Au crystal growth on natural occurring Au—Ag aggregate elucidated by means of precession electron diffraction (PED)

Roqué-Rosell, Josep; Serra, Joaquim Portillo; Aiglsperger, Thomas; Plana-Ruiz, Sergi; Trifonov, T.; Proenza, Joaquín A.

doi:10.1016/j.jcrysgro.2017.11.031

Cited by 8 publications

(3 citation statements)

References 24 publications

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“…The TEM is equipped with the commercial PED system DigiSTAR manufactured by NanoMEGAS ® . The PED patterns were recorded with a Stingray external camera by Gatan ® (Pleasanton, CA, USA) and the X-ray maps and spectra with an X-ray microanalysis INCA ® ultrathin window Si (Li) detector by Oxford Instruments ® (Abington, Oxfordshire, UK) while operating the TEM at 200 kV with a beam size used in this mode of~15 nm as in [37].…”

Section: Nanoscale Study Of the Zoned Laurite Crystalmentioning

confidence: 99%

“…Once the automated acquisition of several thousand PED patterns was completed, phase identification was performed for each individual pattern, by comparing with previously generated model templates using the Topspin ® software package (Version 3.1, Nanomegas, Brussels, Belgium). The subsequent data processing of the PED patterns followed the procedure of [37,38].…”

Section: Nanoscale Study Of the Zoned Laurite Crystalmentioning

confidence: 99%

“…Additionally, bright field maps were obtained under precessed illumination in parallel to correlation index map images to stress features such as compositional variations, in-grain precipitates and allow highlighting of selective crystalline domains [37]. By combining all these data, we aimed to obtain the mineral phase distribution of chromite, laurite and erlichmanite at sub-micron scale within the PGM aggregate.…”

Section: Nanoscale Study Of the Zoned Laurite Crystalmentioning

confidence: 99%

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Nanoscale Structure of Zoned Laurites from the Ojén Ultramafic Massif, Southern Spain

et al. 2019

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We report the first results of a combined focused ion beam and high-resolution transmission electron microscopy (FIB/HRTEM) investigation of zoned laurite (RuS2)-erlichmanite (OS2) in mantle-hosted chromitites. These platinum-group minerals form isolated inclusions (<50 µm across) within larger crystals of unaltered chromite form the Ojén ultramafic massif (southern Spain). High-magnification electron microscopy (HMEM), high angle-annular dark field (HAADF) and precession electron diffraction (PED) data revealed that microscale normal zoning in laurite consisting of Os-poor core and Os-rich rims observed by conventional micro-analytical techniques like field emission scanning electron microscope and electron microprobe analysis (FE-SEM and EPMA) exist at the nanoscale approach in single laurite crystals. At the nanoscale, Os poor cores consist of relatively homogenous pure laurite (RuS2) lacking defects in the crystal lattice, whereas the Os-richer rim consists of homogenous laurite matrix hosting fringes (10–20 nm thickness) of almost pure erlichmanite (OsS2). Core-to-rim microscale zoning in laurite reflects a nonequilibrium during laurite crystal growth, which hampered the intra-crystalline diffusion of Os. The origin of zoning in laurite is related to the formation of the chromitites in the Earth’s upper mantle but fast cooling of the chromite-laurite magmatic system associated to fast exhumation of the rocks would prevent the effective dissolution of Os in the laurite even at high temperatures (~1200 °C), allowing the formation/preservation of nanoscale domains of erlichmanite in laurite. Our observation highlights for the first time the importance of nanoscale studies for a better understanding of the genesis of platinum-group minerals in magmatic ore-forming systems.

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Section: Nanoscale Study Of the Zoned Laurite Crystalmentioning

confidence: 99%

Section: Nanoscale Study Of the Zoned Laurite Crystalmentioning

confidence: 99%

Section: Nanoscale Study Of the Zoned Laurite Crystalmentioning

confidence: 99%

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