Petrochemical Investigation of Secondary Mineralized Volcanogenic Massive Sulfide (VMS) and Supergene Enrichment Economic Deposits in Jandrey-Annar, Upper Dir, Pakistan

This research was about the petrographic and geochemical study of the secondary mineralized Volcanic Massive Sulfide(VMS) deposits of Uthror Volcanics at the Jandrey-Annar study area. Sample examination underthe microscope indicates the presence of plagioclase feldspar, sericite, and secondary minerals, such as limonite, hematite, and malachite. Subhedral phenocrysts of pyrrhotite and a highly altered groundmass are indicative of post-magmatic hydrothermal alteration andfeldspar sericitization. (Quartz in veins andvugs with undulose extinctionindicatesrecrystallization.The secondary minerals formed by supergene processes were identified by the petrographicindex as the products of oxidation and weathering processes of primary sulfide ores. Loss on Ignition (LOI) returns vary from 3.24% to 4.72%, verifying the presence of hydrous mineral species and carbonates, typical for mature secondary mineralized VMSdeposits. The rocks are classified as tephrite-basanite, and trachybasalt based on geochemical analysis (AAS and XRF) with the following ranges in their concentrations:SiO₂(45–48%), Al₂O₃(16.02–18.63%), CuO (10.48–13.69%), and Fe₂O₃(5.49–6.20%). The SiO₂binary plots show positive trends for TiO₂, Al₂O₃, P₂O₅, and K₂O, and negative trends for Fe₂O₃, MgO, CaO, and Na₂O confirming fraction crystallization. High K₂O values indicatethe high-K calc-alkaline series. The 10Mn-TiO₂-10P₂O₅ternary plot classifies the rocks as oceanic island arc basalts, while the R1-R2 plotindicates a late orogenic environment. These results demonstrate mineralizationassociated with hydrothermal alteration and subduction-related magmatism. Based on analysisof variance (ANOVA) and t-test, high geochemical variation is represented by highly significant (p < 0.01) and significant (p < 0.05) enriched variables including CuO, Fe₂O₃, and MnO, with moderately varying SiO₂, TiO₂, Al₂O₃, and Na₂O, the results indicate hydrothermal alteration and episodic stages of secondary mineralization within the Uthror Volcanics. This high economic potential of the copper oredue to secondary mineralization and supergene enrichment processes has made the region an important target for mineral exploration.