Mineralogical and geochemical characterisation of granite columns from the ancient city of Tyana (Niğde, Türkiye) and implications for their origin

In this article, the mineralogical, petrographic and geochemical properties of the granite columns, which are significant architectural elements in the ancient city of Tyana in the Cappadocia region, are documented and their origins are inferred. Tyana granite columns have porphyro-aphanitic texture and are characterized by mega crystals. The main mineral assemblage in the the granite columns consists of K-feldspar, quartz, plagioclase, biotite, amphibole and accessoy titanite, zircon and opaque minerals. XRD analysis supports the primary mineral assemblage. CRS (Confocal Raman Spectroskopy) studies also revealed that the plagioclase is andesine and amphibolite is actinolite in composition. In addition, geochemical analyses revealed that the granite columns are calc-alkali and granodiorite in composition. In the tectonic evaluation, the granite samples are located in the area of volcanic arc granitoids. According to all analysis results, the Tyana granite columns are compatible with the Horoz granitoids. All the above features will be an important step for the conservation and restoration of future ancient structures.