Precious metals in magmas of East Greenland: Factors important to the mineralization in the Skaergaard intrusion

A survey of precious metals, Ni and Cu levels, and their mutual relationships in several magma suites of the East Greenland volcanic passive margin shows that the magma type which was parental to the Skaergaard intrusion was markedly enriched in Pt, Pd, and especially Au and relatively depleted in Cu compared to the preceding voluminous plateau basalt volcanism. It is likely that elevated levels of platinum-group minerals (PGM) and Au were critical to the generation of ore-grade precious metals in the intrusion. The discovery of a major PGM and Au deposit within the intrusion combined with these results suggests a set of criteria which might be critical to the formation of Skaergaard-type PGM deposits elsewhere in the province and worldwide. The Skaergaard mineralization appears to be a hitherto undescribed class of PGM and Au mineralizations.