In
New
Zealand, volcanogenic massive sulfide (VMS)
deposits are found in three main geological environments associated with:
1. ophiolitic basalts of Oligocene age
in Northland and East Cape (eg Pupuke, Pakotai,
Parakao and Lottin Point);
2. with chert and pillow lava in
greywacke sequences of Permian-Jurassic age (Torlesse and Waipapa terranes; eg
Kawau
Island, Te Kumi and
Maharahara) and their metamorphic equivalents (Haast Schist; eg Moke Creek and
Waitahuna); and
3.
with greenschists (metabasalts) and
metaserpentinite of Permian-Triassic age (Ponamu Ultramafics) in Westland (eg Bowen and
Wilberg ranges).
The
deposits consist of small lenses of disseminated to massive sulfide minerals,
mainly pyrite and chalcopyrite. Small quantities of copper ore were mined from
some deposits in the 1800s (eg Kawau Island from 1846), with the last mining at
Parakao from 1961 to 1966. Several deposits have been recently examined for
their gold potential with assays on sulfide rock samples as high as 75 g/t Au
(Lottin Point).