The generation of precious metal sulphide deposits in the Skaergaard and related intrusions, East Greenland.

Precious-metal mineralisation occurs both within the Tertiary layered gabbroic intrusion and in some, but not all, of its surrounding gabbroic, 100-500 m wide metadykes. Within the Skaergaard intrusion, low-volume precious metal-bearing sulphide deposits with mostly magmatic S isotope ratios support theories that the PGE-Au Platinova reefs resulted from prolonged magma fractionation. Similar metal profiles suggest that a common magma also formed the spatially related macrodykes but significant crustal S isotope content in their precious metal mineralisation indicates localised crustal contamination, interaction with local basin sediments appearing to have determined their prospectivity.
Precious-metal mineralisation occurs both within the Tertiary layered gabbroic intrusion and in some, but not all, of its surrounding gabbroic, 100-500 m wide metadykes. Within the Skaergaard intrusion, low-volume precious metal-bearing sulphide deposits with mostly magmatic S isotope ratios support theories that the PGE-Au Platinova reefs resulted from prolonged magma fractionation. Similar metal profiles suggest that a common magma also formed the spatially related macrodykes but significant crustal S isotope content in their precious metal mineralisation indicates localised crustal contamination, interaction with local basin sediments appearing to have determined their prospectivity.