Sulfide mineral chemistry and petrography and platinum group element composition in gabbroic rocks from the Southwest Indian Ridge

2002 ◽  
Author(s):  
D.J. Miller ◽  
P. Cervantes
Keyword(s):  
Platinum Group Element ◽  
Mineral Chemistry ◽  
Sulfide Mineral ◽  
Element Composition ◽  
Group Element ◽  
Southwest Indian Ridge ◽  
Indian Ridge ◽  
Platinum Group

Sulfide mineral chemistry and platinum-group minerals of the UG-2 chromitite in the northern limb of the Bushveld Igneous Complex, South Africa

2021 ◽  
Vol 59 (6) ◽  
pp. 1339-1362
Author(s):  
Malose M. Langa ◽  
Pedro J. Jugo ◽  
Matthew I. Leybourne ◽  
Danie F. Grobler
Keyword(s):  
Platinum Group Element ◽  
Mineral Chemistry ◽  
Sulfide Mineral ◽  
Sulfide Minerals ◽  
Group Element ◽  
Igneous Complex ◽  
Northern Limb ◽  
Platinum Group Minerals ◽  
Platinum Group ◽  
Bushveld Igneous Complex

ABSTRACT The UG-2 chromitite layer, with its elevated platinum-group element content, is a key marker horizon in the eastern and western limbs of the Bushveld Igneous Complex and the largest platinum-group element chromite-hosted resource of its kind in the world. In contrast, much less is known about its stratigraphic equivalent in the northern limb, the “UG-2 equivalent” (UG-2E) chromitite. Recent studies on chromite mineral chemistry show similarities between the UG-2 and sections of the UG-2E, but also that the UG-2E was partially contaminated by assimilation of local metasedimentary rocks. Here, we provide a detailed characterization of sulfide minerals and platinum-group minerals in a suite of samples from the UG-2E and compare the results with data obtained from a reference suite of samples from the UG-2. Results from petrographic observations, electron probe microanalysis, laser ablation-inductively coupled plasma-mass spectrometry, quantitative evaluation of materials by scanning electron microscopy, and δ34S isotopes show that: (1) sulfide minerals in the UG-2E and UG-2 consist mainly of pentlandite-chalcopyrite-pyrrhotite, but pyrrhotite is significantly more abundant in the UG-2E and almost absent in the UG-2; (2) iron contents in pentlandite from the UG-2E are significantly higher than in the UG-2; (3) platinum-group element contents within sulfide minerals are different between the two chromitites; (4) UG-2E platinum-group minerals are dominated by arsenides and bismuthotellurides, and by alloys and platinum-group element-sulfide minerals in the UG-2; (5) sulfide mineral chemistry and δ34S values indicate some crustal contamination of the UG-2E; and (6) sulfide mineral and secondary silicate mineral textures in both the UG-2E and UG-2 are indicative of minor, millimeter- to centimeter-scale, hydrothermal alteration. From our observations and results, we consider the UG-2E chromitite in the northern limb to be the equivalent to the UG-2 in the eastern and western limbs that has been contaminated by assimilation of Transvaal Supergroup footwall rocks during emplacement. The contamination resulted in UG-2E sulfide mineral elemental contents and platinum-group mineral types and abundances that are distinct from those of the UG-2 in the rest of the Bushveld.

Re-Os isotopic systematics and platinum group element composition of the Tagish Lake carbonaceous chondrite

2005 ◽  
Vol 69 (6) ◽  
pp. 1619-1631 ◽  
Author(s):  
Alan D. Brandon ◽  
Munir Humayun ◽  
Igor S. Puchtel ◽  
Michael E. Zolensky
Keyword(s):  
Platinum Group Element ◽  
Carbonaceous Chondrite ◽  
Element Composition ◽  
Group Element ◽  
Platinum Group

scholarly journals Platinum-group element remobilization and concentration in the Cliff chromitites of the Shetland Ophiolite Complex, Scotland

2018 ◽  
Vol 82 (3) ◽  
pp. 471-490 ◽  
Author(s):  
Brian O'Driscoll ◽  
Russell Garwood ◽  
James M. D. Day ◽  
Roy Wogelius
Keyword(s):  
Platinum Group Element ◽  
Spatial Association ◽  
Mineral Chemistry ◽  
Group Element ◽  
Ophiolite Complex ◽  
Fine Grained ◽  
Platinum Group Minerals ◽  
Alteration Processes ◽  
Melt Percolation ◽  
Platinum Group

ABSTRACTThe ~492 Ma Shetland Ophiolite Complex contains an extensive mantle section, within which numerous podiform chromitite bodies formed during melt percolation in a supra-subduction zone setting. One of the Shetland ophiolite chromitite localities has an unusual style of platinum-group element (PGE) mineralization. Specifically, the Cliff chromitite suite has relatively high (>250 ppm) Pt plus Pd, compared to other chromitites in the Shetland Ophiolite Complex. In this study, we apply petrographic observation, mineral chemistry and novel X-ray microtomography data to elucidate the petrogenesis of PGE-bearing phases at Cliff. The combined datasets reveal that the PGE at Cliff have probably been fractionated by an As-rich fluid, concentrating Pt and Ir into visible (0.1–1 µm) platinum-group minerals (PGM) such as sperrylite and irarsite, respectively. The high (>1 ppm) bulk-rock concentrations of the other PGE (e.g. Os) in the Cliff chromitites suggests the presence of abundant fine-grained unidentified PGM in the serpentinized groundmass. The spatial association of arsenide phases and PGM with alteration rims on Cr-spinel grains suggests that the high Pt and Pd abundances at Cliff result from a late-stage low-temperature (e.g. 200–300°C) hydrothermal event. This conclusion highlights the potential effects that secondary alteration processes can have on modifying and upgrading the tenor of PGE deposits.

PLATINUM GROUP ELEMENT (PGE) SYSTEMATICS OF ARC SULFIDES: A CASE STUDY FROM CUMULATES OF THE CHILAS COMPLEX, KOHISTAN ARC, PAKISTAN

2016 ◽  
Author(s):  
Ijaz Ahmad ◽  
◽  
Jeremy P. Richards ◽  
Jingao Liu ◽  
D. Graham Pearson ◽  
...  
Keyword(s):  
Platinum Group Element ◽  
Group Element ◽  
Platinum Group

scholarly journals The komatiite-mantle platinum-group element paradox

2021 ◽  
Author(s):  
Pedro Waterton ◽  
James Mungall ◽  
D. Graham Pearson
Keyword(s):  
Platinum Group Element ◽  
Group Element ◽  
Platinum Group

Variations in Composition, Texture, and Platinum Group Element Mineralization in the Lower Group and Middle Group Chromitites of the Northwestern Bushveld Complex, South Africa

2019 ◽  
Vol 114 (3) ◽  
pp. 569-590 ◽  
Author(s):  
Felix E.D. Kaufmann ◽  
Marie C. Hoffmann ◽  
Kai Bachmann ◽  
Ilya V. Veksler ◽  
Robert B. Trumbull ◽  
...  
Keyword(s):  
South Africa ◽  
Platinum Group Element ◽  
Bushveld Complex ◽  
Group Element ◽  
Middle Group ◽  
Platinum Group ◽  
Lower Group
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