History/Deposit types
Types of mineral deposits
Where ore comes from: 30 deposit types, how each one forms, what it holds and the famous mines dug into it.
Banded iron formation (Superior and Algoma types)Iron oreThin layers of iron-rich rock alternating with chert, in beds of great lateral extent.Carbonatite and alkaline intrusionRare earths, Niobium, Phosphate rock, Iron oreRound igneous complexes with a core of carbonate rock that hold rare earths, niobium, phosphate and iron.Epithermal vein (Creede type)Gold, Lead, Zinc, CopperQuartz-carbonate veins with galena, sphalerite, chalcopyrite, tellurides and gold in volcanic rocks.Evaporite potashPotashPotassium salt beds in thick evaporite basins.Heavy mineral sands (shoreline placer)Titanium minerals, Zirconium (zircon), Rare earthsNarrow bodies of sand rich in ilmenite, rutile and zircon along old beaches and dunes.Ion-adsorption clay rare earthsRare earthsWeathered clay from which rare earths are leached, mined in southern China and valued for medium and heavy rare earths.Kimberlite and lamproite pipeDiamondsCarrot-shaped pipes of volcanic breccia that carry diamonds up from the mantle.Laterite-type bauxiteAluminium, GalliumAluminium-rich weathering crust, mainly gibbsite and boehmite.Layered intrusion PGM and chromite (Bushveld type)Platinum, Chromium, Nickel, CopperPlatinum-group metals in sulphide layers and chromitite layers in big layered mafic and ultramafic intrusions.Lithium brine (salar)LithiumSalty groundwater in a closed desert basin that is rich in dissolved lithium and is pumped to the surface and evaporated.Lithium-caesium-tantalum (LCT) pegmatiteLithium, Caesium, Tantalum, BerylliumVery coarse-grained granite bodies, small but rich in rare minerals, that carry lithium, caesium and tantalum.Magmatic nickel-copper-PGE sulphideNickel, Copper, PlatinumSulphide melt that separated from mafic or ultramafic magma and settled as lenses and layers.Marine phosphoritePhosphate rockBeds of phosphate pellets and nodules within marine sediments.Metamorphic graphite (flake, amorphous and vein)Graphite (natural)Graphite in carbonaceous metamorphic rock, as flake, amorphous graphite or high-purity veins.Mississippi Valley-type (MVT) lead-zincZinc, LeadSphalerite and galena in limestone and dolostone, with no link to igneous rock.Nickel lateriteNickel, CobaltNickel-rich soil layers made by deep tropical weathering of ultramafic rock.Olympic Dam type (iron oxide copper-gold-uranium)Copper, Uranium, Gold, SilverA huge hematite-rich breccia body with copper, uranium, gold and rare-earth minerals.Orogenic gold (low-sulphide gold-quartz veins)GoldGold in large, long quartz veins cutting metamorphosed volcanic and sedimentary rocks.Placer gold and tinGold, Tin, PlatinumGold, platinum-group alloys or cassiterite concentrated in river gravels and beaches.Podiform chromiteChromiumPods of chromite in deformed ultramafic rock of ophiolites.Porphyry copperCopper, Molybdenum, Gold, SilverCopper sulphide in many fine veinlets and scattered grains through a large body of altered porphyry rock and the rock around it.Quartz-pebble conglomerate gold-uranium (Witwatersrand type)Gold, UraniumGold, uranium and some platinum-group metals in ancient river-laid conglomerate beds.Sandstone-hosted (roll-front) uraniumUraniumUranium oxides in permeable sandstone, in tabular bodies or crescent-shaped rolls.Sediment-hosted stratabound copperCopper, SilverCopper sulphides scattered through grey or black beds that sit within red-bed sandstone and shale sequences.Sedimentary exhalative (SEDEX) zinc-leadZinc, LeadSheet-like beds of zinc and lead sulphide laid down with black shale in basins.Sedimentary manganeseManganeseBeds of manganese carbonate and oxide laid down in shallow sea around the rim of oxygen-poor basins.Tin greisen and tin veinTin, Tungsten, BerylliumTin oxide in altered granite near its roof, in veins, stockworks and pipes.Tungsten skarnTungsten, MolybdenumScheelite in lime-silicate rock formed where a granite meets limestone.Unconformity-related uraniumUranium, GoldUranium as pitchblende in breccias and fractures close to an ancient erosion surface under younger sandstone.Volcanogenic massive sulphide (Kuroko type)Copper, Zinc, LeadLenses of massive iron, copper and zinc sulphide laid down on the sea floor in volcanic rocks.
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