Kewagama group
Stratigraphic label: [narc]kw
Map symbol: nAkw

First published: 17 juillet 2018
Last modified:






















Translation of original French



Informal subdivision(s)
Numbering does not necessarily reflect the stratigraphic position.
Author:Gunning, 1936
Reference section: 
Type area:NTS sheets 32D07, 32D08 and 32C05
Geological province:Superior Province
Geological subdivision:Abitibi Subprovince
Lithology:Sedimentary rocks


Related unit(s)
  • Kewagama Group




The Kewagama Group was first mentioned in the reports and 1:12,000 scale geological maps of Gunning (1936) and Gunning and Ambrose (1939, 1940). These authors were the first to present a consistent lithostratigraphic subdivision of the Cadillac-Malartic region. Their work led them to divide the stratigraphic pile known in the 1940s into two sedimentary sequences, the Kewagama and Cadillac groups, and two volcanic sequences, the Malartic and Blake River groups. At that time, the Kewagama Group included the current Kewagama and Pontiac groups. The Blake River Group included the current Blake River and Piché groups. Latulippe (1976), Dimroth et al. (1982), Imreh (1984, 1991) and Pilote et al. (2009) subsequently resumed the work of Gunning and Ambrose (1939, 1940) and advocated the use of the expression “Kewagama Formation”, which then referred only to sedimentary lithologies located between the Rivière-Héva and Dubuisson localities (sheets 32D01, 32D07 and 32D08).

The Mont-Brun Formation (nAmn) represents the central strip, which had historically been assigned to the Kewagama Group for several decades. The Caste Formation (nAlc), formerly known as the “Caste Group” (Dimroth et al., 1973; Dimroth and Rocheleau, 1979) or “Lac Caste Formation” (Dimroth et al., 1982), represents three lenses of tectonically segmented sedimentary rocks trapped between volcanics of the Kinojévis and Malartic groups. Based on similarities between three different sedimentary basins of similar ages in the Malartic, Cadillac and Rouyn-Noranda regions, named the Rivière Dufresnoy, Mont-Brun and Caste formations respectively, Goutier (1997) proposes to group them under the name Kewagama Group.



The various units of the Kewagama Group consist of turbiditic sedimentary rocks deposited in deep basins located on the periphery of volcanic centres. Specifically, the Kewagama Group consists of interfingering sandstone and mudrock forming centimetric beds, which show parallel lamination and normal sorting. These are generally separated from adjacent volcanic rocks by faults. The entire Kewagama Group was affected by regional metamorphism characteristic of the greenschist facies (Bouchard, 1979, 1981; Imreh, 1984; Tourigny, 1984).

The Rivière Dufresnoy Formation (nAdy) is the oldest unit; it outcrops on the eastern shore of Dufresnoy Lake and SE of Dufresnoy River (sheet 32D07). The Rivière Dufresnoy Formation sedimentary units consist of alternating grey lithic wacke (70%) and dark-grey to black mudrock (30%). The sequence also contains polygenetic conglomerate passages, observed, among others, in drilling in the Bouchard-Hébert Mine area (Goutier, 1997). Small sorted beds contain parallel lamination, suggesting turbiditic flows comparable to those of other units in the Kewagama Group. This formation locally lies on volcanics of the Blake River Group (Goutier, 1997).

Very characteristic outcrops of the Mont-Brun Formation are located on the shore of the Kinojévis River near the village of Mont-Brun (sheet 32D07). Typically, light grey sandstone and dark grey mudrock form millimetre to centimetre-thick beds created by turbidity currents. Contacts with adjacent volcanic units are commonly marked by faults. The Mont-Brun Formation extends from the Porcupine-Destor Fault in the Rouyn-Noranda region (sheet 32D11) to the south of the Camflo Mine, east of Malartic (sheet 32D01). In the Malartic region, this formation consists mainly of sandstone beds 15 cm thick on average, pelite beds approximately 5 cm thick, beds of conglomeratic sandstone no more than 20 cm thick and iron formations a few metres wide. Most sandstone beds are sorted. In addition, sandstone beds have beige alteration colour, while those in pelites are rather brownish.

The Caste Formation consists of turbiditic sandstone and mudrock located between the Aiguebelle and La Pause faults (sheets 32D07, 32D08 and 32C05). These rocks are similar to other turbidites observed in the Kewagama Group, with the exception of finer, more siliceous and black argillaceous beds. Some beds look like black chert.


Thickness and Distribution

Rocks of the Kewagama Group mainly outcrop in sheets 32D01, 32D06, 32D07, 32D08, 32C04 and 32C05. This group extends approximately 130 km from Duparquet Lake in the west to Senneville Lake in the east.



Feng and Kerrich (1991) dated the Caste Formation to <2691 Ma and Davis (1991, 1992) dated the Mont-Brun Formation between <2682 and 2687 Ma. These ages indicate that all turbiditic sedimentary rocks in the Malartic, Cadillac and Rouyn-Noranda regions are collectively of the same age and, moreover, younger than adjacent volcanics.


Stratigraphic Relationship(s)

All the formations in the Kewagama Group are commonly bordered by faults along their contact with neighbouring volcanic units. In his studies of rocks of the Cadillac-Malartic region, Bouchard (1979, 1980) showed that sedimentary units of the Kewagama and Cadillac groups did not form a homoclinal sequence as originally proposed by Gunning and Ambrose (1940). On the contrary, they represent lithological assemblages bordered by major faults. Each of these sedimentary formations exhibits a distinctive deformation style and special interference patterns linked to polyphase tectonics, which are not found in adjacent volcanic units (Bouchard, 1981; Tourigny, 1984). 


Does not apply.


Author(s)TitleYear of PublicationHyperlink (EXAMINE or Other)
BOUCHARD, M.Tectonique de la région de Cadillac-Malartic. Ministère de l’Énergie et des Ressources, Québec; DPV 683, 16 pages.


DPV 683
BOUCHARD, M.Région de Cadillac-Malartic. Ministère de l’Énergie et des Ressources, Québec; DPV 791, 12 pages.1981DPV 791
DAVIS, D. W.Age constraints on deposition and provenance of Archean sediments in the Southern Abitibi and Pontiac Subprovinces from U-Pb Analyses of detrital zircons. Association géologique du Canada – Association minéralogique du Canada; congrès annuel conjoint avec la Society of Economic Geologists, Toronto, programme et résumés, volume 16, page A29.1991
DAVIS, D. W.Age constraints on deposition and provenance of Archean sediments in the Southern Abitibi and Pontiac Subprovinces from U-Pb analyses of detrital zircons. Lithoprobe; projet Abitibi-Grenville, rapport d’atelier, Montréal 1991, pages 147-150.1992
DIMROTH, E. – BOIVIN, P. – GOULET, N. – LAROUCHE, M.Tectonic and volcanological studies in the Rouyn-Noranda area. Ministère des Richesses naturelles, Québec; DP 138, 59 pages.1973DP 138
DIMROTH, E. – ROCHELEAU, M.Volcanology and sedimentology of Rouyn-Noranda area, Québec. Association géologique du Canada – Association minéralogique du Canada; livret-guide d’excursion A-1, Université Laval, Québec.1979
DIMROTH, E. – IMREH, L. – ROCHELEAU, M. – GOULET, N.Evolution of the south-central part of the Archean Abitibi Belt, Quebec. Part 1: Stratigraphy and paleogeographical model. Canadian Journal of Earth Sciences; volume 19, pages 1729-1758.1982Source
FENG, R. – KERRICH, R.Single zircon age constraints on the tectonic juxtaposition of the Archean Abitibi greenstone belt and Pontiac Subprovince. Geochimica et Cosmochimica Acta; volume 55, pages 3437-3441.1981Source
GOUTIER, J.Géologie de la région de Destor (32D/07-200-0201). Ministère des Ressources naturelles, Québec; RG 96-13, 39 pages.1997RG 96-13
GUNNING, H.C. – AMBROSE, J.W.Malartic area, Abitibi County, Quebec. Geological Survey of Canada; Paper 37-4.1937Source
GUNNING, H.C. – AMBROSE, J.W.The Timiskaming-Keewatin problem in the Rouyn-Harricanaw region, north-western Quebec. Transactions of the Royal Society of Canada; volume 33, pages 19-49.1939
GUNNING, H.C. – AMBROSE, J.W.Malartic area, Quebec. Geological Survey of Canada; Memoir 222, 142 pages.1940Source
IMREH, L.Sillon de La Motte-Vassan et son avant-pays méridional : synthèse volcanologique, lithostratigraphique et gîtologique. Ministère de l’Énergie et des Ressources du Québec; MM 82-04, 72 pages.
1984MM 82-04
IMREH, L.Notes accompagnant les cartes préliminaires au 1:15 840 de l’Abitibi-Est méridional – projet de gitologie prévisionnelle – coupure 32D/01. Ministère de l’Énergie et des Ressources du Québec; MB 90-371991MB 90-37
LATULIPPE, M.Excursion géologique / geological excursion,
Val-d’Or – Malartic. Ministère des Richesses naturelles; DP 367, 129 pages.
1976DP 367
PILOTE, P. – McNICOLL, V. – DAIGNEAULT, R. – MOORHEAD, J.Géologie et nouvelles corrélations dans la partie ouest du Groupe de Malartic et dans le Groupe de Kinojévis, Québec. Ministère de l’Énergie et des Ressources naturelles, Québec; MB 2009-09, pages 55-60.2009MB 2009-09
TOURIGNY, G.Géologie structurale et métamorphisme des roches précambriennes du Groupe de Kewagama dans la région de Cadillac-Malartic, Abitibi, Québec. Mémoire de maîtrise, Université de Montréal, Montréal, Québec, 98 pages.1984




13 novembre 2018