The Qandi Bolaq Cu–Pb–Zn deposit is located in the Central Iranian Zone, approximately 76 km southwest of Zanjan. Mineralization occurs within two distinct grey sandstone horizons in the third member of the Upper Red Formation. The first horizon (H-1) hosts Pb–Zn mineralization, with a thickness of about 1 meter and a length of approximately 100 meters. The second horizon (H-2) contains Cu mineralization, measuring 0.5 meters in thickness and about 50 meters in length. Mineralization is commonly associated with, and occurs around, plant fossil fragments, and is present in disseminated forms, solution seams, intergranular cement, and sulfide veinlets. Three alteration zones are recognized within the ore-bearing horizons: a red oxidized zone, a bleached zone, and a mineralized reduced zone. The main ore minerals are galena, sphalerite, pyrite, and chalcopyrite, while goethite, malachite, and azurite are products of supergene alteration. Ore textures include disseminated, framboidal, intergranular cement, lens-shaped, solution seam, vein-veinlet, and replacement textures. Geochemical analyses of mineralized samples, as well as barren red (oxidized zone) and grey (bleached zone) sandstone samples normalized to Upper Continental Crust and greywacke sandstone, show lower concentrations of trace elements and rare earth elements in mineralized samples compared to barren sandstones. Based on features such as tectonic setting, sedimentary environment, host rock, fossil content, geometry, ore textures, mineralogy, and alteration patterns, the Qandi Bolaq deposit is classified as a red bed-type, sediment-hosted Cu deposit. It is comparable to other Redbed-type Cu and Pb–Zn deposits in the Avaj–Zanjan–Tabriz–Khoy region.