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Noble metals potential of sulfide-saturated melts from the subcontinental lithosphere
Citation
Kamenetsky, VS and Maas, R and Fonseca, ROC and Ballhaus, C and Heuser, A and Brauns, M and Norman, MD and Woodhead, JD and Rodemann, T and Kuzmin, DV and Bonatti, E, Noble metals potential of sulfide-saturated melts from the subcontinental lithosphere, Geology, 41, (5) pp. 575-578. ISSN 0091-7613 (2013) [Refereed Article]
Copyright Statement
Copyright 2013 Geological Society of America.
DOI: doi:10.1130/G34066.1
Abstract
The origin of vast accumulations of nickel and platinum in some continental magmatic rocks is still enigmatic, but ultimately linked to silicate-sulfide liquid immiscibility. The exact composition of pristine sulfide melts has proved extremely difficult to document and understand, largely because of the ephemeral, reactive qualities and small quantities of such melts. Here we report the discovery of Fe-Ni sulfide melt globules highly enriched in noble metals (Pt, Pd, Au; 120 ppm total platinum group elements [PGE]) within an unusual high-Mg andesitic glass (8.2 wt% MgO, 57.3 wt% SiO2) dredged from the southern Mid-Atlantic Ridge, near the Bouvet triple junction. The composition of this glass indicates derivation of its parental silicate melt from a garnet pyroxenite mantle source with pronounced "continental" isotopic (Pb, Sr, Nd, Hf, Os, O) signatures. We infer that the chemical properties of this high-temperature (1250 °C) melt, notably high SiO2 and Ni (310 ppm) contents, promoted sulfide saturation at low pressures in a purely oceanic setting, and propose that this unique example, with its likely origin in the continental lithospheric mantle, may be a useful analogue for incipient Ni-PGE-sulfide melt generation and magmatic PGE enrichment. © 2013 Geological Society of America.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | Garnet pyroxenite, high temperature, liquid immiscibility, lithospheric mantle, Mid Atlantic Ridge, platinum group elements, silicate melts, triple junction |
| Research Division: | Earth Sciences |
| Research Group: | Geology |
| Research Field: | Igneous and Metamorphic Petrology |
| Objective Division: | Mineral Resources (excl. Energy Resources) |
| Objective Group: | Mineral Exploration |
| Objective Field: | Precious (Noble) Metal Ore Exploration |
| UTAS Author: | Kamenetsky, VS (Professor Vadim Kamenetsky) |
| UTAS Author: | Rodemann, T (Dr Thomas Rodemann) |
| ID Code: | 84570 |
| Year Published: | 2013 |
| Funding Support: | Australian Research Council (DP1092823) |
| Web of Science® Times Cited: | 16 |
| Deposited By: | Centre for Ore Deposit Research - CODES CoE |
| Deposited On: | 2013-05-21 |
| Last Modified: | 2014-04-10 |
| Downloads: | 0 |
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