Near-surface hydrothermal activity in the eastern otago schist

Abstract

The quartz-gold-stibnite-bearing Consolidated Lode at Nenthorn, eastern Otago, contains abundant prismatic quartz crystals and hydrothermal breccia. Fluid inclusion data imply that boiling occurred during mineral deposition at about 190°C at very shallow levels, possibly within 120 m of the surface. This type of vein system may be common in eastern Otago. Gold may be found beneath Sb and/or Hg deposits formed by similar near-surface hydrothermal activity. © Crown copyright 1987.