ORE-LECTURE 2
History of Earth
Ore deposits formed throughout history
Ore deposits related to Earth's changes
Ore deposits where life started
Uneven preservation
Veneer hypothesis: meteorite bombardment
to enrich in siderophile elements
Sudbury: impact related ore body.
Ni deposit, melt sulphate-silicate
Supercontinent cycle:
relation w/ ore deposits
Different styles of mineralisation
Different associations of metals
Cyclical distribution of deposits
Porphyry Cu-Au mineralisation associated w/ calc-alkaline volcanism and subduction zones
Evolving hydro/atmosphere
GOE: oxygen. Sulphur reacs differently, redox conditions in oceans changed, solubility of Fe changes
Microbial reduction
Modern deposit formation
Black smokers/hydrothermal vents-Cu + Zn
Fe-Mg crusts
Deep ocean
Good ore sources
Slow accretion, ocean chemistry/ecosystem impacts
Metallogenic provinces
Deposits associated
w/ metallogenic provinces
Region of crust where style
of mineralisation is predominant