| Title | Lithological and tectonic controls on banded iron formation-associated gold at the Amaruq deposit, Churchill Province, Nunavut, and implications for exploration |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Valette, M; De Souza, S; Mercier-Langevin, P; Côté-Mantha, O; Simard, M; Wodicka, N ; McNicoll, V J; Barbe, P |
| 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. 251-266, https://doi.org/10.4095/326042  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 |
| Related | This publication is related to Geological setting of the 5.2
Moz Au Amaruq banded iron formation-hosted gold deposit, Churchill Province, Nunavut |
| File format | pdf |
| Province | Nunavut |
| NTS | 66H/07 |
| Area | Whale Lake; Mammoth Lake; Kivalliq Region |
| Lat/Long WENS | -96.7500 -96.6667 65.4333 65.3833 |
| Subjects | economic geology; tectonics; structural geology; igneous and metamorphic petrology; geochemistry; Science and Technology; Nature and Environment; mineral deposits; gold; strata-bound deposits;
replacement deposits; ore mineral genesis; mineralization; ore controls; modelling; mineral exploration; exploration guidelines; tectonic setting; tectonic history; deformation; folding; metamorphism; greenschist facies; orogenesis; shearing; strain;
fabric analyses; veins; sulphides; hydrothermal systems; hydrothermal alteration; intrusions; bedrock geology; lithology; volcano-sedimentary strata; sedimentary rocks; iron formations; cherts; greywackes; argillites; pelites; igneous rocks; volcanic
rocks; basalts; komatiites; intrusive rocks; diorites; ultramafic rocks; mafic rocks; metamorphic rocks; structural features; folds; shear zones; faults; faults, normal; structural analyses; structural trends; fold geometry; structural domains;
mineral assemblages; petrographic analyses; host rocks; whole rock geochemistry; x-ray diffraction analyses; core samples; graphite; silicates; Archean; Canadian Shield; Churchill Province; Rae Craton; Amaruq Deposit; Woodburn Lake Group; Rumble
Assemblage; Whale Tail Zone; IVR Zone; Snow Island Suite; Woodburn Lake Greenstone Belt; Rae Domain; Neoarchean; Paleoproterozoic; Precambrian; Proterozoic |
| Illustrations | location maps; geoscientific sketch maps; stratigraphic columns; geochemical plots; ternary diagrams; tables; photographs; photomicrographs; cross-sections |
| Program | Targeted Geoscience Initiative (TGI-5) Gold ore systems |
| Released | 2020 06 11; 2023 03 17 |
| Abstract | The Amaruq gold deposit in Nunavut is underlain by the Neoarchean (ca. 2.73-2.63 Ga) supracrustal rocks of the Woodburn Lake group, within the Rae Craton of the Churchill Province. The mineralized zones
are hosted in polydeformed, upper greenschist-facies banded iron formation and volcanic and sedimentary rocks of the Rumble assemblage. The assemblage includes rocks of contrasting rheology and geochemistry, such as greywacke, chert, graphitic
argillite, komatiite, and komatiitic basalt, which have been deformed and metamorphosed in the Archean and during subsequent Paleoproterozoic orogenesis. In the Amaruq area, several generations of structures are recognized: 1) tight and isoclinal F1
folds and D1 shear zones; and 2) upright and isoclinal northeast-plunging F2 folds and associated D2 shear zones that host the bulk of gold mineralization. Progressive strain accommodation during D2 deformation led to the development of
northwest-verging overthrust and recumbent F2 folds. Subsequent deformation consists of open to chevron-style, northeast- and southwest-plunging F3 folds, and north- and east-striking D4 and D5 normal faults and shear zones, respectively. The two
principal mineralized areas of the Amaruq deposit, the Whale Tail and IVR, comprise contrasting styles, geometry, and distribution of ore zones in distinct structural domains. The Whale Tail area is primarily characterized by stratabound and locally
discordant disseminated to semi-massive pyrrhotite-arsenopyrite-gersdorffite replacement-style orebodies in chert-poor silicate-facies iron formation, and by 'silica flooding' zones associated with arsenopyrite-löllingite-pyrrhotite in chert-rich
silicate-facies iron formation. The IVR area occurs in an overturned F2 fold-hinge zone and consists predominantly of shallowly southeast-dipping quartz±carbonate veins that cut the host volcano-sedimentary sequence. Proximal alteration is
characterized by variable amounts of Ca-amphibole-feldspar-epidote-muscovite-biotite-carbonate. Petrographic relationships of metamorphic and auriferous sulphide minerals indicate that prograde upper greenschist metamorphism is coeval with D2
deformation. Native gold was in part exsolved from prograde löllingite during retrograde metamorphism to lower greenschist facies associated with D3 deformation. The crosscutting relationships between the contrasting ore styles suggest a protracted,
multiphase hydrothermal history. The age and relative timing of the gold mineralization represent key issues that are being addressed to help in the development of improved exploration models for banded iron formation-hosted/associated gold deposits
in the Churchill Province and other Archean terranes. |
| 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 | 326042 |
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