| Инд. авторы: | Kamenetsky V.S., Maas R., Fonseca R.O.C., Ballhaus C., Heuser A., Brauns M., Norman M.D., Woodhead J.D., Rodemann T., Kuzmin D.V., Bonatti E. |
| Заглавие: | Noble metals potential of sulfide-saturated melts from the subcontinental lithosphere |
| Библ. ссылка: | Kamenetsky V.S., Maas R., Fonseca R.O.C., Ballhaus C., Heuser A., Brauns M., Norman M.D., Woodhead J.D., Rodemann T., Kuzmin D.V., Bonatti E. Noble metals potential of sulfide-saturated melts from the subcontinental lithosphere // Geology. - 2013. - Vol.41. - Iss. 5. - P.575-578. - ISSN 0091-7613. - EISSN 1943-2682. |
| Внешние системы: | DOI: 10.1130/G34066.1; SCOPUS: 2-s2.0-84876791373; WoS: 000317911700016; |
| Реферат: | eng: 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.
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| Ключевые слова: | Atlantic Ocean; triple junction; sulfide; silicate melt; saturation; pyroxenite; platinum group element; platinum; nickel; isotopic composition; immiscibility; high temperature; gold; garnet; continental lithosphere; chemical property; andesite; Mid-Atlantic Ridge; Silicates; Precious metals; Platinum; Nickel deposits; Nickel; Magnesium; Lead; Glass; Chemical properties; Triple junction; Silicate melts; Platinum group elements; Mid Atlantic Ridge; Lithospheric mantle; Liquid immiscibility; High temperature; Garnet pyroxenite; Sulfur compounds; |
| Издано: | 2013 |
| Физ. характеристика: | с.575-578 |