sedimenthosted

Sediment-hosted deposits are mineral deposits hosted by sedimentary rocks or formed within sedimentary basins. They develop when metal-bearing hydrothermal fluids move through permeable sedimentary rocks and precipitate sulfide or oxide minerals within stratigraphic horizons, often at basin margins, along faults, or at unconformities. The category includes several discrete deposit types that are sedimentary-rock hosted, with SEDEX (sediment-hosted exhalative) deposits being a prominent example formed by metal-rich fluids exhaling onto the sea floor and depositing laminated sulfide beds. Other forms are carbonate-hosted Mississippi Valley-type (MVT) zinc-lead deposits and sandstone-hosted uranium deposits, among others.

Key characteristics include widespread sulfide mineralization (notably Zn, Pb, Cu, Ag), laminated or bedded textures, and close association with reduced sedimentary rocks or evaporites. Mineralization is commonly stratiform or stratabound, and ore bodies often track sedimentary layers. Controls on mineralization include diagenetic processes, sediment porosity and permeability, and structural features such as faults and unconformities.

Economically, sediment-hosted deposits are important sources of zinc and lead, with copper, silver, and uranium exploited in various districts. They occur in continents across ancient and modern basins and are a major focus of exploration in sedimentary basins. Environmental considerations include management of sulfide-rich wastes and potential acid rock drainage.

See also SEDEX, MVT deposits, sedimentary ore deposits.