Geochemical and Mineralogical Differentiation of Tepekent Basalts: a Multivariate Analysis Approach (NW of Konya-Central Anatolia)

Abstract

This study investigates the mineralogical, petrographic, and geochemical characteristics of Miocene-aged basaltic rocks from the Tepekent region to distinguish and correlate them with other members of the Sulutus Volcanic Complex (SVC), particularly the Ulumuhsine and Yükselen basalts. Advanced geostatistical methods such as Principal Component Analysis (PCA), Uniform Manifold Approximation and Projection (UMAP), and k-medoids clustering analysis were applied to correlate the basaltic lava flows. While some overlaps were identified in whole-rock compositions, significant differences were observed in the mineral chemistry. The investigated basalts are primarily composed of plagioclase, with lesser amounts of olivine, pyroxene, and Fe-Ti oxides. Clinopyroxenes from the Tepekent basalts exhibit oscillatory zoning in MgO, CaO, Cr2O3, and TiO2 contents, indicating magma recharge from a more mafic mantle source. Olivine phenocrysts show disequilibrium with their host magma but are in equilibrium with the most mafic Ulumuhsine basalt, suggesting they were derived from earlier solidified phases and subsequently incorporated into the system during magma ascent or convective processes within the magma chamber. Irregular An fluctuations and sieve textures in plagioclase crystals further support the presence of magma replenishment processes. Although isotopic data are indispensable in provenance studies to definitively identify magma sources and establish genetic relationships in greater detail, this study demonstrates how mineral chemistry and geostatistical analyses can effectively differentiate basaltic lava flows and elucidate complex magma chamber processes. The findings highlight the interplay between crustal contamination, mantle-derived magma replenishment, and multi-stage magmatic evolution, providing valuable insights into the volcanic history of Central Anatolia.