Ni-Cu sulfide deposits in mafic-ultramafic erogenic intrusions Examples from the Svecofennian areas, Finland

摘要

The Ni-Cu sulfide ores in synorogenic intrusions are considered unimportant because the type examples from Phanerozoic orogenic belts are of low-grade disseminated deposits. However, certain synorogenic deposits from Spain and Svecofennian belt of Fennoscandia include high-grade massive and breccia ores. The intrusions and related ores are contaminated and fractionated before final emplacement to the present position as separate magma pulses allowing sulfides to be injected separately either in the mafic-ultramafic intrusion or outside the intrusion as a high-grade off-set ore. Examples of Fennoscandian area will be given and a genetic model discussed.