Examples of Ore Deposits

• Magmatic Cu-Ni-PGE-Cr• Hydrothermal --- veins --- metasomatic skarns *** magmatic , meteoric, or sea water origin• Low-Temperature --- Banded Iron Formations --- Residual weathering/ supergene enrichment

Ore-localizing embayment in footwall gabbro, Zone 3

Peridotite

Gabbro

Komatiitic basalt

Slate

Nickel plate Electrowinning cathode

Uses of platinum

Pt wire Pt mesh

Mechanisms of Mineral Precipitation

• Temperature decline• Pressure change• Dilution• Change in oxidation state (e.g. Eh)• Change in pH• Change in parameters like cation

concentration or volatile pressure

ZnCl2 + H2S = ZnS(s) + 2H+ + 2Cl-

CuCl+ + FeCl2 + 2H2S =

CuFeS2(s) + 4H+ + 3Cl-

PbCl+ + H2O + ½ S2 = PbS(s) + 2H+ +

Cl- + ½ O2

Example Reactions