Documents disponibles écrits par cet auteur

Postmagmatic variability in ore composition and mineralogy in the T4 and T5 ore shoots at the high-grade flying fox Ni-Cu-PGE deposit, yilgarn craton, western Australia / Jane E. Collins in Economic geology, Vol. 107 N° 5 (Août 2012) 

Public ISBD [article]  in Economic geology > Vol. 107 N° 5 (Août 2012) . - pp. 859-879 Titre : Postmagmatic variability in ore composition and mineralogy in the T4 and T5 ore shoots at the high-grade flying fox Ni-Cu-PGE deposit, yilgarn craton, western Australia Type de document : texte imprimé Auteurs : Jane E. Collins, Auteur ; Stephen J. Barnes, Auteur ; Steffen G. Hagemann, Auteur Année de publication : 2012 Article en page(s) : pp. 859-879 Note générale : Economic geology Langues : Anglais (eng) Mots-clés : PGE;  high-grade  Flying  Fox  komatiite-hosted  Ni  sulfide  deposit;  Mineralogy;  Australia Index. décimale : 553 Géologie économique. Minérographie. Minéraux. Formation et gisements de minerais Résumé : The high-grade Flying Fox komatiite-hosted Ni sulfide deposit, located in the Forrestania greenstone belt of the Archean Yilgarn Craton, Western Australia, is hosted in a deformed and metamorphosed volcano-metasedimentary succession. Postmineralization events have sheared and modified the texture and composition of the original massive sulfide ore, creating up to 11 distinct ore shoots including massive, stringer/vein, and breccia sulfides composed of pyrrhotite, pentlandite, chalcopyrite, and variable abundances of pyrite ranging up to 40 vol %. Nickel and platinum group elements (PGE) tenor variations were investigated in two ore shoots, T4 and T5. All mineralization styles show considerable variability in Ni tenor. PGEs show strong linear correlations between Ir, Os, Ru, and Rh, but poor correlation between Pt, Pd, and Cu. The normalized molar proportions of Fe, Ni, and S, projected into the Fe-Ni-S ternary system, show a distinct linear trend of pyrite addition to a typical primary magmatic composition and no correlation with mineralization style. The high pyrite content present throughout the Flying Fox ore is also associated with elevated Cu and As contents and is interpreted to be primarily due to the addition of pyrite from circulating Fe-, S-, Cu-, and As-enriched fluids creating pyrite-pentlandite intergrowths. Localized mechanical segregation of pyrite, sulfidation of pyrrhotite to pyrite, and oxidation of pyrrhotite to pyrite + magnetite has also contributed to these increased pyrite contents, although to a lesser extent. The addition and segregation of pyrite has diluted the Ni tenor, with no evidence to suggest chemical mobilization of Ni. DEWEY : 553 ISSN : 0361-0128 En ligne : http://econgeol.geoscienceworld.org/content/107/5/859.short [article] Postmagmatic variability in ore composition and mineralogy in the T4 and T5 ore shoots at the high-grade flying fox Ni-Cu-PGE deposit, yilgarn craton, western Australia [texte imprimé] / Jane E. Collins, Auteur ; Stephen J. Barnes, Auteur ; Steffen G. Hagemann, Auteur . - 2012 . - pp. 859-879. Economic geology Langues : Anglais (eng) in Economic geology > Vol. 107 N° 5 (Août 2012) . - pp. 859-879 Mots-clés : PGE;  high-grade  Flying  Fox  komatiite-hosted  Ni  sulfide  deposit;  Mineralogy;  Australia Index. décimale : 553 Géologie économique. Minérographie. Minéraux. Formation et gisements de minerais Résumé : The high-grade Flying Fox komatiite-hosted Ni sulfide deposit, located in the Forrestania greenstone belt of the Archean Yilgarn Craton, Western Australia, is hosted in a deformed and metamorphosed volcano-metasedimentary succession. Postmineralization events have sheared and modified the texture and composition of the original massive sulfide ore, creating up to 11 distinct ore shoots including massive, stringer/vein, and breccia sulfides composed of pyrrhotite, pentlandite, chalcopyrite, and variable abundances of pyrite ranging up to 40 vol %. Nickel and platinum group elements (PGE) tenor variations were investigated in two ore shoots, T4 and T5. All mineralization styles show considerable variability in Ni tenor. PGEs show strong linear correlations between Ir, Os, Ru, and Rh, but poor correlation between Pt, Pd, and Cu. The normalized molar proportions of Fe, Ni, and S, projected into the Fe-Ni-S ternary system, show a distinct linear trend of pyrite addition to a typical primary magmatic composition and no correlation with mineralization style. The high pyrite content present throughout the Flying Fox ore is also associated with elevated Cu and As contents and is interpreted to be primarily due to the addition of pyrite from circulating Fe-, S-, Cu-, and As-enriched fluids creating pyrite-pentlandite intergrowths. Localized mechanical segregation of pyrite, sulfidation of pyrrhotite to pyrite, and oxidation of pyrrhotite to pyrite + magnetite has also contributed to these increased pyrite contents, although to a lesser extent. The addition and segregation of pyrite has diluted the Ni tenor, with no evidence to suggest chemical mobilization of Ni. DEWEY : 553 ISSN : 0361-0128 En ligne : http://econgeol.geoscienceworld.org/content/107/5/859.short