Mineral systems with IOCG and affiliated deposits: Part 2 - Geochemical footprints - BRGM - Bureau de recherches géologiques et minières Accéder directement au contenu
Chapitre D'ouvrage Année : 2022

Mineral systems with IOCG and affiliated deposits: Part 2 - Geochemical footprints

Résumé

Regional iron oxide and alkali-calcic alteration systems generate a wide variety of ore deposits, including iron oxide apatite (IOA), iron oxide copper-gold (IOCG), iron oxide Co, Bi, REE or U, skarn, and albitite-hosted uranium and Au-Co ± U deposits. The Great Bear magmatic zone (Canada), Cloncurry district and Olympic Copper-Gold Province (Australia) are used as examples to illustrate the lithogeochemical footprints of these mineralizing hydrothermal systems. Plotting metal contents on a diagram that discriminates the iron oxide and alkali-calcic alteration facies (AIOCG plot) highlights the coupling of V, Sc, Ni ± Pb ± Zn with Ca and Fe, as Facies 1 (Na) alteration evolves to Facies 2 (high-temperature Ca-Fe) alteration and IOA mineralization. In metasedimentary rocks, propagation of fluid-rock reactions towards Facies 3 forms a transitional Facies 2–3 (high-temperature Ca-K-Fe) alteration that is marked by enrichment in cobalt and gold and onset of copper precipitation. Au-Co-Bi ± Cu deposits with iron-rich end-members are associated with the precipitation of As, Bi and W (e.g. NICO deposit, Great Bear). Facies 3 (high-temperature K-Fe) alteration containing biotite may also be rich in cobalt and arsenic (Ernest Henry, Cloncurry), whereas Facies 3 alteration in which K-feldspar prevails over biotite is associated with precipitation of Ag, Au, Bi, Cu, Mo, REE, ± U and locally Ni. Facies 4 (K-felsite) alteration is either barren or locally enriched in thorium. Alternatively, in carbonate units and carbonate-altered units, zones of K-skarn may form and host polymetallic mineralization. Facies 5 (low-temperature K-Fe to Ca-Mg-Fe) alteration is associated with the formation of mineralized zones containing variable proportions of Ag, Au, Cd, Cu, Mo, Pb, REE, U and Zn. The sequence of alteration facies records the pathways followed by metals during deposit formation within the system. The resulting footprints provide mappable criteria in outcrop and drill core for mineral potential assessments and facilitate vectoring to IOCG and affiliated mineralization, including variants enriched in critical metals.
2022_Corriveau_part-2_p1-2.pdf (3.99 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-04417924 , version 1 (25-01-2024)

Identifiants

  • HAL Id : hal-04417924 , version 1

Citer

Louise Corriveau, Jean-François F Montreuil, Olivier Blein, Kathy Ehrig, Eric G Potter, et al.. Mineral systems with IOCG and affiliated deposits: Part 2 - Geochemical footprints. Corriveau, L.; Potter, E.G.; Mumin, A.H. Mineral systems with iron oxide copper-gold (IOCG) and affiliated deposits, 52, Geological Association of Canada, pp.159-204, 2022, 978-1-897095-96-6. ⟨hal-04417924⟩

Collections

BRGM
12 Consultations
2 Téléchargements

Partager

Gmail Facebook X LinkedIn More