Magmatic platinum nanoparticles in metasomatic silicate glasses and sulfides from Patagonian mantle xenoliths
Por:
Maria Gonzalez-Jimenez, Jose, Roque-Rosell, Josep, Jimenez-Franco, Abigail, Tassara, Santiago, Nieto, Fernando, Gervilla, Fernando, Baurier, Sandra, Proenza, Joaquin A., Saunders, Edward, Deditius, Artur P., Schilling, Manuel, Corgne, Alexandre
Publicada:
1 may 2019
Resumen:
Platinum-rich nanonuggets (s.l., nanoparticles) are commonly produced in
experiments attempting to quantify the solubility or partitioning of
noble metals in silicate and sulfide melts. However, it has been thought
that these represent artifacts produced during quenching of the
experimental runs. Here, we document nanoparticles (similar to 20-80nm)
of Pt-rich alloys and arsenides dispersed in high-temperature
metasomatic silicate glasses and in base-metal sulfides (BMS) entrained
in them, found interstitially between minerals of mantle peridotite
xenoliths from southern Patagonia. Pt-rich nanoparticles found in the
interstitial silicate glasses are frequently attached to, or in the
proximities of, oxides (ilmenite or Cr-spinel) suggesting a close link
between the formation of the oxides and the Pt-rich nanoparticles. The
interstitial glasses in the studied xenoliths correspond to quenched
alkaline basaltic melts that infiltrated the subcontinental lithospheric
mantle (SCLM) at>1000 degrees C at an oxygen fugacity (fO(2)) near the
fayalite-magnetite-quartz (FMQ) buffer. Experimental works indicate that
at these conditions the crystallization of oxides such as ilmenite or
Cr-spinel may lower fO(2) to promote the precipitation of Pt-rich
nanoparticles. The investigation of four Pt-rich nanoparticles hosted in
two different pentlandite grains using a combination of focused ion beam
and high-resolution transmission electron microscopy (FIB/HRTEM) show
that these nanoparticles consists of polycrystalline aggregates<10nm
that are randomly oriented relative to their sulfide host matrices.
These observations suggest that these nanoparticles could be segregated
either directly from the infiltrating alkaline basaltic melt prior to
sulfur saturation in the silicate melt, or from droplets of immiscible
sulfide melt once sulfur saturation was achieved. The formation of
Pt-rich nanoparticles in high-temperature melts, either silicate or
sulfide, provides new clues on the processes of fractionation, transport
and concentration of Pt in the mantle.
Filiaciones:
Maria Gonzalez-Jimenez, Jose:
Univ Granada, Fac Ciencias, Dept Mineral & Petrol, Avda Fuentenueva S-N, Granada 18002, Spain
Roque-Rosell, Josep:
Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, Fac Ciencies Terra, E-08028 Barcelona, Spain
Univ Barcelona, IN2UB Fac Quim, Inst Nanociencia & Nanotecnol, Ave Diagonal 645, E-08028 Barcelona, Spain
Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona, Barcelona, 08028, Spain
Institut de Nanociència i Nanotecnologia, IN2UB Facultat de Química, Universitat de Barcelona, Av. Diagonal 645, Barcelona, 08028, Spain
Jimenez-Franco, Abigail:
Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, Fac Ciencies Terra, E-08028 Barcelona, Spain
Univ Barcelona, IN2UB Fac Quim, Inst Nanociencia & Nanotecnol, Ave Diagonal 645, E-08028 Barcelona, Spain
Univ Nacl Autonoma Mexico, Posgrad Ciencias Tierra, Ciudad Univ, Mexico City 04510, DF, Mexico
Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona, Barcelona, 08028, Spain
Institut de Nanociència i Nanotecnologia, IN2UB Facultat de Química, Universitat de Barcelona, Av. Diagonal 645, Barcelona, 08028, Spain
Posgrado en Ciencias de la Tierra, Universidad Nacional Autónoma de México, Ciudad Universitaria, Delegación Coyoacán, Mexico City, 04510, Mexico
Tassara, Santiago:
Univ Chile, Dept Geol, Santiago 8370450, Chile
Univ Chile, CEGA, Santiago 8370450, Chile
Department of Geology and Andean Geothermal Center of Excellence (CEGA), Universidad de Chile, Santiago, 8370450, Chile
Nieto, Fernando:
Univ Granada, Fac Ciencias, Dept Mineral & Petrol, Avda Fuentenueva S-N, Granada 18002, Spain
Univ Granada, CSIC, IACT, Granada 18100, Spain
Departamento de Mineralogía y Petrología, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, Granada, 18002, Spain
Instituto Andaluz de Ciencias de la Tierra (IACT), Universidad de Granada-CSIC, Granada, 18100, Spain
Gervilla, Fernando:
Univ Granada, Fac Ciencias, Dept Mineral & Petrol, Avda Fuentenueva S-N, Granada 18002, Spain
Univ Granada, CSIC, IACT, Granada 18100, Spain
Departamento de Mineralogía y Petrología, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, Granada, 18002, Spain
Instituto Andaluz de Ciencias de la Tierra (IACT), Universidad de Granada-CSIC, Granada, 18100, Spain
Baurier, Sandra:
Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, Fac Ciencies Terra, E-08028 Barcelona, Spain
Univ Barcelona, IN2UB Fac Quim, Inst Nanociencia & Nanotecnol, Ave Diagonal 645, E-08028 Barcelona, Spain
Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona, Barcelona, 08028, Spain
Institut de Nanociència i Nanotecnologia, IN2UB Facultat de Química, Universitat de Barcelona, Av. Diagonal 645, Barcelona, 08028, Spain
Proenza, Joaquin A.:
Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, Fac Ciencies Terra, E-08028 Barcelona, Spain
Univ Barcelona, IN2UB Fac Quim, Inst Nanociencia & Nanotecnol, Ave Diagonal 645, E-08028 Barcelona, Spain
Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona, Barcelona, 08028, Spain
Institut de Nanociència i Nanotecnologia, IN2UB Facultat de Química, Universitat de Barcelona, Av. Diagonal 645, Barcelona, 08028, Spain
Saunders, Edward:
Univ New England, Div Earth Sci, Sch Environm & Rural Sci, Armidale, NSW 2351, Australia
Division of Earth Sciences, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia
Deditius, Artur P.:
Murdoch Univ, Sch Engn & Informat Technol, Murdoch, WA 6150, Australia
School of Engineering and Information Technology, Murdoch University, Murdoch, WA 6150, Australia
Schilling, Manuel:
Univ Austral Chile, Inst Ciencias Tierra, Valdivia 5090000, Chile
Instituto de Ciencias de la Tierra, Universidad Austral de Chile, Valdivia, 5090000, Chile
Corgne, Alexandre:
Univ Austral Chile, Inst Ciencias Tierra, Valdivia 5090000, Chile
Instituto de Ciencias de la Tierra, Universidad Austral de Chile, Valdivia, 5090000, Chile
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