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Gold production in New Zealand has been significant since the mid 1800s, totalling 900,000 kg (29 M oz) to 2005. In addition, there is potential for an additional 1.23 t (41 M oz) of gold in known and undiscovered deposits. Most gold in New Zealand has originated from mesothermal or epithermal hydrothermal systems. Mesothermal gold occurs in low-medium metamorphic grade sedimentary and schist host rocks, typically within quartz veins or shear zones that were formed during deformation. These deposits are largely confined to Otago, West Coast and Marlborough. Epithermal gold occurs in volcanic terrains associated with near-surface active hydrothermal systems, either in quartz veins or disseminated through strongly altered zones. Major epithermal deposits have been found in Coromandel, and significant prospects are known in Northland and the Taupo Volcanic Zone. Major alluvial gold mining has occurred downstream of mesothermal gold deposits in Otago and the West Coast of the South Island.
Considerable data are available in digital formats to assist exploration for new gold deposits using Geographic Information Systems (GIS) software. These data include modern geological mapping, geochemistry, geophysics, mineral occurrences, topographic data and cultural data, as well as derivative themes such as geophysical interpretation, metamorphic grade, and structural trends. Geological mapping data include rock type, age, and stratigraphic association, as well as alteration zones, faults, folds, dikes, veins, and structural measurement data. The spatial relationships between these data and known gold deposits have been statistically quantified using the Weights of Evidence technique within GIS software. Stronger correlating data have been combined to create map models that quantify prospectivity. Many poorly explored areas of elevated prospectivity have been identified and reinforce the notion that New Zealand has considerable potential for future gold discoveries.