. These perlites appear to have formed through hydration of rhyolites, progressively devitrifying into spherulites. Geochemical data reveal a rhyolitic composition, high-K calc-alkaline affinity, and meta- to peraluminous character. Spider diagrams and rare earth element (REE) patterns exhibit LREE enrichment relative to HREE, with negative Nb-Ti and Eu anomalies, indicative of an arc-related source, involvement of continental crust, and the role of fractional crystallization (particularly plagioclase and zircon) in magma evolution. Tectonomagmatic discrimination diagrams place the samples in a syn- to post-collisional setting. Geochemical evidence, including incompatible element ratios, suggests that the magma originated from partial melting of meta-greywacke in the middle to upper continental crust. Considering the tectonic setting and Miocene age, the formation of these acidic rocks is attributed to melting of thickened continental crust in a syn- to post-collisional environment, likely triggered by processes such as slab breakoff or lithospheric delamination. These findings provide significant insights into the closure of the Neotethys Ocean and the crustal evolution of Iran during the Miocene.

Keywords

Perlite

Spherulite

Syn- to post-collisional magmatism

Metagraywacke partial melting

Miocene

Kerman, Urumieh-Dokhtar magmatic assemblage

Subjects