Goroa Creek

Goroa Creek cumulate layered Pt-Pd prospect. The Goroa Creek Pt-Pd propsect is located 175 km NNE from Port Moresby, at the NW end of the Papuan Ultramafic Belt.  Irregularly spaced creek-side outcrop grab sampling from across the stirke of the Goroa Creek mafic-ultramafic sequence has identified three cumulate-layered PGM reefs, the first occurrence of such mineralisation in the SW Pacific (Fig 2).  All three reefs occur in a layered gabbro sequence.  Pt:Pd ratios of >1 are typical of cumulate-layered PGM mineralization.

The lowermost 'Reef' 1 is located near the base of a plagioclase- and sulphide-rich gabbro, immediately above its contact with utramfics.  A single sample from the reef assayed 244 ppb Pt+Pd. A second thicker 'Reef' 2 occurs in the upper part of the plagioclase- and sulphide-rich gabbro unit and straddles the contact with overlying weakly layered plagioclase-poor gabbro.  This reef is about 100m thick and averages 60 ppb Pt+Pd.  Highest assay is 114 ppb Pt+Pd.  A third narrower 'Reef' 3 is present in the upper part of the weakly layered plagioclase-poor gabbro unit.  Highest assay is 96 ppb Pt-Pd and the average is 54 ppb Pt+Pd.
 

Fig 2 - Goroa Creek Pt-Pd prospect geology