Artículo
Metallogenesis of Ni–Co–Fe-arsenide type mineralization in the Purísima-Rumicruz deposit, Jujuy, Argentina
López, Luciano
; Echeveste, Horacio José; Rios, Francisco Javier; Jovic, Sebastian Miguel
; Schalamuk, Bernardo Isidoro
Fecha de publicación:
06/2022
Editorial:
Pergamon-Elsevier Science Ltd
Revista:
Journal of South American Earth Sciences
ISSN:
0895-9811
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
The Purísima-Rumicruz vein system is a Ni–Co–Fe-arsenide type or Five-Element deposit located in the Cordillera Oriental, northwestern Argentina. The host rocks are Ordovician black shales of the Acoite Formation. Three vein types, were identified (a) sulfides/sulfoarsenides + carbonates ± quartz; (b) barite; and (c) crystalline quartz veins. Sulfide-carbonate veins are narrow and exhibit multi-episode infill and are NW-SE and E-W oriented. Four successive stages of mineral precipitation were established. The first stage, sulfide-rich, comprises galena, pyrite, chalcopyrite, bornite, and Zn-rich tetrahedrite-tennantite. A second stage corresponds to native silver, arsenides, Ni-sulfarsenides and pitchblende, indicative of a rise in the As/S ratio in the hydrothermal fluids. The third stage evidences a decrease in the As/S ratio with sulfide precipitation of silver sulfides, chalcocite, chalcopyrite, tetrahedrite-tennantite, bornite and millerite. Finally, a supergene event with covellite, digenite, limonite and Cu-carbonates occurred. Microthermometric studies of Stage 1 quartz yield Th between 185 and 276 °C and 5.2–12 wt% eq. NaCl. Salinities. Stage 3 calcite yield Th 110-240 °C and salinities in two ranges, 1–11 and 16.8–24 %wt. NaCl eq. The δ34S values in chalcocite and galena range between +5.8 and + 7‰, and the δ18OSMOW values from quartz, are between +6.2 and + 9.0‰. δ18OSMOW and δ13CPDB values in calcite samples range between +10.9 and +14.7‰, and −3.05 to −4.07‰, respectively. Isotope data indicate a cortical source of the fluids, probably from connate waters. Early Cretaceous rifting produced a thermal anomaly and direct faults and fractures. Deep-seated brines mixed with connate fluids of the Acoite Formation led to the formation of the Purísima-Rumicruz veins.
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Colecciones
Articulos(CCT - LA PLATA)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - LA PLATA
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - LA PLATA
Citación
López, Luciano; Echeveste, Horacio José; Rios, Francisco Javier; Jovic, Sebastian Miguel; Schalamuk, Bernardo Isidoro; Metallogenesis of Ni–Co–Fe-arsenide type mineralization in the Purísima-Rumicruz deposit, Jujuy, Argentina; Pergamon-Elsevier Science Ltd; Journal of South American Earth Sciences; 117; 6-2022; 1-13
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