| Title | Geology and gold enrichment at the Horne 5 Archean volcanogenic massive sulphide deposit, Abitibi greenstone belt, Quebec: a synthesis |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Krushnisky, A; Mercier-Langevin, P; Ross, P -S; Goutier, J; Pilote, C; Bernier, C |
| 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. 31-44, https://doi.org/10.4095/323663  Open Access |
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| 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/02; 32D/03; 32D/06; 32D/07 |
| Area | Rouyn-Noranda; Lake Osisko; Noranda Lake |
| Lat/Long WENS | -79.0531 -78.9933 48.2622 48.2361 |
| Subjects | economic geology; tectonics; geochemistry; mineralogy; Science and Technology; Nature and Environment; Archean; mineral deposits; gold; volcanogenic deposits; sulphide deposits; silver; copper; zinc;
mineral exploration; exploration guidelines; ore mineral genesis; mineralization; ore controls; mineral enrichment; lenses; bedrock geology; lithology; igneous rocks; volcanic rocks; felsic volcanic rocks; volcaniclastics; dacites; rhyodacites;
clasts; tuffs; rhyolites; basalts; andesites; lava flows; breccias; intrusive rocks; felsic intrusive rocks; mafic intrusive rocks; syenites; trondhjemites; tonalites; gabbros; diorites; diabases; structural features; faults; fault zones; mineral
assemblages; pyrite; sphalerite; chalcopyrite; host rocks; porosity; permeability; mineral zoning; thermal analyses; tectonic history; tectonic setting; volcanism; magmatism; intrusions; dykes; hydrothermal systems; fluid flow; hydrothermal
alteration; metamorphism; deformation; foliation; greenstone belts; remobilization; recrystallization; rifting; crustal thickness; lithogeochemistry; geochemical analyses; trace element analyses; major element analyses; mines; geometric analyses;
mass spectrometer analysis; Horne 5 Deposit; Abitibi Greenstone Belt; Quemont Mine; Horne Creek Fault; Andesite Fault; Horne Block; Chadbourne Mine; Precambrian |
| Illustrations | location maps; geoscientific sketch maps; 3-D models; cross-sections; plots; photographs; photomicrographs |
| Program | Targeted Geoscience Initiative (TGI-5) Gold ore systems |
| Released | 2020 06 11; 2023 03 17 |
| Abstract | The Archean Horne 5 volcanogenic massive sulphide deposit contains total resources of 172.6 t Au (5.6 Moz; 112.7 Mt at 1.53 g/t Au) with significant Ag, Cu, and Zn as by-products, one of the world's
largest volcanogenic massive sulphide-associated gold resource. The deposit consists of stacked massive to semi-massive sulphide lenses that alternate with extensive zones of disseminated and stringer sulphides enclosed within steeply dipping felsic
volcaniclastic and shallow synvolcanic intrusive units of transitional to calc-alkaline magmatic affinity. Massive sulphide clasts are locally abundant in the volcaniclastic rocks at several stratigraphic positions.
Gold is interpreted to be
synvolcanic and is spatially associated with an assemblage primarily composed of pyrite, sphalerite, and chalcopyrite. Gold distribution in the Horne 5 deposit is largely controlled by the higher porosity and permeability of select host lithologies
(fragmental felsic units), which facilitate hydrothermal fluid circulation in the subseafloor environment. The presence of felsic synvolcanic intrusions and fine-grained tuffs overlying auriferous zones also influences the distribution of the
mineralization by acting as impermeable cap rocks to ascending fluids. Although part of the mineralization formed below the seafloor, the presence of massive sulphide clasts indicates that sulphide mounds also accumulated on or close to the seafloor.
The architecture of the Horne 5 deposit is characterized by along-strike zonation of two dominant metal assemblages, i.e., Zn±Au and Cu-Au, with the Cu-Au assemblage likely representing higher temperature discharge sites. However, the original
geometry of the deposit was modified when it was tilted and transposed along the east-west foliation during deformation and metamorphism. Remobilization of metals due to metamorphism and deformation likely occurred at the micro-scale and resulted
primarily in the exsolution of gold and its associated trace elements from recrystallized pyrite.
This study provides further evidence for a major synvolcanic gold event in the southern Abitibi. It indicates that the Horne deposit is associated
with calc-alkaline felsic volcanic rocks and is consistent with the preferential association between Archean synvolcanic gold and the early phases of rifting of a thickened arc crust towards the end of the southern Abitibi greenstone belt
volcano-magmatic construction. |
| 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 | 323663 |
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