Mica Types as Indication of Magma Nature, Central Anatolia, Turkey

This study focuses on the nature of giant micas occurring at the contact between the ozvatan (foid-bearing) syenites and the metamorphic basement in Central Anatolia. The studied micas are dark greenish-black in color and crystallized within vein shape like bodies as a narrow lens. The origin and processes responsible for the formation of these independent crystals of the giant micas were investigated by mineralogical, petrographical and geochemical analyses with the use of Confocal Raman Spectroscopy (CRS), Fourier Transform Infrared (FTIR) Spectroscopy, X-Ray Diffraction (XRD), Polarized Energy Dispersive X-Ray Fluorescence Spectrometer (PED-XRF) and Electron Probe Micro Analysis (EPMA). According to XRD, CRS, FTIR and EPMA data, the giant micas are phlogopite. EPMA results reveal that studied mica minerals represent the products of re-equilibrated primary mica characterized by high MgO and FeO and low Al2O3 and TiO2 contents. The trace element concentrations of the giant micas display similar patterns with the upper crust. The giant micas are crystallized within small cubicles from an alkaline magma and their composition is possibly modified by a mixing event between the crust- and mantle-derived magmas and contaminated at varying extent by the basement metamorphic rocks.

Automated summary

This study investigates the nature of giant micas found at the contact between foid-bearing syenites and the metamorphic basement in Central Anatolia. The micas are dark greenish-black in color and form narrow lens-shaped bodies. Through mineralogical, petrographical, and geochemical analyses, it was determined that the micas are phlogopite and have been modified by a mixing event between crust- and mantle-derived magmas, as well as contaminated by the metamorphic rocks of the basement.