Investigation of sillimanite using Raman spectroscopy and evidence of metamorphism under low-pressure and high-temperature conditions in metapelitic rocks of the contact metamorphic aureole of Mishow, northwest Iran.

Document Type : Original Article

Authors

1 Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran

2 Department of Geology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran

10.22128/ijcm.2025.3058.1012

Abstract

The Ediacaran granitoid complex of Mishow, located in the southwest of Marand County, northwestern Iran, covers an area of approximately 50 km² and appears as a semi-deep, horseshoe-shaped intrusion. Petrographically, the complex comprises a compositional range from leucogranite to diorite. The granites include two distinct types: ,Microstructural and petrographic analyses reveal fibrolitic sillimanite with bent textures, concentrated in high-strain zones, which indicate progressive deformation in high-grade metapelites. These observations are well supported by Raman spectroscopy data, where peak shifts in sillimanite spectra reflect structural and crystallographic changes induced by pressure and deformation.Therefore, Raman spectroscopy serves as a sensitive and precise tool for qualitatively and quantitatively constraining metamorphic conditions such as pressure, temperature, and strain intensity. The strong agreement between petrographic and spectroscopic data enhances the reliability of the interpretations.

Keywords: Contact metamorphism, Sillimanite, Microstructure, Raman spectroscopy

Keywords


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