Rocher-Quénonisca Intrusive Suite
Stratigraphic label: [narc]rok
Map symbol: nArok

First published: 15 September 2017
Last modified:



Translation of original French



Informal subdivision(s)
Numbering does not necessarily reflect the stratigraphic position.
nArok Peridotite
Author: Franconi, 1974
Age: Precambrian / Archean / Neoarchean
Reference section:  
Type area: The Rocher-Quénonisca Intrusive Suite includes the Whitefish Intrusion (nAwf) which outcrops mainly between the Quénonisca and Rocher lakes (NTS sheets 32K09 and 32K10), the Rocher Intrusion (nAlrc) and another small peridotite intrusion of less than 1.5 km in diameter, which cuts paragneiss of the Rocher Complex (nAroc) and migmatitic gneiss of the Bétulaie Complex (nAbtu) in the Rocher Lake area (NTS sheet 32K09).
Geological province: Superior Province
Geological subdivision: Opatica Subprovince
Lithology: Ultramafic to intermediate rocks
Unit type: Lithodemic
Rank: Suite
Status: Formal
Use: Active






This unit was originally described as the « Rocher-Kenonisca Massif » by Franconi (1974) in his report on the mapping of the western part of the Frotet-Evans volcano-sedimentary band. It has been renamed « Rocher-Quénonisca Intrusive Suite » by Brisson et al. (1998) during mapping of the Rocher Lake area (NTS sheet 32K09). Adding the Whitefish Intrusion (nAwf) and the Rocher Intrusion (nAlrc) as lithodemes in the Rocher-Quénonisca Intrusive Suite is proposed as a result of Leclerc and Caron-Côté (2017) field work and compilation.



The Rocher-Quénonisca Intrusive Suite consists of two formal lithodemes: 1) the Whitefish Intrusion (nAwf), characterized by purple gabbros and monzonites, and 2) the Rocher Intrusion, composed of peridotite, plagioclase peridotite, pyroxenite and purple gabbro. The suite also includes a peridotite intrusion (nArok) with a diameter of less than 1.5 km that has been recognized in drillholes (Rhéaume, 1999; Turcotte and Tuchscherer, 2013). 


Thickness and distribution

The Whitefish Intrusion forms an NE-SW oriented band just over 25 km long by 1.5 to 5 km wide which cuts tonalities of the Salamandre Intrusive Suite and volcano-sedimentary rocks of the Rocher Complex. The suite also includes the Rocher Intrusion and a small peridotite intrusion less than 1.5 km in diameter. These two intrusions, clearly visible on aeromagnetic maps, are located on the edge of the Nipukatasi Massif (NTS sheet 32K09). 


Analysis of a sample of massive, homogeneous and granophyric bird’s eye gabbro coming from a drill hole made in the Rocher Intrusion gave a crystallization age (TIMS, U-Pb on zircons) of 2703 +7/-4 My (Bandyayera and Sharma, 2006). 

Isotopic System Mineral Cristallization Age (My) (+) (-) Reference(s)
U-Pb Zircon 2703 7 4 Bandyayera and Sharma, 2001

Stratigraphic Relationship(s)

The Rocher-Quénonisca Intrusive Suite comprises ultramafic to mafic and intermediate rocks that cut both tonalities of the Salamandre Intrusive Suite and metavolcanic rocks of the Rocher Complex, the latter locally occurring as xenoliths in the gabbro. The Rocher-Quénonisca Intrusive Suite is therefore considered late-tectonic by Bandyayera and Sharma (2001). 


Does not apply.



Author(s) Title Year of Publication Hyperlink (EXAMINE or Other)
BANDYAYERA, D. – SHARMA, K.N.M. Minéralisations en Ni-Cu±ÉGP dans la bande volcano-sédimentaire de Frotet-Evans (SNRC 32K). Ministère des Ressources naturelles, Québec; MB 2001-06, 74 pages. 2001 MB 2001-06
BRISSON, H. – GOSSELIN, C. – FALLARA, F. – GAULIN, R. – DION, D.-J. Géologie de la région du lac Rocher. Ministère des Ressources naturelles, Québec; RG 98-05, 22 pages. 1998 RG 98-06
FRANCONI, A. Géologie de la moitié ouest de la bande volcano-sédimentaire de Frotet-Evans, territoire d’Abitibi, rapport intérimaire. Ministère des Richesses naturelles, Québec; DP 265, 141 pages. 1974 DP 265
LECLERC, F. – CARON-CÔTÉ, E. Levé géologique dans la Sous-province d’Opatica au nord-est de Matagami (Région du lac Amisquioumisca). Ministère de l’Énergie et des Ressources naturelles, Québec. 2017 Bulletin géologiQUE
RHÉAUME, P. International Kirkland Minerals Inc. & Bushman Resources ltd. Joint Venture Huskies Property Report on the 1999 Exploration Program Townships 1116 & 1216, Québec NTS 32K/09. Ministère de l’Énergie et des Ressources naturelles, Québec; GM 56803, 45 pages. 1999 GM 56803
TURCOTTE, A.P. – TUCHSCHERER, M.G. Assessment report on the 2013 winter exploration program James Bay Project. Ministère de l’Énergie et des Ressources naturelles, Québec; GM 67560, 132 pages. 2013 GM 67560





27 février 2018