In-situ geochemistry of sulfides in highly metasomatized mantle xenoliths from Kerguelen, southern Indian Ocean

Delpech, Guillaume; Lorand, Jean Pierre; Grégoire, Marilaure; Cottin, Jean-Yves; O’Reilly, Suzanne Y.

doi:10.1016/j.lithos.2012.07.018

Cited by 54 publications

(31 citation statements)

References 81 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The absence of Te-bearing microphases and the lack of any correlation between Te and elevated Cu or Pd concentrations (c.f. Delpech et al, 2012) further confirm the Te-poor nature of all Loch Roag BMS.…”

Section: Accepted M Manuscriptsupporting

confidence: 69%

“…These textural associations are consistent with an origin by melt infiltration or metasomatism inferred from the IPGE-poor and PPGE-and Re-rich geochemistry outlined above. However Group A BMS lack the systematic enrichment in Os over the other IPGE (reflected by both (Os/Ir) N >1), and consistently lack the low Se concentrations (< 100 ppm), high S/Se (> 3500 up to 10000) and coupled enrichment in Te and Pd that have been suggested to characterise very volatile-rich metasomatism and vapour transport of Os, Pd, Au, Re and S (e.g., Alard et al, 2011;Delpech et al, 2012). The textural appearance of the sulphide minerals forming Group A BMS (in addition to their interstitial setting; Table 5) would indicate a metasomatic origin (e.g., Lorand & Luguet, 2016;Aulbach et al, 2016).…”

Section: Accepted M Manuscriptmentioning

confidence: 95%

“…The textural appearance of the sulphide minerals forming Group A BMS (in addition to their interstitial setting; Table 5) would indicate a metasomatic origin (e.g., Lorand & Luguet, 2016;Aulbach et al, 2016). These superficially look to be akin to 'Type-2' BMS documented in Alard et al (2000), but the absence of systematic and coupled enrichment in Os, S and Pd for Group A BMS suggests that these are compositionally unlike such BMS proposed to have formed by vapour transport processes (e.g., Alard et al, 2011;Delpech et al, 2012) and therefore a different metasomatic agent may be envisaged, with high S-content at sulphide saturation (e.g., Aulbach et al, 2016).…”

Section: Accepted M Manuscriptmentioning

confidence: 98%

“…or CO 2 -rich fluids during mantle metasomatism in an off-craton environment (Delpech et al, 2012;Lorand et al, 2013;Lorand & Luguet, 2016).…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

See 3 more Smart Citations

Paradoxical co-existing base metal sulphides in the mantle: The multi-event record preserved in Loch Roag peridotite xenoliths, North Atlantic Craton

Hughes

McDonald

Loocke

et al. 2017

Lithos

View full text Add to dashboard Cite

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractThe role of the subcontinental lithospheric mantle as a source of precious metals for mafic magmas is contentious and, given the chalcophile (and siderophile) character of metals such as the platinumgroup elements (PGE), Se, Te, Re, Cu and Au, the mobility of these metals is intimately linked with that of sulphur. Hence the nature of the host phase(s), and their age and stability in the subcontinental lithospheric mantle may be of critical importance. We investigate the sulphide mineralogy and sulphide in situ trace element compositions in base metal sulphides (BMS) in a suite of spinel lherzolite mantle xenoliths from northwest Scotland (Loch Roag, Isle of Lewis). This area is situated on the margin of the North Atlantic Craton which has been overprinted by a Palaeoproterozoic orogenic belt, and occurs in a region which has undergone magmatic events from the Palaeoproterozoic to the Eocene.We identify two populations of co-existing BMS within a single spinel lherzolite xenolith (LR80) and which can also be recognised in the peridotite xenolith suite as a whole. Both populations consist of a mixture of Fe-Ni-Cu sulphide minerals, and we distinguished between these according to BMS texture, petrographic setting (i.e., location within the xenolith in terms of 'interstitial' or within feldspar-spinel symplectites, as demonstrated by X-ray Computed Microtomography) and in situ trace element composition. Group A BMS are coarse, metasomatic, have low concentrations of total PGE (< 40 ppm) and high (Re/Os) N (ranging 1 to 400). Group B BMS strictly occur within symplectites of spinel and feldspar, are finer-grained rounded droplets, with micron-scale PtS (cooperite), high overall total PGE concentrations (15-800 ppm) and low (Re/Os) N ranging 0.04 to 2. Group B BMS sometimes coexist with apatite, and both the Group B BMS and apatite can preserve rounded micron-scale Ca-carbonate inclusions indicative of sulphide-carbonate-phosphate immiscibility. This carbonate-phosphate metasomatic association appears to be important in forming PGE-rich sulphide liquids, although the precise mechanism for this remains obscure. As a consequence of their position within the symplectites, Group B BMS are particularly vulnerable to being incorporated in ascending A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTmantle-derived magmas (either by melting or physical entrainment). Based on the cross-cutting relationships of the symplectites, it is possible to in...

show abstract

Section: Accepted M Manuscriptsupporting

confidence: 69%

Section: Accepted M Manuscriptmentioning

confidence: 95%

Section: Accepted M Manuscriptmentioning

confidence: 98%

“…or CO 2 -rich fluids during mantle metasomatism in an off-craton environment (Delpech et al, 2012;Lorand et al, 2013;Lorand & Luguet, 2016).…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

See 2 more Smart Citations

Paradoxical co-existing base metal sulphides in the mantle: The multi-event record preserved in Loch Roag peridotite xenoliths, North Atlantic Craton

Hughes

McDonald

Loocke

et al. 2017

Lithos

View full text Add to dashboard Cite

show abstract

“…The interpretation of BMS produced metasomatically through sulfidation reactions Delpech et al 2012) is based on their morphology (high dihedral angle and sharp-straight BMS grain contours), textural relationships (associated with carbonates), and mineralogy (low Cu/Cu + Ni (< 0.1) and low-Ni, pyrrhotite-dominated assemblages; Lorand et al 2013). These BMS are always derived from small fractions of alkali melts that have experienced extensive reaction with the host peridotite in the uppermost SCLM (Menzies and Hawkesworth 1987;Bedini et al 1997;Alard et al 2011).…”

Section: Peridotite-hosted Sulfidesmentioning

confidence: 99%