Distribution and occurrence of some naturally-occurring polytypes of molybdenite in Australia and Papua New Guinea
Titel:
Distribution and occurrence of some naturally-occurring polytypes of molybdenite in Australia and Papua New Guinea
Auteur:
Ayres, D.
Verschenen in:
Australian journal of earth sciences
Paginering:
Jaargang 21 (1974) nr. 3 pagina's 273-278
Jaar:
1974
Inhoud:
156 samples of naturally-occurring molybdenite from 87 localities in Australia have been examined to determine the distribution of the hexagonal (2H1) and rhombohedral (3R) polytypes. 90% of the specimens examined are 2H1 polytypes, the remainder being 3R and mixtures of 2H1 and 3R polytypes. The 3R and mixed polytypes are more abundant in porphyry copper deposits or as disseminations, in veins, and in garnet-quartz pipes in granite. 2H1 polytypes are the sole modification observed in pegmatites, quart-pegmatite pipes, simple quartz veins, and skarns. The highest average concentrations of rhenium are in molybdenite from porphyry copper deposits, quartz porphyry pipes, skarn deposits, garnet-quartz pipes, and pegmatites. Low concentrations occur in molybdenite which is disseminated or in quartz veins in granite and in quartz or pegmatitic pipes. Molybdenites in which the 2H1 polytype is dominant have a lower average rhenium content than those with dominant 3R polytype.
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