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Platinum Group Elements :car: - Coggle Diagram
Platinum Group Elements
:car:
Economical mineral deposits in the Earths crust are rare
Largest and significant deposits
Commonly platinum and palladium
Associated with sulfide minerals
Layered mafic/ultramafic igneous intrusions
Cumulate deposit
Magmatic sulfide deposits
Form during fractional crystallisation
Mafic magma becomes saturated in sulfide
When magma can no longer hold sulfur in solution
It exsolves
Producing immiscible sulfide liquid
Droplets are denser than magma
Sinks tthrough
Siderophiles
Iron loving
Along with gold, nickle
If they dont interact with iron
They act like Chalcophiles
Ore loving
Silver, copper
Concentrate in molten sulfide
Bond more readily with sulfur than oxygen
Prefer metallic bonds
Concentrate in molten iron
Gathered by sinking sulfide droplets
Removed from magma
Form layers
few mm to m
Theories for sulfide saturation
Assimilation of country rock
Rich in sulfur
Most reasonable mechanism for large deposits
Silica contamination
Assimilation of silica rich country rock
Decrease the solubility of sulfur in mafic magma
Skaergaard Intrusion
Greenland
Most studied in the world
Magmatic sulfide layers rich in PGE
Gold, Selenium
Intruded during tertiary
North Atlantic was opening