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Valiquette Pluton
Stratigraphic label: [narc]vaq
Map symbol: nAvaq

First published: 31 May 2018
Last modified:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Translation of original French

 

 

Informal subdivision(s)
Numbering does not necessarily reflect the stratigraphic position.
None
 
Author:Bandyayera and Daoudene, 2018
Age:Neoarchean
Reference section: 
Type area:Champion Lake area (NTS sheet 32N09)
Geological province:Superior Province
Geological subdivision:La Grande Subprovince
Lithology:Granitic intrusive rocks
Type:Lithodemic
Rank:Lithodeme
Status:Formal
Use:Active

 

 

Background

The Valiquette Pluton is a lithodeme (Bandyayera and Daoudene, 2018) describing a large intrusive mass located north of Valiquette Lake, which occupies the northern half of the Champion Lake region (sheet 32N09), where large, representative outcrops are located.. It was a former member of the Champion Complex, assigned by Card and Ciesielski (1986) to the La Grande Subprovince. The Rivière Rupert Shear Zone marks the contact between the Valiquette Pluton and the Nemiscau Subprovince (Bandyayera and Daoudene, 2018).

Description

The unit consists of locally pegmatitic, medium to coarse-grained biotite granite. It is homogeneous, massive to very weakly foliated. The rock, which is locally hematitized, is typically pink to pale pink in fresh exposure and altered surface. It generally contains 1-5% biotite, 2% hornblende and 2% magnetite. Biotite is partially chloritized and locally epidotitized. It shows in places biotite schlierens (concentrated in more magnetic levels) that are likely the result of the assimilation of supracrustal rocks. The Valiquette Pluton contains metric enclaves of gneissic tonalite, amphibolite, diorite and porphyritic granodiorite. 

From a geochemical perspective, biotite granite is type I, peraluminous, calc-alkaline to shoshonitic, potassium-rich (K2O >4 wt.%) and characterized by negative europium (Eu) anomalies. A dozen lithogeochemical analyses show that the granite is syncollisional (Pearce et al., 1984). 

Thickness and distribution

The Valiquette Pluton extends from east to west over a length of more than 50 km and a width of 15 km. The magnetic susceptibility of the rock is low and homogeneous, which allows its extent to be clearly defined on geophysical maps (D’Amours, 2011).

Dating

None.

Stratigraphic Relationship(s)

The Valiquette Pluton cuts the tonalitic gneiss, tonalite and granodiorite units of the Champion Complex. At its southern limit, the Valiquette Pluton cuts volcanic mafic rocks of the Lac des Montagnes Group of the Nemiscau Subprovince. This contact is also evidenced by the presence of shear zones of the Nemiscau and Rupert rivers. The Valiquette Pluton also contains amphibolitized, weakly migmatitized volcano-sedimentary rock enclaves, which were assigned to the Anatacau-Pivert Formation further north and described by Moukhsil (2000). 

Paleontology

Does not apply.

References

Author(s)TitleYear of PublicationHyperlink (EXAMINE or Other)
BANDYAYERA, D. DAOUDENE, Y.Géologie de la région du lac Champion, sous-provinces de La Grande et de Nemiscau, à l’est de Waskaganish, Municipalité d’Eeyou Istchee Baie-James, Québec, Canada. Ministère de l’Énergie et des Ressources naturelles, Québec.2018Bulletin géologiQUE
CARD, K. D. – CIESIELSKI, A.DNAG N°1 Subdivisions of the Superior Province of the Canadian Shield. Geosciences Canada; volume 13, pages 5-13.1986Source
D’AMOURS, I.Synthèse des levés magnétiques de la Baie-James. Ministère des Ressources naturelles et de la Faune, Québec; DP 2011-08, 5 pages, 2 plans.2011DP 2011-08
MOUKHSIL, A.Géologie de la région des lacs Pivert, Anatacau, Kauputauchechun et Wapamisk (SNRC 33C/01, 33C/02, 33C/07 et 33C/08). Ministère de l’Énergie et des Ressources naturelles, Québec; RG 2000-04, 49 pages, 4 plans.2000RG 2000-04
PEARCE, T. H. – HARRIS, B.W. – TINDLE, A. G.Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. Journal of Geology; volume 25, pages 956-983.1984Source

 

8 novembre 2018