| Title | Fingerprinting ore processes in orogenic auriferous systems: insights into metallogenic and exploration implications from argillite-hosted iron sulphide nodules from the Timmins-Matheson gold
corridor |
| Download | Download (whole publication) |
| |
| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Pilote, J -L; Jackson, S E ; Mercier-Langevin, P; Dubé, B; Lawley, C J M; Petts, D C; Yang, Z; van Hees, E; Rhys, D |
| 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. 165-178, https://doi.org/10.4095/323675  Open Access |
| 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 | Ontario |
| NTS | 31M/13; 32D/04; 32D/05; 32D/12; 32D/13; 32E/04; 41P/13; 41P/14; 41P/15; 41P/16; 42A; 42H/01; 42H/02; 42H/03; 42H/04 |
| Area | Timmins; Matheson; Matachewan |
| Lat/Long WENS | -81.5500 -79.6500 49.2167 47.8333 |
| Subjects | economic geology; tectonics; geochemistry; Science and Technology; Nature and Environment; mineral deposits; gold; sulphide deposits; epigenetic deposits; mineral exploration; exploration guidelines;
ore mineral genesis; mineralization; ore controls; mineral enrichment; metallogeny; geological history; diagenesis; tectonic setting; tectonic history; deformation; metamorphism; strain; hydrothermal systems; hydrothermal alteration; intrusions; host
rocks; bedrock geology; lithology; metamorphic rocks; metasedimentary rocks; carbonate rocks; argillites; volcanic-sedimentary belts; igneous rocks; intrusive rocks; structural features; faults; fault zones; nodules; sulphides; iron; concretions;
pyrite; zoning; textural analyses; mass spectrometer analysis; geochemical analyses; trace element analyses; thallium geochemistry; statistical analyses; correlations; isotopic studies; Archean; Neoarchean; Timmins-Porcupine Gold Camp; Superior
Province; Abitibi Greenstone Belt; Kidd-Munro Assemblage; Tisdale Assemblage; Porcupine Assemblage; Timiskaming Assemblage; Blake River Assemblage; Deloro Assemblage; Stoughton-Roquemaure Assemblage; Pacaud Assemblage; Destor-Porcupine Fault Zone;
Pipestone Fault; Bell Creek Deposit; Bradshaw Deposit; Precambrian |
| Illustrations | geoscientific sketch maps; photomicrographs; photographs; plots; tables; profiles |
| Program | Targeted Geoscience Initiative (TGI-5) Gold ore systems |
| Released | 2020 06 11 |
| Abstract | Orogenic Au deposits of the world-class Timmins-Porcupine Au camp in Abitibi and its surroundings are commonly hosted by carbonaceous to non-carbonaceous argillite sequences, which contain Au-rich (less
than or equal to10 ppm Au) nodules and concretions; two features widely considered to be diagenetic, but can be equivocal in some highly strained and hydrothermally altered zones. Hence, the goals of this research activity are to (1) fingerprint
pyrite of diagenetic or epigenetic origin, (2) constrain factors that control Au uptake in diagenetic pyrite, and (3) determine if early Au enrichment fundamentally influences overprinting orogenic Au mineralization. Pyrite nodules and concretions
are generally composed of two textural domains: a core and a rim. The pyrite rims exhibit much more textural complexity than the pyrite cores. Multivariate analysis of trace element data derived from laser ablation-inductively coupled plasma-mass
spectrometry reveal a clear geochemical distinction between epigenetic textures (granoblasts, porphyroblasts, idiomorphic overgrowths) and nodules/concretions. In the Timmins-Matheson region, disparate pyrite textures can be discriminated simply by
the abundance of thallium. Nodules and concretions also show geochemical attributes that are inherited from the composition of the rock assemblage in which they form. Regardless of their host rocks, the core and rim of the nodules possess different
but systematic geochemical signatures, which were constrained with the help of multivariate statistics; Ni, As, Se, Ag, Sb, Au, Pb, and Bi tend to concentrate into the core, whereas Mo and Tl (±Mn) tend to concentrate into the rim. In situ Fe isotope
analyses of three pyrite nodules reveal intra-grain variations in delta-56Fe values that range from -3.11 to 0.74 per mille, with 30% of the values < -2.5 per mille which has, in the literature to date, been recorded only in Archean diagenetic pyrite
in black shale. The results contribute to a framework that helps improving our interpretation of the genesis of pyrite nodules in deformed and metamorphosed sedimentary rocks, which will ultimately minimize uncertainties related to the interpretation
of ore-forming processes. |
| 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 | 323675 |
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