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Wahemen Suite
Stratigraphic label: [narc]wah
Map symbol: nAwah
 

First published: 26 February 2018
Last modified: 4 December 2020

 

 

  DISCLAIMER: This English version is translated from the original French. In case of any discrepancy, the French version shall prevail. 

Informal subdivision(s)
Numbering does not necessarily reflect the stratigraphic position.
 
None
 
Author: Talla Takam et al., in preparation
Age: Neoarchean
Stratotype: None
Type area: Léran Lake, Bohier Island and Cadieux Lake areas (NTS sheets 23D11, 23D12, 33A07 and 33A08)
Geological province: Superior Province
Geological subdivision: Opatica and Opinaca subprovinces
Lithology: Granite
Category: Lithodemic
Rank: Suite
Status: Formal
Use: Active

 

 

Background

The Wahemen Suite was introduced by Talla Takam et al. (in preparation) to describe undeformed intrusions of white-to-pinkish patina, medium to coarse-grained, locally pegmatitic and low in mafic minerals. These granite intrusions are located in the Léran Lake (Talla Takam et al., in preparation), Bohier Island (Beauchamp et al., 2018) and Cadieux Lake (Beauchamp, 2020) areas.

 

Description

The Wahemen Suite is massive, homogeneous, heterometric and non-magnetic. This unit has very low magnetic susceptibility on the residual total magnetic field map. It is leucocratic and very poor in ferromagnesian minerals (3%). Grain contacts are gradual and diffuse, ranging from medium to coarse-grained to pegmatitic. The Wahemen Suite contains quartz, plagioclase, K-feldspar, muscovite, moderately chloritized biotite and traces of garnet, tourmaline, chlorite, beryl and apatite. Centimeter clusters of spodumene (20 to 30%) are also present at the outcrop 18-SG-7072. Garnet is microgranular and rounded (1-5 mm). It is either evenly distributed within the granite or aligned and preferentially associated with mica. Banding is magmatic in origin and results in alternating centimetric to decametric medium-grained horizons occurring as bands rich in garnet (1-3%), muscovite and tourmaline (<3%). In many places, granite has well-developed graphic textures that show the simultaneous crystallization of quartz and alkaline feldspar. Micrographic, perthitic and poecilitic microcline textures containing muscovite were observed in thin section. Pegmatic horizons are decametre to metre thick and contain rosette clusters and rods of muscovite and biotite.  

The Wahemen Suite is a target lithology for Li, Be and Ta mineralization (Éch. S894341 mineralized zone). In Quebec, the main lithium mineralization occurences are concentrated in Abitibi and in the Eeyou Istchee James Bay region; these mineralizes zones correspond to granitic pegmatites cutting Archean host rocks. In most cases, these are peraluminous granitoids (S-type), as is the Wahemen Suite.

Thickness and Distribution

The Wahemen Suite can be found in sheets 23D11, 23D12, 33A07 and 33A08. In the Léran Lake area, the suite is located north of the Upper Eastmain Greenstone Belt (UEGB). It forms an intrusive mass measuring 65 km by 5 km. In the Bohier Island and Cadieux Lake areas, the Wahemen Suite occurs as small metric bodies that cut Mesoarchean to Neoarchean rocks of the Opatica Subprovince. These intrusions are spatially associated with the borders of geological subprovinces in the Eeyou Istchee James Bay region where they generally mask contact between these subprovinces.

Dating

The Wahemen Suite is one of the youngest Archean units in the Eeyou Istchee James Bay region. The U-Pb age on monazite obtained from a sample taken from sheet 23D12 (outcrop 16-ML-5175) indicates a crystallization age of 2640 ±10 Ma (Davis and Sutcliffe, 2018). 

Unit Sample Number Isotopic System Mineral Crystallization Age (Ma) (+) (-) Reference(s)
nAwah 2016-ML-5175A U-Pb Monazite 2640 10 10 Davis and Sutcliffe, 2018

Stratigraphic Relationship(s)

Except for diabase dykes, the Wahemen Suite is the youngest unit of the area. It cuts the regional deformation as well as all rocks with which it is in contact with (the Digne PlutonRené Group volcanic rocks, Bohier Group sedimentary rocks and the Laguiche Complex). Near contact with the UEGB, granite of the Wahemen Suite may contain up to 30% of sedimentary rock xenoliths (wacke, wacke paragneiss, metatexite and metaconglomerate) that are similar to rocks of the Bohier Group and Laguiche Complex.

Paleontology

Does not apply.

References

Publications available through SIGÉOM Examine

BEAUCHAMP, A M. 2020. Géologie de la région du lac Cadieux, sous-provinces d’Opatica et d’Opinaca, Eeyou Istchee Baie-James, Québec, Canada. MERN. BG 2019-02, 1 plan.

BEAUCHAMP, A M., MASSEI, F., DAOUDENE, Y. 2018. Géologie de la région de l’île Bohier, au contact entre les sous-provinces d’Opatica, d’Opinaca et le bassin d’Otish, au nord de Mistissini, Eeyou Istchee Baie-James, Québec, Canada. MERN. BG 2018-02, 2 plans.

DAVIS, D W., SUTCLIFFE, C N. 2018. U-Pb Geochronology of Zircon and Monazite by LA-ICPMS in samples from northern Quebec. UNIVERSITY OF TORONTO. MB 2018-18, 54 pages.

TALLA TAKAM, F., BEAUCHAMP, A.-M., MASSEI, F. In preparation. Géologie de la région des lacs Léran et Emmanuel, Québec, Canada. MERN. 

Suggested Citation

Ministère de l’Énergie et des Ressources naturelles (MERN). Wahemen Suite. Quebec Stratigraphic Lexicon. https://gq.mines.gouv.qc.ca/lexique-stratigraphique/province-du-superieur/granite-de-wahemen_en [accessed on Day Month Year].

Contributors

First publication

Anne-Marie Beauchamp, Eng., M.Sc. anne-marie.beauchamp@mern.gouv.qc.ca (redaction)

Mehdi A. Guemache, P. Geo., Ph.D. (coordination); Mélina Langevin, B.Sc. (critical review); Simon Auclair, P. Geo., M.Sc. (editing); Céline Dupuis, P. Geo., Ph.D. (English version); Nathalie Bouchard (HTML editing).  

Revision(s)

Anne-Marie Beauchamp, Eng., M.Sc. anne-marie.beauchamp@mern.gouv.qc.ca (redaction)

Mehdi A. Guemache, P. Geo., Ph.D. (coordination); Patrice Roy, P. Geo., M.Sc. (critical review); Simon Auclair, P. Geo., M.Sc. (editing); Céline Dupuis, P. Geo., Ph.D. (English version); André Tremblay (HTML editing). 

 
29 octobre 2018