The
worldwide association of low-sulfidation epithermal gold mineralisation, bimodal
rhyolitic-basaltic volcanism and rifting is confirmed in New Zealand. In
the currently productive Coromandel epithermal-gold province reported Ar-Ar
dating of adularia from low sulfidation deposits falls into two groups at 6 and
7 Ma. Bimodal rhyolitic-basaltic volcanism has been reported to be K-Ar dated at
9 to 7 Ma and 6 to 5.5 Ma. Epithermal gold mineralisation in Northland is
spatially associated with bimodal basaltic-rhyolitic volcanism, with rifting
cogenetic with that in the CVZ. The Taupo Volcanic zone (TVZ) is sufficiently
young that the presence of a segmented rift with recent bimodal
rhyolitic-basaltic volcanism can be genetically associated with epithermal gold
mineralisation, which occurs as both fossil occurrences and in active geothermal
fields. This reinforces the known potential prospectiveness of the Coromandel
area and increases that of Northland and the Taupo Volcanic
Zone.