Geochemical and Mineralogical Analyses of Karst-Type Bauxites from the Akseki-Kuyucak Region (Antalya, Turkey): A Comprehensive Statistical Method Utilizing REEs and Major Element Data

Abstract

The Akseki-Kuyucak bauxite deposits, located in the Western Taurus Belt in southwestern T & uuml;rkiye, represent karst-type bauxite mineralization derived from carbonate platform phases. This work integrates field observations, X-ray diffraction (XRD) analysis, and extensive geochemical data, including major, trace, and rare earth elements (REEs), to clarify the mineralogical characteristics, geochemical processes, and genetic implications of the deposits. Field and petrographic investigations indicate that the bauxite deposits occur as irregular fills and lens-shaped formations on paleokarstic surfaces of carbonate substrates. The XRD examination reveals that the major minerals in the bauxite samples are boehmite, hematite, and anatase, with some samples exhibiting a predominance of calcite, indicating a strong genetic relationship between the ore bodies and the carbonate host rocks. Major oxide analysis reveals a distinct compositional disparity between bauxitic and carbonate-dominated materials: bauxitic samples exhibit elevated Al2O3 and Fe2O3 levels, with reduced SiO2 and CaO concentrations. In contrast, carbonate-rich samples show higher CaO and loss-on-ignition values. Ternary discrimination diagrams categorize most bauxitic samples into the ferritic bauxite and robust lateritization domains, indicating substantial weathering and residual enrichment processes. The trace element and REE studies reveal Sigma LREE values ranging from 22.3 to 240.2 ppm, with a right-skewed distribution indicating heterogeneous enrichment. Correlation studies indicate that Sigma LREE has a positive correlation with SiO2 and K2O, suggesting that the enrichment of REEs is more closely associated with silicate/clay minerals than with iron oxide phases. Furthermore, spider diagrams and the study of immobile components emphasize the significance of residual concentration processes in bauxitization. In contrast, modest TiO2 levels indicate a composite source derived from both insoluble carbonate remnants and detrital siliciclastic materials. In summary, the Akseki-Kuyucak deposits are categorized as intricate karst bauxite systems, characterized by significant lateritization, regulated accumulation governed by paleokarst characteristics, and a complex geochemical evolution. The results demonstrate that integrating mineralogical, geochemical, and statistical methods provides a thorough framework for evaluating REE behaviors and the effects of source-related factors in karst bauxite deposits.