Abstract
The highly siderophile element (HSE) contents of base-metal sulphides have been determined by laser-ablation microprobe (LAM)-ICPMS in abyssal peridotites from the Mid-Atlantic and South West Indian ridges. (Pd/Ir)(N) (0.007-505, N: CI-chondrite-normalised), (Pt/Ir)(N) (0.001-0.77) and (Rh/Ir)(N) (0.159-273) vary significantly between both grains and samples, irrespective of indicators of melt removal. but in line with bulk-rock platinum-group element (PGE) ratios and sulphide modal abundances. Positive deviations of PGE abundance ratios in whole-rock analyses are due to late-precipitated Cu-Ni-rich magmatic sulphides from incompletely extracted partial melts. These results contradict explanations of the HSE systematics of the oceanic mantle as reflecting global scale processes such as core-mantle exchange.
Original language | English |
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Pages (from-to) | 285-294 |
Number of pages | 10 |
Journal | Earth and Planetary Science Letters |
Volume | 189 |
Issue number | 3-4 |
Early online date | 27 Jun 2001 |
DOIs | |
Publication status | E-pub ahead of print - 27 Jun 2001 |