Vanadium Enrichments of Meta-Gabbroic Rocks in central part of the Menderes Massif (Türkiye): The Incremental Effect of Magmatism and Metamorphism in Highly Siderophile Environments

Especially in the context of renewable energy, vanadium (V) is an important component of energy storage technology. Gabbroic rocks in crustal environments may host a considerable amount of V-bearing minerals such as magnetite, and ilmenite. This study focuses on primary V occurrences in Precambrian-Cambrian aged meta-gabbroic rocks of the Alaşehir-Manisa area in the central part of the Menderes Massif (Türkiye). The primary purpose of the study is twofold; 1) to determine the V potentiality of meta-gabbro and 2) to reveal the enrichment mechanism by determining the mineralogical and geochemical properties of gabbroic formations. The meta-gabbroic rocks in the study area can be divided into three subgroups based on the size distribution (fine, medium, and coarse) of the minerals. The ore-bearing minerals observed in the meta-gabbroic rocks are construed by magnetite, ilmenite, titanomagnetite, rutile, pyrite, and hematite. The high-grade metamorphism of Menderes Massif progressively affected the gabbroic rocks resulting in the partial and complete transition of ilmenite minerals to rutile. However, the effect of metamorphism gradually decreases from outward to inward zones of the intrusion allowing an intact vanadiferous ilmenite-rich core in the entire gabbro body. 

The V enrichments are both hosted by oxide and sulphide-bearing phases. While the oxide phases are constituted by ilmenite and Ti-magnetite exsolutions, the sulphide minerals are pyrite and minor chalcopyrite. The V content of the studied meta-gabbro range from 281 to 628 ppm, with an average of 514 ppm. Contents of SiO₂, Al₂O₃, Fe₂O₃, MgO, TiO₂, and P₂O₅ are between 68.8-38.9%, 7.93-15.4%, 6.87-17.8%, 3.21-8.86%, 1.24-5.64%, 0.19-1.13%, respectively. V shows moderate to strong correlation with Ti, Zn, and Ga (R²= 0.51, 0.86, and 0.87, respectively) and there is a lack of correlation with Fe, Ni, and Cu indicating V³⁺ ion substituted Fe³⁺ in magnetite and Ti³⁺ in ilmenite. The other meta-gabbro intrusions of Menderes Massif generally lacked Ti-V enrichments, therefore Alaşehir meta-gabbro intrusion may gain economic importance in case of a tighter supply trend of these critical elements.

Keywords: Vanadiferous gabbro; Magnetite; Ilmenite; Menderes Massif; Alaşehir-Manisa (Türkiye)