Mesothermal gold deposits of southern Alaska and Westland, New Zealand have both formed at the seaward edge of major
collisional zones in the Pacific basin. In Alaska, production of large fluid volumes correlates in time with the addition of heat
into the lower parts of the accreted terranes in the late stages of collisional orogeny. This heat was critical for driving both the
metamorphic reactions that released the large volumes of fluid that carried the gold, and the contemporaneous widespread
anatexis and magmatism. In Alaska's Chugach terrane, this heat was produced by subduction of a spreading ridge beneath the
North America continental margin in the Eocene. The resulting products were the S-type granites and gold-bearing veins. The
similar widespread S-type plutonism and gold veining in Westland's Buller terrane suggest that a similar tectonic event could
have triggered ore formation along the southeastern edge of Gondwanaland. Based on the Alaskan model, a Devonian or Early
Carboniferous age is favoured for high volume metamorphogenic fluid generation and gold vein formation in Westland.