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Amarault Pluton
Stratigraphic label: [ppro]ama
Map symbol: pPama
 

First published: 5 December 2017
Last modified: 7 October 2022

 

 

 

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(s): Lafrance et al., 2016
Age: Paleoproterozoic
Stratotype: None
Type area: Brisson Lake area (NTS sheet 24A)
Geological province: Churchill Province
Geological subdivision: Falcoz Lithotectonic Domain
Lithology: Quartz diorite
Category: Lithodemic
Rank: Lithodeme
Status: Formal
Use: Active

Background

The Amarault Pluton was introduced by Lafrance et al. (2016) in the Brisson Lake area (NTS 24A) to describe a small quartz diorite pluton located in the SE part of the Falcoz Lithotectoninc Domain (Lafrance et al., 2018).

 

Description

On outcrops, quartz diorite of the Amarault Pluton is very homogeneous. In altered surface, it is characterized by a typical black and white mottled appearance caused by the arrangement of grains that form clusters of ferromagnesian and quartzofeldspathic minerals. Some intrusions of granular enderbite are observed, as well as rare decimetric to metric paragneiss enclaves. Quartz diorite contains 8-15% quartz, up to 7% K-feldspar and 20-30% ferromagnesian minerals consisting of green hornblende and brown biotite in roughly equal proportions. Relics of orthopyroxene variably transformed into iddingsite as well as clinopyroxene in the core of hornblende crystals were also observed in several places. The rock is massive in appearance, but may contain slight foliation defined by the alignment of ferromagnesian minerals. In thin sections, quartz diorite displays well-preserved magmatic textures and low recrystallization indicated by the presence of plagioclase subgrain clusters. There are also myrmekitic textures associated with small interstitial K-feldspar grains. Apatite, opaque minerals and zircon are present in minor amounts.

 

Thickness and distribution

The Amarault Pluton is associated with an elliptical magnetic trough approximately 13 km long and 5 km wide. It covers a small area (~51 km2) in the SE part of the Falcoz Lithotectonic Domain (Lafrance and Vanier, 2022). The magnetic signature of the Amarault Pluton is similar to that of paragneiss of the Lake Harbour Suite (pPhb1b). It is indeed surrounded by a paragneiss layer a few hundred meters wide.

Dating

None.

Stratigraphic Relationship(s)

The Amarault Pluton is cut by medium-grained granitic enderbite intrusions of the Inuluttalik Suite and contains orthogneiss and paragneiss enclaves of the Sukaliuk Complex and Lake Harbour Suite respectively.

Paleontology

Does not apply.

References

Publications Available Through SIGÉOM Examine

LAFRANCE, I., BANDYAYERA, D., CHARETTE, B., BILODEAU, C., DAVID, J., 2016. GÉOLOGIE DE LA RÉGION DU LAC BRISSON (SNRC 24A). MERN; RG 2015-05, 64 pages, 1 plan.

LAFRANCE, I., CHARETTE, B., VANIER, M.-A., 2018. Sud-est de la Province de Churchill, Nunavik, Québec, Canada : synthèse de la géologie. MERN; BG 2018-12

LAFRANCE, I., VANIER, M.-A., 2022. Domaine lithotectonique de Falcoz, sud-est de la Province de Churchill, Nunavik, Québec, Canada : synthèse de la géologie. MERN; BG 2022-01, 2 plans.

 

Suggested Citation

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

Contributors

First publication

Isabelle Lafrance, P.Geo., M.Sc. isabelle.lafrance@mern.gouv.qc.ca (redaction)

Mehdi A. Guemache, P.Geo., Ph.D. (coordination); Claude Dion, Eng., M.Sc. (critical review and editing); Céline Dupuis, P.Geo., Ph.D. (English version); Caroline Thorn (HTML editing). 

Revision(s)

Isabelle Lafrance, P.Geo., M.Sc. (redaction)

Céline Dupuis, P.Geo., Ph.D. (coordination); Marc-Antoine Vanier, Eng., M.Sc. (critical review); Simon Auclair, P.Geo., M.Sc. (editing); Dominique Richard, GIT, Ph.D. (English version); André Tremblay (HTML editing).

 
7 février 2024