| Title | Interrogating the composition and genesis of argillite-hosted pyrite nodules at the LaRonde Penna gold-rich volcanogenic massive sulphide deposit, Abitibi, Quebec: insights into metallogenic
implications |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Pilote, J -L; Mercier-Langevin, P; Jackson, S E ; Dubé, B; Yang, Z; Lawley, C J M;
Petts, D C; Layne, G D; Piercey, S J |
| Source | Targeted Geoscience Initiative 5: contributions to the understanding of Canadian gold systems; by Mercier-Langevin, P (ed.); Lawley, C J M (ed.); Castonguay, S (ed.); Geological Survey of Canada, Open File 8712, 2020 p. 75-91, https://doi.org/10.4095/323666  Open Access |
| Image |  |
| Year | 2020 |
| Publisher | Natural Resources Canada |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| Related | This publication is contained in Targeted Geoscience
Initiative 5: contributions to the understanding of Canadian gold systems |
| File format | pdf |
| Province | Quebec |
| NTS | 32D/01; 32D/02; 32D/07; 32D/08 |
| Area | Abitibi |
| Lat/Long WENS | -78.6000 -78.4000 48.3000 48.2167 |
| Subjects | economic geology; tectonics; mineralogy; geochemistry; Nature and Environment; Science and Technology; mineral deposits; gold; zinc; silver; copper; lead; volcanogenic deposits; sulphide deposits;
mineral exploration; exploration guidelines; ore mineral genesis; mineralization; ore controls; metallogeny; host rocks; pyrite nodules; mineralogical analyses; textures; inclusions; mineral zoning; mass spectrometer analysis; diagenesis; models;
bedrock geology; lithology; sedimentary rocks; argillites; igneous rocks; volcanic rocks; volcaniclastics; tuffs; dacites; rhyodacites; rhyolites; andesites; basalts; intrusive rocks; diabases; structural features; faults; fault zones; joints;
veinlets; veins; quartz veins; lenses; alteration; tectonic setting; tectonic evolution; deformation; metamorphism; schistosity; magmatism; volcanism; intrusions; sills; dykes; strain; hydrothermal systems; mineral enrichment; alteration; mineral
assemblages; quartz; garnet; biotite; muscovite; albite; pyrrhotite; rutile; titanite; geochemical analyses; trace element analyses; major element analyses; statistical analyses; stable isotope studies; sulphur; Archean; Doyon-Bousquet-LaRonde Mining
Camp; LaRonde Penna Deposit; Abitibi Greenstone Belt; Blake River Group; Bousquet Formation; Cadillac Group; Precambrian |
| Illustrations | geoscientific sketch maps; cross-sections; photographs; photomicrographs; schematic diagrams; tables; plots; geochemical profiles |
| Program | Targeted Geoscience Initiative (TGI-5) Gold ore systems |
| Released | 2020 06 11; 2023 03 17 |
| Abstract | This study investigates pyrite nodules hosted in argillite horizons within (Zn-Ag-Au-Cu±Pb) massive sulphide ore of the 20N Zn zone at the LaRonde Penna Au-rich volcanogenic massive sulphide deposit,
Abitibi greenstone belt, Quebec. Two pyrite nodules are examined in detail: LA-001 and LA-002. These nodules are spherical and oblate spheroidal in shape and display similar textures, including a core (zone 1) composed of fine, equigranular grains
with variable amounts of silicate-carbonate inclusions; a rim (zones 2a to c) that varies from inclusion-poor to -rich and consists of equigranular to radially oriented, acicular pyrite grains; and a thin layer of idiomorphic pyrite overgrowth that
surrounds the nodules (zone 3). Sulphide inclusions in nodule LA-001 consist predominantly of sphalerite, whereas sulphide inclusions in nodule LA-002 include an assemblage of sphalerite, Zn-bearing stannite (Cu2(Fe,Zn)SnS4), and galena, all of which
occur also in the surrounding massive sulphide ore. In nodule LA-002, sphalerite is intimately associated with stannite, and together they are preferentially concentrated along both the concentric zones of the inclusion-rich section of the rim (zone
2b) and within the radially bladed rim (zone 2c), parallel to blade elongation. Whereas textures are similar in the two nodules, compositional maps generated by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) reveal important
distinctions in element distribution patterns for inclusion-partitioned elements (Cu, Zn, Sn, Pb, Bi), which reflect the mineralogy and bulk abundances for lattice-bound elements (Ni, As, Au). Gold is mainly concentrated in the fine-grained cores,
but in different amounts in LA-001 (average of 0.38 ppm Au; n = 6918) and LA-002 (average of 1.04 ppm Au; n = 10,539). Nickel and As values in LA-001 are respectively 10 and 3 times greater than in LA-002. In both nodules, Ni is enriched in the rim
relative to the core. The pyrite nodules have in situ delta-34S values (secondary ion mass spectrometry analyses) that range from -0.8 to +5.0 per mille (average +2.1 per mille, n = 50), with the core showing slightly lighter values than the rim.
Based on these results, the nodules (zones 1 and 2) are interpreted to have formed by diagenetic processes and the presence of stannite, sphalerite, and galena (enrichment in Zn, Sn, Cu, and Pb) is likely the expression of a previously hydrothermally
enriched sediment rather than a direct hydrothermal contribution during crystal growth. While more work is needed, the composition of pyrite nodules could potentially be used as vectors toward syngenetic mineralization. |
| Summary | (Plain Language Summary, not published)
The main objective of phase 5 (2015-2020) of Natural Resources Canada and Geological Survey of Canada's Targeted Geoscientific Initiative (TGI) program
was to generate new knowledge, methodologies and models to enhance the exploration industry's ability to detect buried ore deposits. This synthesis volume contains 20 individual papers that discuss craton to deposit-scale characteristics of
auriferous deposits, plus some support material pertaining to the TGI-5 Gold project. |
| GEOSCAN ID | 323666 |
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