Otago Schist and
Klondike Schist are two Paleozoic-Mesozoic metamorphic belts on the
circum-Pacific margin in which there has been a long history of abundant
alluvial gold mining, but only minor hard-rock gold mining.

Modern exploration for
hard-rock gold is ongoing in both belts, and the active Macraes mine in Otago
(>2 Moz production) highlights the hard-rock potential of the geological
setting of these belts. Hard-rock gold mineralisation in both belts formed in
the latter stages of schist exhumation, after rocks were subjected to major
regional ductile folding and then uplifted through the brittle-ductile
transition. The majority of known hard-rock gold-bearing systems in both belts
consist of well-defined, but generally discontinuous, vein swarms. Most Otago
veins are hosted in steeply dipping post-metamorphic normal faults and
fractures. However, the Macraes mine is hosted by a late-metamorphic shear zone,
and much ore is sulphide-impregnated auriferous schist. Goldbearing veins in the
Klondike schist are hosted primarily in
extensional sites associated with post-metamorphic compressional structures.
Some disseminated sulphide mineralisation is associated with Klondike veins and this is important as it extends the
exploration target for these veins. No foliation-parallel late metamorphic
mineralisation has been identified in the Klondike but exposure is relatively poor compared with
Otago and both schist belts are highly prospective for deposits of this
type.