RT Journal Article
T1 PGE-Ni-Cu sulphide segregation by interaction of basaltic melt and peridotite xenoliths of the Catalan Volcanic Zone (Spain)
A1 Roquet, Miguel
A1 Schettino, Erwin
A1 Campeny, Marc
A1 González Jiménez, José María
A1 Grégoire, Michel
A1 Piña García, Rubén
A1 Leisen, Mathieu
A1 Proenza Fernández, Joaquin Antonio
A1 Laurent, Oscar
A1 Planagumà, Llorenç
A1 Llovet, Xavier
AB Spinel lherzolite xenoliths from the Sant Corneli volcano (Catalan Volcanic Zone, NE Spain) carry the geochemical imprint of melt/rock reaction events that have affected the subcontinental lithospheric mantle (SCLM) beneath the northeastern Iberian margin. Trace element signatures of clinopyroxene indicate that this volume of the SCLM initially experienced low degrees (F = 8 %) of partial melting, followed by extensive refertilization by alkaline silicate melts undergoing chromatographic fractionation while percolating through the mantle peridotites. Furthermore, the presence of interstitial sulphide-bearing silicate glass, as well as secondary coronitic rims around mantle minerals, records the melt/rock reaction product associated with the infiltration of the host alkaline basalts while erupting to the surface. Abundant irregular/blocky sulphides located within the interstitial glass patches are comprised of myrmekitic intergrowths of pentlandite ± bornite ± chalcopyrite, suggesting their derivation from immiscible droplets of Fe-Ni-Cu sulphide melt transported by the host alkaline basalts. The variable chondrite-normalized platinum-group element (PGE) systematics and chalcogenes (Se, Te, As, Bi and Sb) abundances of these sulphides track two distinct transport mechanisms for their parental sulphide melts: 1) by unmixing of Ni-Cu-rich sulphide liquid in alkaline basalts attaining sulphide-saturation while interacting with the peridotite xenoliths, and 2) by mechanical transport of immiscible droplets of Ni-Cu-rich sulphide liquid originally extracted by residual monosulphide solid solution undergoing incongruent melting in their mantle source. In addition, many sulphides have PGE abundances that cannot be explained solely by solid-melt chemical partition coefficients but that were likely influenced by the mechanical entrapment, or early-magmatic segregation, of pre-existing PGE-rich nanoparticles or nanomelts. The geochemical signal of these mineral nanoparticles may significantly influence sulphides PGE distribution, sometimes resulting in pronounced positive anomalies in Irsingle bondRh, Au, or Rusingle bondRh, along with negative anomalies in Pt.
PB Elsevier
SN 0024-4937
YR 2024
FD 2024-12-01
LK https://hdl.handle.net/20.500.14352/110041
UL https://hdl.handle.net/20.500.14352/110041
LA eng
NO Roquet, Miguel, et al. «PGE-Ni-Cu Sulphide Segregation by Interaction of Basaltic Melt and Peridotite Xenoliths of the Catalan Volcanic Zone (Spain)». Lithos, vol. 488-489, diciembre de 2024, p. 107820, https://doi.org/10.1016/j.lithos.2024.107820
NO MCIN/AEI/10.13039/50110001133
NO European Union
DS Docta Complutense
RD 9 abr 2025