TRACE-ELEMENT DISTRIBUTION IN THE SCHIST SURROUNDING A QUARTZ-SCHEELITE LODE, GLENORCHY, NEW-ZEALAND

Schist surrounding the scheelite-bearing Glenorchy Lode was analysed for Ni, Cu, Zn, As, Rb, Sr, Y, Zr, Nb, Sb, Cs, Ba, rare earth elements, W, Pb, Th, and U. The data were used to determine the presence and extent of a chemical halo, to elucidate the origin of the ore-forming elements, and to evaluate the potential of trace element analysis of host rocks in exploration for tungsten mineralisation in the Haast Schist. The trace element halos adjacent to the Glenorchy Lode are less than 1 m wide, and they appear to be closely related to a zone of intensely veined schist which represents a zone of high permeability in the wall rocks during mineralisation. Mass-balance calculations suggest that the tungsten was not derived by lateral secretion from the wall rock immediately adjacent to the mineralised lodes, but originated elsewhere in the Haast Schist, probably at deeper levels in the metamorphic pile. The chemical halos are too narrow to assist tungsten exploration, but study of the chemical variations may assist the establishment of a genetic model for the origin of the tungsten deposits, and in this way may be beneficial in the subsequent search for ore. © 1979 Taylor & Francis Group, LLC.