<p>This study investigates the vein- and skarn-type Pb–Zn–Fe mineralization in Tsauni, southern Gwagwalada Area Council, Abuja, north-central Nigeria, using geochemical, mineral chemistry and sulfur isotope (δ³⁴S) data to constrain the source of ore-forming fluids and the petrogenesis of the host metagranitoids. The metagranitoid suite comprises migmatite, granite gneiss, augen, biotite, and hornblende gneisses/amphibolite with subordinate metagabbro, diorite, granite, pegmatite intrusions and ultramafic relicts. Two mineralization styles are recognized: (1) vein-type orebodies hosted by augen and migmatized hornblende/amphibolite gneisses in the southwest, and (2) skarn-type mineralization developed along shear and contact zones between granite–pegmatite intrusions and calc-silicate leucogneiss–amphibolite assemblages in the northeast. Geochemical analyses for major and trace (including rare earth) elements using inductively coupled plasma emission spectrometry and mass spectrometry respectively revealed that the metagranitoids are mafic to felsic in composition (SiO₂ is between 50.53 and 75.80&#xa0;wt.%), Pb–Zn values reach &gt;10,000 and 200&#xa0;ppm in some of the metagranitoids and skarn while the samples with high Fe₂O₃ content correspond with the magnetite- enriched samples as revealed in the BSE images from microprobe analysis. These rocks are calc-alkaline and moderately to strongly peraluminous as shown in the K₂O–SiO₂ and A/NK vs. A/CNK diagrams indicating derivation from partial melting of a basaltic protolith with crustal assimilation. Microprobe analysis of biotite indicates ore-forming conditions of high temperature, low acidity and elevated oxygen fugacity. Mineral chemistry indicate that major ore minerals include galena, magnetite, pyrite, subordinate sphalerite and chalcopyrite. δ³⁴S values for galena and pyrite range from −3.4 to 0.2‰ in the skarn and −3.7 to 0.1‰ in the metagranitoids, while a mineralized quartz vein yields −4.4‰, suggesting minor involvement of meteoric or seawater-derived fluids. Overall, the results suggest that the mineralizing fluids were primarily magmatic–metamorphic in origin, later modified by lower-temperature hydrothermal or meteoric interactions during the late stages of mineralization.</p><p><b>Highlights</b></p><p>1. Vein- metagranitoids and skarn-type Pb–Zn–Fe mineralization identified in Tsauni, Abuja.</p><p>2. Host metagranitoids are calc-alkaline and peraluminous in composition.</p><p>3. δ³⁴S values indicate mixed magmatic and meteoric fluid contributions.</p><p>4. Ore fluids formed under high-T, low-acidity, and high oxygen fugacity.</p><p>5. Late hydrothermal overprint modified the primary magmatic signatures.</p>