Magmatic sulphides: why Cu, Ni & PGE get in!

There seems to be a lot of interest in magmatic sulphide deposits from readers, or should I rather say an interest to better understand these interesting deposits. My last post focused on the central role of sulphur in these magmatic systems, how the sulphide portion of the magma separates from the silicate portion and then how the sulphide melt deposits itself within the magma chamber. We also spoke about how Fe gets into the sulphide melt. But what about the important stuff, the nickel, copper and PGE?

ARM's nickel sulphide Nkomati mine in South Africa. It's Cu/Ni ratio ma suggest Bushveld lineage...

ARM’s nickel sulphide Nkomati mine in South Africa. It’s Cu/Ni ratio ma suggest Bushveld lineage…

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Magmatic sulphide deposits: “Only for the masters!”

A colleague and I visited a university geology department in the vicinity of a project we were working to do a presentation on the geology of the project. We had been invited by a professor who’s research interests were amongst other things, mafic-ultramafic rocks and he had invited us as our project was hosted by such. He relayed an interesting story to us that day: Final-year students in the department were required to complete a research project and a student had approached the professor and told him that he is interested in doing a project about ultramafic rocks. The professor immediately retorted: “No! Ultramafic are only for the masters!” The professor was of course not talking about Masters’ degree students but referring to the dedication and possible the intelligence required to understand these rock types and their associated deposits.

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