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Anville Pluton
Stratigraphic label: [narc]anv
Map symbol: nAanv

First published: 26 April 2019
Last modified:

 

 

 

 

 

 

  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.
 
nAanv1 Granodiorite
 
Author(s): Midra et al., 1992
Age: Neoarchean
Stratotype: None
Type area: The Anville Pluton outcrops well along forest roads east and south of Anville Lake (NE part of NTS sheet 32G11)
Geological province: Superior Province
Geological subdivision: Abitibi Subprovince
Lithology: Tonalite, granodiorite
Category: Lithodemic
Rank: Lithodeme
Status: Formal
Use: Active

 

Related unit(s)

 

 

Background

Intrusive rocks of the Anville Pluton were originally mapped by Remick (1956, 1957) and Lyall (1959). They are included in the Lapparent Intrusive Suite, first named by Racicot et al. (1984). The Anville Pluton is described in the report of Midra et al. (1992).

 

 

Description

Anville Pluton, Undivided (nAanv): Tonalite and Tonalite Containing Basalt and Gabbro Enclaves

According to Midra et al. (1992, p. 29): “The pluton consists generally of medium-grained grey tonalite, except in the western part, where its composition gradually changes to light pink porphyritic granodiorite.”

Tonalite is subhedral and displays a cataclastic to mylonitic texture in the southern part of the pluton.

According to the same author: “The main minerals encountered are: plagioclase, quartz, biotite, hornblende and microcline. Accessory minerals are epidote, allanite, sphene, chlorite, apatite, muscovite and opaque minerals. Plagioclase (An25-28) forms euhedral to subhedral millimetric crystals. It is locally zoned and, in some cases, has myrmeckitic edges. The core of plagioclase is commonly altered to epidote and sericite. Quartz (0.05-1.5 mm) is interstitial to plagioclase and has undulatory extinction. In a few thin sections, grains have sutured edges. Tabular biotite (0.1-3.5 mm) highlights foliation of the rock. It is locally altered to chlorite or muscovite, and is commonly associated with sphene and epidote. Subhedral hornblende (0.1-3 mm) is restricted to a few samples. It is commonly surrounded by biotite. Microcline is in a minor phase in tonalite […].”

 

 

Anville Pluton 1 (nAanv1): Granodiorite

Granodiorite is composed of quartz (25%), albite or oligoclase (40-45%), K-feldspar (10-15%), green hornblende (10%), white mica (3-4%), epidote (4-5%) and accessory minerals such as ilmenite, apatite and zircon (Picard, 1985).

According to Midra et al. (1992, p. 29): “Foliation in granodiorite is marked by quartz stretching, the alignment of microcline phenocrystals and micaceous minerals. This foliation is locally accompanied by a slight subhorizontal mineralogical lineation. In places, quartz grains display crenulation at the outcrop scale.”

 

Thickness and distribution

The pluton has an ovoid shape with a long axis ~28.5 km parallel to regional foliation WNW-ESE. The short axis, oriented NNE-SSW, has a maximum length of 9.2 km.

 

Dating

A sample taken on outcrop 2012-YD-2676 yielded a crystallization age of 2714.8 ±0.6 Ma (Augland et al., 2016).

 

Unit Sample Number Isotopic System Mineral Crystallization Age (Ma) (+) (-) Inherited Age (Ma) (+) (-) Reference(s)
nAanv 2012-YD-2676A U-Pb Zircon 2714.8 0.6 0.6 2720 3 3 Augland et al., 2016

Stratigraphic Relationship(s)

The Anville Pluton cuts mafic volcanic rocks of the Chrissie and Obatogamau formations, intrusive rocks of the Lapparent Intrusive Suite (Houghton Pluton, gneissic units, Est Tonalite), and the Fardoche Stock.

Paleontology

Does not apply.

References

Publications available through SIGÉOM Examine

AUGLAND, L.E., DAVID, J., PILOTE, P., LECLERC, F., GOUTIER, J., HAMMOUCHE, H., LAFRANCE, I., TALLA TAKAM, F., DESCHENES, P.-L., GUEMACHE, M.A., 2016. Datations U-Pb dans les provinces de Churchill et du Supérieur effectuées au GEOTOP en 2012-2013. MERN, GEOTOP; RP 2015-01, 43 pages.

LYALL, H B., 1959. REGION DE BRONGNIART – LESCURE, DISTRICT ELECTORAL D’ABITIBI-EST. MRN; RG 085, 45 pages, 1 plan.

MIDRA, R., CHOWN, E H., TAIT, L., 1992. GEOLOGIE DE LA REGION DU LAC DICKSON (BANDE CAOPATINA-DESMARAISVILLE). MRN; MB 91-30, 65 pages.

 

 

Other publications

 

 

BÉDARD, P.L. 1992. Géochimie et pétrographie du pluton archéen de Houghton en Abitibi nord. Université du Québec à Chicoutimi; Doctoral thesis, 309 pages. https://constellation.uqac.ca/1446

GERVAIS, D. 1986. Le caractère de la zone de contact entre l’intrusion tonalitique syn- à postcinématique d’Anville et le terrain de gneiss du Massif de Lapparent. Université du Québec à Chicoutimi; Bachelor’s thesis, 56 pages.

 

Suggested Citation

Ministère de l’Énergie et des Ressources naturelles (MERN). Anville Pluton. Quebec Stratigraphic Lexicon. http://gq.mines.gouv.qc.ca/lexique-stratigraphique/province-du-superieur/pluton-anville_en [accessed on Day Month Year].

 

Contributors

First publication

Patrice Roy, P. Geo., M.Sc. patrice.roy@mern.gouv.qc.ca (redaction)

Mehdi A. Guemache, P. Geo., Ph.D. (coordination); François Leclerc, P. Geo., Ph.D. (critical review);  Mélina Langevin, B.Sc. and Simon Auclair, P. Geo., M.Sc. (editing); Céline Dupuis, P. Geo., Ph.D. (English version); Ricardo Escobar Moran (HTML editing).

 

 

 

18 août 2021