METALE SZLACHETNE W ZŁOŻU MORRISON, SUDBURY, KANADA

Abstrakt

PRECIOUS METALS IN THE MORRISON DEPOSIT, SUDBURY, CANADAAbstract. The Morrison deposit, located in Sudbury Mining Camp, produces ore containing copper, nickel, platinum, palladium and gold. Chalcopyrite dominates the mineral assemblage, while the main Ni-bearing phases are pentlandite and millerite. Cubanite, mackinawite, pyrrhotite, magnetite, sphalerite and galena are present too. Bornite is the main mineral in the peripheral parts of veins, often containing native silver veinlets. Platinum occurs as discrete PGM minerals: composite grains of moncheite (PtTe2) with hessite (Ag2Te); maslovite (PtBiTe) and sperrylite (PtAs2) are rare. Palladium can occur as a substitution in pentlandite and as discrete PGM minerals: michenerite (PdBiTe) and paolovite (Pd2Sn). Tellurides and bismuth-tellurides often display Pt-Pd and Bi-Te substitutions. Gold is present as a native element and as electrum. A zonation in the occurrence of elements can be explained by fractional crystallization of magmatic sulphides. There is a possibility of partial remobilization of precious metals (especially gold and palladium) by later hydrothermal and/or metamorphicprocesses with associated authigenic quartz, silicates (epidote, amphiboles) and secondary magnetite containing sulphide inclusions.