Volume 14, Number 3 (1987)

Ore Deposit Models #12. The Platinum Group Element Deposits: Classification and Genesis

A. James Macdonald
Ontario Geological Survey, Toronto, Ontario
Published September 9, 1987
How to Cite
Macdonald, A. J. (1987). Ore Deposit Models #12. The Platinum Group Element Deposits: Classification and Genesis. Geoscience Canada, 14(3). Retrieved from https://journals.lib.unb.ca/index.php/GC/article/view/3501


The platinum group element deposits are subdivided within a genetic framework; the three principal deposit types are formed by (1) Orthomagmatic, (2) Alluvial or (3) Hydrothermal processes. The Orthomagmatic class can be further subdivided into three sub-classes: deposits that formed as a result of (a) magma mixing, (b) contamination of magma by material from an external source, and (c) deuteric fluid activity, i.e. flow of fluids derived from the same magma as the intrusive host rocks. Alluvial deposits include modem placers, which commonly show an association with mafic/ultramaflc complexes such as "Alaskan-" or "Alpine-type" intrusions, and paleoplacers, of which the Witwatersrand is the only known example that is sufficiently rich in the platinum group of elements to permit recovery. Hydrothermal platinum-palladium deposits include those in which a hydrothermal system has been channelled through mafic/ultra-maflc host rocks from which the precious metals may have been leached. Examples include the New Rambler Mine in Wyoming, the Rathbun Lake occurrence in Ontario, and the Nicholson No. 2 uranium ores in the Beaverlodge area of Saskatchewan. The alkaline suite of porphyry copper deposits comprises the second type of hydrothermal mineralization in which platinum and palladium are significantly concentrated. The huge Kupferschiefer Cu-Ag deposits in Central Europe contain locally significant concentrations of platinum and palladium, associated with redox fronts in carbonaceous shales. At the Coronation Hill deposit, in Australia's Northern Territory, PGE are also spatially associated with carbonaceous material, and with uranium and gold mineralization.