Lac Doré Intrusive Suite
Stratigraphic label: [narc]cld
Map symbol: nAcld

First published: 29 March 2018
Last modified:





























Translation of original French



Informal subdivision(s)
Numbering does not necessarily reflect the stratigraphic position.
Author: Allard, 1956
Age: Neoarchean
Reference section: The official reference section was proposed by Allard for the IGC Congress (Allard, 1972) and described in the CIM excursion Guidebook (Allard, 1984). It begins in the anorthositic zone (UTM NAD83, zone 18: 564780 mE, 5515720 mN) and ends in the granophyric zone (UTM NAD83, zone 18: 564369 mE, 5513649 mN)
Type area: East of Armitage Lake (southeastern portion of sheet 32G16-200-0102)
Geological province: Superior Province
Geological subdivision: Abitibi Subprovince
Lithology: Mafic to ultramafic intrusive rocks
Type: Lithodemic
Rank: Suite
Status: Formal
Use: Active




The large Lac Doré stratiform and differentiated mafic to ultramafic intrusion was originally identified as the Lac Doré Complex (Allard, 1956; Allard, 1976). This name, which emphasized the analogy with Bushveld or Stillwater-type layered stratiform complexes, was maintained by Daigneault and Allard (1990) for historical reasons, despite the recommendations of the North American Stratigraphic Code to use the term “complex” (Articles 37d and 38; MER, 1986). The most recent version of the North American Stratigraphic Code (NASC, 2005) maintains that it is incorrect to use the term “complex” to refer to “various types of rock belonging to a single class”. For this reason, we are proposing to amend the nomenclature of the Lac Doré Complex in accordance with sections 31 to 41 of the North American Stratigraphic Code: (a) the Lac Doré Complex is renamed the Lac Doré Intrusive Suite (referred to in the rest of the text as LDIS); (b) the Lac Doré Lower Series, Lac Doré Layered Series and Lac Doré Upper Series become the Lac Doré Lower Unit, Lac Doré Layered Unit and Lac Doré Upper Unit respectively; and (c) the Layered Zone, included in the Layered Series (former nomenclature), is now referred to as the “layered zone” and is considered an informal lithodeme.



The Lac Doré Intrusive Suite (LDIS) is a stratiform synvolcanic intrusion of mafic to ultramafic composition hosted in volcanic rocks of the Obatogamau and Waconichi formations. The LDIS stratigraphy is based on the work of Allard (1967) and Allard and Caty (1969). It includes the Lac Doré Lower Unit (nAcdi), Lac Doré Layered Unit (nAcdl) and Lac Doré Upper Unit (nAcds). East of the Grenville Front Tectonic Zone, mafic to ultramafic intrusive rocks, which are deformed and metamorphosed to the amphibolite facies, were also attributed to the LDIS (Allard, 1979, 1981; Ciesielski and Madore, 1989; Bandyayera et al., 2005).


Thickness and Distribution

The Lac Doré Intrusive Suite occupies the axial section of the Chibougamau Anticline and outcrops over 5 to 7 km thick and >53 km long (Daigneault and Allard, 1990).



A quartz pyroxenite sample from the layered zone (Lac Doré Layered Unit) yielded an age of 2728.3 +1.2/-1.1 Ma and a granophyre sample from the granophyric zone (Lac Doré Upper Unit) yielded an age of 2727.0 ±1.3 Ma (Mortensen, 1993).

Isotopic System Mineral Crystallization Age (Ma) (+) (-) Reference(s)
U-Pb Zircon 2728.3 1.2 1.1 Mortensen, 1993
U-Pb Zircon 2727.0 1.3 1.3 Mortensen, 1993

Stratigraphic Relationship(s)

Rocks of the Lac Doré Intrusive Suite cut volcanic rocks of the Obatogamau and Waconichi formations at the base of the Roy Group. They are cut by diorite and tonalite of the Chibougamau Pluton.


Does not apply.


Author(s) Title Year of Publication Hyperlink (EXAMINE or Other)
ALLARD, G.O. The geology of a portion of McKenzie Township, Chibougamau District, Quebec. John Hopkins University; doctoral thesis, 168 pages. 1956
ALLARD, G.O. Géologie du quart nord-ouest du canton de Rinfret, comtés de Roberval et d’Abitibi-Est. Ministère des Richesses naturelles, Québec; RP 567, 17 pages, 1 plan. 1967 RP 567
ALLARD, G.O. Precambrian geology and mineral deposits of the Noranda – Val-d’Or and Matagami-Chibougamau greenstone belts, Quebec. Guidebook for IGC excursion A-41-C, 100 pages. 1972
ALLARD, G.O. Doré Lake Complex and its importance to Chibougamau geology and metallogeny. Ministère des Richesses naturelles, Québec; DPV 368, 487 pages, 2 plans. 1976 DPV 368
ALLARD, G.O. Prolongement du Complexe de Lac Doré dans la Province de Grenville, à l’est de Chibougamau. Ministère des Richesses naturelles, Québec; DPV 685, 21 pages, 1 plan. 1979 DPV 685
ALLARD, G.O. Quart sud-ouest du canton de Rinfret et partie du quart sud-est du canton de Lemoine : relation avec le front de Grenville. Ministère de l’Énergie et des Ressources, Québec, DPV 759, 104 pages, 1 plan. 1981 DPV 759
ALLARD, G.O. – CATY, J.-L. Géologie du quart nord-est et d’une partie du quart sud-est du canton de Lemoine, comtés d’Abitibi-Est et de Roberval. Ministère des Richesses naturelles, Québec; RP 566, 22 pages, 1 plan. 1969 RP 566
ALLARD, G.O. – CIMON, J. – GOBEIL, A. Geology and mineralization S.E. of Chibougamau. In Chibougamau: stratigraphy and mineralization – An Archean Belt with a difference. Livret-guide (Guha, J. and Gobeil, A., editors). Canadian Institute of Mining and Metallurgy, pages 123–158. 1984
BANDYAYERA, D. – CADÉRON, S. – HOULE, P. – SHARMA, K.N.M. Géologie de la région du lac Mitshisso (SNRC 32H13). Ministère des Ressources naturelles et de la Faune, Québec; RP 2005-04, 12 pages, 4 plans. 2005 RP 2005-04
CIESIELSKI, A. – MADORE, L. Litho-Tectonic Map of the Grenville Front, the Archean Parautochthonous Orthogneisses and Proterozoic Dykes in the Central Grenville Province, Southeast of Chibougamau, Quebec. Geological Survey of Canada; Open File 2059, 1 plan. 1989 Source
AIGNEAULT, R. – ALLARD, G.O. Le Complexe du lac Doré et son environnement géologique (région de Chibougamau – Sous-province de l’Abitibi). Ministère de l’Énergie et des Ressources, Québec; MM 89-03, 275 pages. 1990 MM 89-03
LECLERC, F. – ROY, P. – HOULE, P. – PILOTE, P. – BÉDARD, J.H. – HARRIS, L.B. – McNICOLL, V.J., VAN BREEMEN, O. – DAVID, J. – GOULET, N. Géologie de la région de Chibougamau. Ministère de l’Énergie et des Ressources naturelles, Québec; RG 2015-03, 97 pages, 3 plans. 2017 RG 2015-03
MINISTÈRE DE L’ÉNERGIE ET DES RESSOURCES (MER) Code stratigraphique nord-américain. Ministère de l’Énergie et des Ressources, Québec; DV 86-02, 58 pages. 1986 DV 86-02
NORTH AMERICAN STRATIGRAPHIC COMMISSION ON STRATIGRAPHIC NOMENCLATURE (NASC) North American Stratigraphic Code. American Association of Petroleum Geologists Bulletin; volume 29, pages 1547–1591. 2005 Source
MORTENSEN, J.K. U-Pb geochronology of the eastern Abitibi Subprovince. Part 1: Chibougamau – Matagami – Joutel Region. Canadian Journal of Earth Sciences; Québec; 18 pages. 1993 Source



16 janvier 2020