Investigation of platinum-group minerals (PGM) from Pindos chromitites (Greece) using hydroseparation concentrates

Grammatikopoulos, Tassos; Kapsiotis, Argyrios; Zaccarini, F.; Tsikouras, Basilios; Hatzipanagiotou, Konstantin; Garuti, Giorgio

doi:10.1016/j.mineng.2007.04.010

Cited by 13 publications

(21 citation statements)

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“…Any further increase of f(S 2 ) or decrease of T (or both) will promote the precipitation of Os-rich sulfide (namely erlichmanite) because Os partitions preferentially into the sulfide phase with falling temperature. Grammatikopoulos et al (2007) showed that the primary PGM assemblage of the chromitites from the Milia area is dominated by laurite and not by IPGE alloys and sulfarsenides (e.g., Prichard et al 2008), followed by Os-Ir-Ru alloys. The present analytical data suggest that Ru-rich alloys precipitated during an initial stage of crystallization characterized by high T and low f(S 2 ), followed by Ru-rich laurite with increasing f(S 2 ).…”

Section: Origin Of the Primary Pgm Assemblagementioning

confidence: 98%

“…The first description of PGM from the Milia chromitites was made by Grammatikopoulos et al (2007) in the context of a comparative study between the PGM assemblages of high-Cr chromitites from different areas of the Pindos massif. The authors recovered the PGM in concentrates and showed that the PGM assemblage inTrodUcTion The role of chromian spinel as an important collector of platinum-group elements (PGE) has been confirmed in investigations of the PGE content of different types of chromitites worldwide (e.g., Augé 1985, Ferrario & Garuti 1990, Pedersen et al 1993, Garuti et al 1999, Ahmed & Arai 2003.…”

Section: Previous Work On the Pgm Of Milia Chromititesmentioning

confidence: 99%

“…5C). The textural features of the grains recovered have been described by Grammatikopoulos et al (2007), where PGM are classified as primary or secondary on the basis of their internal morphology and qualitative compositional data.…”

Section: A Comparison Of Pgm Discovered In Situ With Those Identifiedmentioning

confidence: 99%

“…ophiolite complex has been investigated during the last two decades by Economou-Eliopoulos & Vacondios (1995), Tarkian et al (1996), Economou-Eliopoulos et al (1999), Grammatikopoulos et al (2007), and Prichard et al (2008). Their results indicate that two distinctive compositional groups of chromitites can be documented, solely on the basis of chromian spinel, high-Cr and high-Al types, each of which shows a relatively restricted compositional variation.…”

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confidence: 99%

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Chromian Spinel Composition and Platinum-Group Element Mineralogy of Chromitites From the Milia Area, Pindos Ophiolite Complex, Greece

Kapsiotis

Grammatikopoulos

Tsikouras

et al. 2009

The Canadian Mineralogist

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The chromitites of the Milia area in the Pindos ophiolite complex, in Greece, were investigated for their platinum-group mineral (PGM) content. The chromitites are massive, more rarely disseminated in texture and occur as small pods. They are composed of magnesiochromite crystals with Cr# [Cr/(Cr + Al)] between 0.80 and 0.84, and Mg# [Mg/(Mg + Fe 2+ )] between 0.54 and 0.72. The total platinum-group-element (PGE) contents in chromitites are relatively low (≤170 ppb), although they may locally be higher (up to 1059 ppb). The IPGE (Os, Ir and Ru) predominate over the PPGE (Rh, Pt and Pd). The PGM assemblage, consistent with the geochemical data, is dominated by laurite and Os-Ir-Ru alloys that occur both as single and composite grains, generally less than 15 mm in size. Laurite has a wide range of Os-for-Ru substitution [Ru/(Ru + Os): 0.42-0.99], whereas primary alloys are enriched in Ru (up to 73.80 wt.%). Some laurite crystals exhibit an anomalous pattern of zoning. Such zoning requires an inversion of the normal T-f(S 2 ) trend in magmatic systems, and is herein considered to be due to postmagmatic processes. Some Ru-rich alloy grains contain relatively high Rh and Pt abundances, similar to those of residual sulfides in mantle peridotites. This feature suggests that these alloys may represent residual PGM phases from earlier episodes of melt extraction from the severely depleted mantle unit of the Pindos ophiolite complex. Combined compositional data indicate that the Milia chromitites formed from a hydrous boninitic melt in a suprasubduction-zone environment.Keywords: chromitites, platinum-group minerals (PGM), laurite, alloys, ophiolites, Pindos, Greece. Certains grains d'alliages riches en Ru contiennent des teneurs relativement élevées en Rh et Pt, tout comme les sulfures résiduels de péridotites du manteau. Ces grains d'alliage pourraient donc représenter des MGP résiduels après l'extraction antérieure de liquide silicaté, laissant un manteau très stérile dans le complexe ophiolitique de Pinde. Les données combinées sur la composition indiquent que les chromitites de Milia se sont formées à partir d'une magma hydraté boninitique dans un milieu au dessus de la zone de subduction.(Traduit par la Rédaction)

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Section: Origin Of the Primary Pgm Assemblagementioning

confidence: 98%

Section: Previous Work On the Pgm Of Milia Chromititesmentioning

confidence: 99%

Section: A Comparison Of Pgm Discovered In Situ With Those Identifiedmentioning

confidence: 99%

mentioning

confidence: 99%

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Chromian Spinel Composition and Platinum-Group Element Mineralogy of Chromitites From the Milia Area, Pindos Ophiolite Complex, Greece

Kapsiotis

Grammatikopoulos

Tsikouras

et al. 2009

The Canadian Mineralogist

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“…Therefore, caution is needed when these results are used for petrological interpretations. The investigation of concentrates has been used as a supplementary method to in situ investigation, to further understand the formation of PGM and the evolution of the Earth's mantle [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Platinum-Group Minerals (PGM) from Othrys Chromitites (Greece) Using Superpanning Concentrates

et al. 2016

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Platinum-group minerals were concentrated using superpanning from two composite chromitite samples, which were collected from two old mines within the Othrys ophiolite. This method allows for the recovery of a broad spectrum of these rare and fine-grained minerals, and helps to better identify them and interpret their origin. Major differences between the east and west Othrys ophiolites were determined, probably as a result of their different origin and evolution. Primary Os-, Ir-, and Ru-bearing platinum-group minerals (IPGM)-alloys and the Rh-, Pt-and Pd-bearing platinum-group minerals (PPGM) occur only in the east Othrys chromitite, indicating an evolution from initially low f S2 conditions at shallower mantle levels with the subsequent implication of a S-saturated ascending fluid. In contrast, the absence of primary IPGM-alloys in west Othrys chromitite indicates that S saturation had been attained. The presence of erlichmanite suggests that sulphur fugacity eventually increased significantly in both suites. Substantial fluctuations of a fluid phase, likely related to serpentinising fluids, modified the platinum-group minerals (PGM) assemblage of west Othrys, and resulted in a large diversity of secondary PGM minerals. The limited number of secondary species developed in the east Othrys indicate that secondary processes were also different in the two suites.

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Mineralogy, composition and PGM of chromitites from Pefki, Pindos ophiolite complex (NW Greece): evidence for progressively elevated fAs conditions in the upper mantle sequence

et al. 2010

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Investigation of platinum-group minerals (PGM) from Pindos chromitites (Greece) using hydroseparation concentrates

Cited by 13 publications

References 10 publications

Chromian Spinel Composition and Platinum-Group Element Mineralogy of Chromitites From the Milia Area, Pindos Ophiolite Complex, Greece

Chromian Spinel Composition and Platinum-Group Element Mineralogy of Chromitites From the Milia Area, Pindos Ophiolite Complex, Greece

Investigation of Platinum-Group Minerals (PGM) from Othrys Chromitites (Greece) Using Superpanning Concentrates

Mineralogy, composition and PGM of chromitites from Pefki, Pindos ophiolite complex (NW Greece): evidence for progressively elevated fAs conditions in the upper mantle sequence

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