Mafic-ultramafic magmatism of the Noril'sk region and a problem of sources of ore matter

摘要

The metallogenic character of the Norilsk region (Siberia) is determined by a regular zonal distribution of mafic-ultramafic intrusions which comprise three contrasting groups distinguished by specific compositional and structural features (Distler et al., 1988)1 Mesocratic completely-differentiated ore-bearing intrusions (Norilsk I, Talnakh, Kharaelakh, Chernogorsky and Mikchandinsky massifs) are characterised by(1) Well-developed petrochemical, geochemical and mineralogical differentiation of sulphide-silicate matter over a vertical sequence, since gabbroic rocks occur in the upper and lower parts of the bodies and olivine has settled to form horizon of ultramafic rocks within the layered series. There is a continuous upward increase in SiO2, CaO, Al2O3, TiO2, Na2O and K2O contents of whole rocks and a decrease in MgO and Cr2O3 contents starting from the picritic layer.