2026-06-08T22:08:11Zhttps://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

Micron-to-nanoscale investigation of Cu-Fe-Ni sulfide inclusions within laurite (Ru, Os)S2 from chromitites González Jiménez , José María González Pérez, Igor Plissart, Gaëlle Ferreira García, Amira Rosa Schettino, Erwin Yesares Ortiz, María Dolores Schilling, Manuel E. Corgne, Alexandre Gervilla, Fernando 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. 2025-04-08T17:14:36Z 2025-04-08T17:14:36Z 2025-04-08T17:14:36Z 2024-06-26 journal article https://hdl.handle.net/20.500.14352/119409 0026-4598 10.1007/s00126-024-01285-0 1432-1866 eng NANOMET PID2022-138768OB-I00 PRE2019-088262 FONDECYT Project 1211820 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 http://creativecommons.org/licenses/by/4.0/ open access Attribution 4.0 International Springer