| Title | New U-Pb geochronology from the Blake River Group, Abitibi Subprovince, Québec: implications for geological interpretations and base metal exploration |
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| Author | McNicoll, V; Goutier, J; Dubé, B; Mercier-Langevin, P; Ross, P; Dion, C; Monecke, T; Legault, M; Percival, J; Gibson, H |
| Source | Archean volcanism, magmatism and ore deposits; by Mercier-Langevin, P (ed.); Hannington, M (ed.); Gibson, H (ed.); Houlé, M (ed.); Dubé, B (ed.); Monecke, T (ed.); Goutier, J (ed.); Economic geology and
the bulletin of the Society of Economic Geologists vol. 109, no. 1, 2014 p. 27-59, https://doi.org/10.2113/econgeo.109.1.27 |
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| Year | 2014 |
| Alt Series | Earth Sciences Sector, Contribution Series 20110274 |
| Publisher | Society of Economic Geologists |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Quebec; Ontario |
| NTS | 32D |
| Area | Rouyn-Noranda |
| Lat/Long WENS | -80.0000 -78.5000 49.0000 48.0000 |
| Subjects | geochronology; metallic minerals; uranium lead dates; volcanic rocks; mineral deposits; mineralization; Archean; volcanic rocks; plutonic rocks; volcanogenic deposits; sulphide deposits; Blake River
Group; Abitibi greenstone belt; Horne mine; Quemont deposit; Fabie deposit; Millenbach mine; Amulet mine; Bousquet Formation; LaRonde Penna mine; Bousquet 2-Dumagami deposit; Precambrian |
| Illustrations | geological sketch maps |
| Program | Targeted Geoscience Initiative (TGI-3), 2005-2010 Abitibi TGI-3 |
| Program | Targeted Geoscience Initiative (TGI-4) Volcanogenic Massive Sulfide Ore Systems |
| Program | Targeted Geoscience Initiative (TGI-4) Gold Ore Systems |
| Released | 2013 11 19 |
| Abstract | The 2704 to 2695 Ma Blake River Group in the southern Abitibi greenstone belt comprises a well preserved submarine volcanic sequence that hosts a large number of VMS and important Au-rich VMS deposits,
including the world-class Horne and LaRonde-Penna deposits. Establishing precise chronostratigraphic control on the VMS deposits within the Blake River Group is critical because numerous distinct events took place within a period of 9 m.y. Nineteen
new high-precision U-Pb ages temporally constrain the host rocks of many polymetallic VMS deposits and associated synvolcanic intrusions, demonstrating that these VMS deposits formed throughout the protracted volcanic evolution of the entire group.
Ages on host rocks of the Horne (2702.2 ± 0.9 Ma), Quemont (2702.0 ± 0.8 Ma), and Fabie (2701.9 ± 0.9 Ma) deposits reveal that they are among the oldest VMS deposits in the Blake River Group. The giant Horne Au-rich VMS deposit had already formed
when the Cu-Zn deposits of the Noranda mine sequence, including Millenbach and Amulet, were generated at ~2698 Ma and is thus unrelated, consistent with its different volcanological setting and metal content. Large Au-rich VMS deposits of the
Bousquet Formation, including LaRonde Penna and Bousquet 2-Dumagami, were formed at 2698 to 2697 Ma and are distinctly younger than the Horne and Quemont deposits. There were, therefore, two major time-stratigraphic intervals within the Blake River
Group that were favorable for the formation of Au-rich VMS deposits. Rhyolite hosting the large Bouchard-Hébert VMS deposits yielded an age of 2695.8 ± 0.8 Ma.
Important mineralizing events in the Blake River Group occur at ca. 2-m.y. intervals
apart and are associated with major magmatic episodes. Recognition of specific time-stratigraphic intervals for different styles of mineralization and geologic settings is essential to improve exploration models within the Blake River Group and for
similar volcanic assemblages elsewhere in the Archean. |
| GEOSCAN ID | 289583 |
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