TY - JOUR
T1 - PGE distribution in base-metal alloys and sulfides of the New Caledonia ophiolite
AU - Mcmahon, Greg
AU - Auge, T
AU - Cabri, L J
AU - Legendre, O
AU - McMahon, G
AU - Cocherie, A
N1 - Times Cited: 8 5
PY - 1999
Y1 - 1999
N2 - An Upper Eocene ophiolite nappe covering some 40% of New Caledonia consists of depleted mantle harzburgites, locally covered by mafic and ultramafic cumulates. These mantle harzburgites in places show an enrichment in sulfide and alloy (heazlewoodite, pentlandite, awaruite, millerite and native copper), accompanied by anomalous concentrations of the PGE, as revealed by the whole-rock analyses of three sulfide-enriched samples and by the heavy-mineral concentrates obtained from these samples (up to 1835 ppb Ir, 1527 ppb Ph, 9718 ppb Pt, 11,494 ppb Pd and 988 ppb Au). Although studies to determine the PGE-carrier minerals by SEM were unsuccessful, SIMS depth profiles show that Pt is strongly enriched in awaruite, albeit varying widely among grains, e.g., from 4 to 1210 ppm for 21 grains in one sample. In contrast, 11 grains of pentlandite from the same sample do not exceed 10 ppm Pt, whereas 10 out of 12 grains of heazlewoodite show no detectable Pt, and the Pt content of the other two grains is estimated to be very low (
AB - An Upper Eocene ophiolite nappe covering some 40% of New Caledonia consists of depleted mantle harzburgites, locally covered by mafic and ultramafic cumulates. These mantle harzburgites in places show an enrichment in sulfide and alloy (heazlewoodite, pentlandite, awaruite, millerite and native copper), accompanied by anomalous concentrations of the PGE, as revealed by the whole-rock analyses of three sulfide-enriched samples and by the heavy-mineral concentrates obtained from these samples (up to 1835 ppb Ir, 1527 ppb Ph, 9718 ppb Pt, 11,494 ppb Pd and 988 ppb Au). Although studies to determine the PGE-carrier minerals by SEM were unsuccessful, SIMS depth profiles show that Pt is strongly enriched in awaruite, albeit varying widely among grains, e.g., from 4 to 1210 ppm for 21 grains in one sample. In contrast, 11 grains of pentlandite from the same sample do not exceed 10 ppm Pt, whereas 10 out of 12 grains of heazlewoodite show no detectable Pt, and the Pt content of the other two grains is estimated to be very low (
M3 - Article
SN - 0008-4476
VL - 37
SP - 1147
EP - 1161
JO - Canadian Mineralogist
JF - Canadian Mineralogist
ER -