1977 Volume 27 Issue 145 Pages 323-330
Minor elements in the ore minerals from the Mamut porphyry copper deposit, East Malaysia, have been analyzed by ion microprobe. Analyzed ore minerals are chalcopyrite, pyrite and pyrrhotite. These mineralsoccur in quartz veinlets in the biotite zone, tremolite-actinolite zone, hornblende zone of adamellite porphyry, and serpentinite. Besides major elements, Ti, Cr, Mn, Co, Ni, Cu and Zn were detected as minor elements in most samples, and Zr or Pb was also detected in a few samples.
The present result shows several valuable suggestions to the genesis of this deposit. (i) High concentration of Ni in chalcopyrite from serpentinite suggests that the source of nickel was the serpentinite, while the uniformity of zinc content in chalcopyrite regardless of the kind of country rock suggests that zinc in ore-forming fluids was not derived from the country rocks.(ii) The fact that the sulfides from the hornblende zone of adamellite porphyry where gaseous inclusions are dominant are generally poor in minor elements, indicates that minor elements were more concentrated in highly saline solutions than in sulfide minerals. (iii) The fluid inclusion data (NAGANO et al., 1977) and the distribution of minor elements between chalcopyrite and pyrite indicate that no remarkable temperature gradient existed in mineralization of the core and ore-shell. A wide range of the distribution coefficients, therefore, suggests that some pairs of chalcopyrite-pyrite were not formed in equilibrium.
