Ore genesis accumulation of hematite gravels called "pisolites" which form channel-iron deposits. These are preferred because they are cheap to mine. Lead-zinc deposits are generally accompanied by silver, hosted within the lead sulfide mineral galena or within the zinc sulfide mineral sphalerite. Lead and zinc deposits are formed by discharge of deep sedimentary brine onto the sea floor (termed "sedimentary exhalative" or SEDEX), or by replacement of limestone, in skarn deposits, some associated with submarine volcanoes (called volcanogenic massive sulfide ore deposits or VMS), or in the aureole of subvolcanic intrusions of granite. The vast majority of SEDEX lead and zinc deposits
Mineral Exploration Research Centre deposits, volcanology, geochemistry, and alteration associated with hydrothermal copper-zine-(gold) volcanogenic massive sulfide ore deposits, structure, geochemistry, and alteration associated with hydrothermal orogenic lode gold deposits, mineralogy, geochemistry, and genesis of rare-element and rare-metal pegmatites, and the sedimentology of Mississippi Valley-type (MVT) Pb-Zn deposits and placer Au and U deposits. MERC and the Harquail School of Earth Sciences are a world-leaders in mineral deposits education, offering a Co-Op BSc in Mineral Exploration program, hosting the annual PDAC-sponsored Student-Industry Mineral Exploration Workshop, offering a fully modular ("block") Applied MSc degree in Mineral Exploration, and offering a PhD in Mineral Exploration and Precambrian