Abstract
Little information is known about the overlying topography, the structural setting, or the surface expression of the mineralizing systems of mesothermal Au deposits because they formed at several km depth and are only exposed after several km of erosion. This study attempts to define the nature of the upper portions of mesothermal deposits by examining evidence for hydrothermal activity in the Southern Alps of New Zealand. This region comprises a collisional mountain belt which has been active throughout the late Cainozoic and is still forming. Mesothermal Au deposits formed during the late Cainozoic deformation, and variable uplift has exposed auriferous veins at different crustal levels. Finally, comparisons are made with historically exploited Miocene mesothermal veins further south in the Otago schist.