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Examples of Ore Forming Processes. Igneous: Intrusive. A. Separation of mineral by density Example chromite the ore mineral for Cr B. Separation of immiscible liquid Example: Ni and Cu C. Late Stage Crystallization Example: Cu and Au Hydrothermal Fluids Example: Au.
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Igneous: Intrusive • A. Separation of mineral by density • Example chromite the ore mineral for Cr • B. Separation of immiscible liquid • Example: Ni and Cu • C. Late Stage Crystallization • Example: Cu and Au • Hydrothermal Fluids • Example: Au
Igneous: Volcanic • A. Fumaroles • Example: S, Au • B. Mid-ocean ridges • Example: Cu, Pb, Zn, Au • C. Hydrothermal Fluids • Example: Au, Ag
Sedimentary Processes • A. Density Differences • Example: Au, Ti, Diamonds • B. Weathering • Example: Bauxite and other laterites • C. Chemical Precipitation • Example: Banded Iron Formations, Salt, Gypsum
Placer Deposits as an example • Resistate Minerals • Tough • Heavy • Chemically resistant
Pt, Cassiterite (for Sn), Chromite (Cr), Columbite (for Nb), Cu, Diamond, Garnet • Ilmenite (for Ti), Magnetite and Hematite (for Fe), Monazite (for rare earth elements) • Ruby and Sapphire • Rutile (for Ti), zircon (for Zr), and xenotime (for Y)
Placer Deposits • Eluvial • Stream or alluvial placers • Beach placers