2026-06-08T22:08:14Zhttps://docta.ucm.es/rest/oai/request

oai:docta.ucm.es:20.500.14352/1194092025-04-09T00:14:56Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc González Jiménez , José María author González Pérez, Igor author Plissart, Gaëlle author Ferreira García, Amira Rosa author Schettino, Erwin author Yesares Ortiz, María Dolores author Schilling, Manuel E. author Corgne, Alexandre author Gervilla, Fernando author 2024-06-26 This paper provides a top-down nanoscale analysis of Cu-Ni-Fe sulfide inclusions in laurite from the Taitao ophiolite (Chile) and the Kevitsa mafic-ultramafic igneous intrusion (Finland). High-resolution transmission electron microscopy (HRTEM) reveal that Cu-Ni-Fe sulfide inclusions are euhedral to (sub)-anhedral (i.e., droplet-like) and form single, biphasic or polyphasic grains, made up of different polymorphs, polytypes and polysomes even within a single sulfide crystal. Tetragonal (I4 d) and cubic (F 3m) chalcopyrite (CuFeS2) host frequent fringes of bornite (Cu5FeS4; cubic F3m and/or orthorhombic Pbca) ± talnakhite (Cu9(Fe, Ni)8S16; cubic I3m) ± pyrrhotite (Fe1 − xS; monoclinic C2/c polytype 4C and orthorhombic Cmca polytype 11C) ± pentlandite ((Ni, Fe)9S8; cubic Fm3m). Pentlandite hosts fringes of pyrrhotite, bornite and/or talnakhite. Laurite and Cu-Fe-Ni sulfide inclusions display coherent, semi-coherent and incoherent crystallographic orientation relationships (COR), defined by perfect edge-to-edge matching, as well as slight (2–4º) to significant (45º) lattice misfit. These COR suggest diverse mechanisms of crystal growth of Cu-Fe-Ni sulfide melt mechanically trapped by growing laurite. Meanwhile, the mutual COR within the sulfide inclusions discloses: (1) Fe-Ni-S melt solidified into MSS re-equilibrated after cooling into pyrrhotite ± pentlandite, (2) Cu-Ni-Fe-S melts crystallized into the quaternary solid solution spanning the compositional range between heazlewoodite [(Ni, Fe)3±xS2] (Hzss) and ISS [(Cu1±x, Fe1±y)S2]. Additionally, nanocrystallites (50–100 nm) of Pt-S and iridarsenite (IrAsS) accompanying the sulfide inclusions spotlight the segregation of PGE-rich sulfide and arsenide melt earlier and/or contemporarily to laurite crystallization from the silicate magmas. Cobaltite (CoAsS)-gersdorffite (NiAsS) epitaxially overgrown on laurite further supports the segregation of arsenide melts at early stages of chromitite formation. González-Jiménez, J. M., González-Pérez, I., Plissart, G., Ferreira, A. R., Schettino, E., Yesares, L., Schilling, M. E., Corgne, A., & Gervilla, F. (2025). Micron-to-nanoscale investigation of Cu-Fe-Ni sulfide inclusions within laurite (Ru, os)S2 from chromitites. Mineralium Deposita, 60(2-3), 581-604. https://doi.org/10.1007/s00126-024-01285-0 0026-4598 10.1007/s00126-024-01285-0 https://hdl.handle.net/20.500.14352/119409 1432-1866 https://doi.org/10.1007/s00126-024-01285-0 https://link.springer.com/article/10.1007/s00126-024-01285-0 Micron-to-nanoscale investigation of Cu-Fe-Ni sulfide inclusions within laurite (Ru, Os)S2 from chromitites