Fayot Suite
Stratigraphic label: [ppro]fay
Map symbol: pPfay

First published: 13 November 2017
Last modified: 1 August 2018






Translation of original French




Informal subdivision(s)
Numbering does not necessarily reflect the stratigraphic position.
Author: Lafrance et al., 2016
Age: Paleoproterozoic
Stratotype: None
Type area: Brisson Lake area (NTS sheet 24A)
Geological province: Churchill Province
Geological subdivision: George Lithotectonic Domain
Lithology: Lamprophyre
Category: Lithodemic
Rank: Suite
Status: Formal
Use: Active




The Fayot Suite was introduced in the Jeannin Lake area (Lafrance et al., 2016) to group massive lamprophyre intrusions. A detailed petrological study of the Fayot Suite was also carried out as part of an undergraduate thesis (Chartier, 2016).




The Fayot Suite consists of undeformed melanocratic (minette) and leucocratic (vogesite) lamprophyres. However, slight deformation, marked by the presence of kinks in biotite, was observed in thin sections (Chartier, 2016). These rocks are intruded by centimetric to decimetric granitic dykes that are not part of the same intrusive sequence.


Minette has a heterogeneous appearance characterized by the presence of green or black ferromagnesian mineral clusters and pink felsic clusters, millimetric to decimetric, rounded or elongated. These felsic clusters, having the same composition of vogesite, show irregular and undulating contacts and are locally dismembered (Chartier, 2016). Minette varies from very fine to coarse grained. In general, ferromagnesian minerals form millimetric to centimetric clusters, while K-feldspar (sanidine) occurs as small crystals in the matrix or as large poikilitic crystals. These are altered, rich in ferromagnesian mineral inclusions and exhibit perthitic and anti-perthitic textures. Plagioclase and quartz (<3%) are interstitial or as inclusions in ferromagnesian minerals. Vogesite forms either injections or clusters within minette, or a kilometric intrusive mass that contains minette clusters having irregular margins (Chartier, 2016). These observations could indicate an immiscibility process of magmatic fluids or late segregation.

The mineralogy of the two types of lamprophyres is similar, although the content of ferromagnesian minerals differs: 35 to 80% in minette, 5 to 35% in vogesite. On the other hand, the plagioclase content is greater in vogesite (<15%) than in minette (<1%). Ferromagnesian minerals consist of brown biotite, green hornblende, actinolite and diopside in roughly equal proportions. Green hornblende and actinolite are located on clinopyroxene grain edges, which they completely replace in places. Biotite is mostly ferriferous (lepidomelane), rich in zircon inclusions and chloritized in several places. Accessory minerals are abundant and generally coarse. These include, in order of importance, sphene, apatite, epidote, opaque minerals (magnetite and sulphides), allanite, zircon, carbonates and fluorite.

A decimetric lamprophyre dyke cutting porphyritic granodiorite of the De Pas Granitic Suite was observed near the northernmost Fayot Suite intrusion. This rock consists of a feldspar-rich fine-grained matrix that contains microphenocrystals and millimetric biotite-clinopyroxene-amphibole clusters.

Several lithogeochemical analyses, including those carried out as part of the Chartier (2016) undergraduate thesis, have highlighted the rare earth enrichment of these intrusions (≤1256 ppm total REE). Chartier’s (2016) work also indicates that this enrichment is concentrated in accessory minerals.



Thickness and Distribution

The Fayot Suite consists of five small, kilometre-wide lamprophyre intrusions hosted in the De Pas Supersuite, inside the George Lithotectonic Domain (Charette et al., 2018). 


An age around 1815 Ma, considered to be crystallization, was obtained from a minette sample collected in the summer of 2014 by the Geological Survey of Canada, in the northwestern portion of the Brisson Lake area (sheet 24H04).

Isotopic System Mineral Crystallization Age (Ma) (+) (-) Reference(s)
U-Pb Zircon 1815 3 3 Corrigan et al., 2018

Stratigraphic Relationship(s)

Despite their age similar to that of the youngest rocks of the De Pas Supersuite, those in the Fayot Suite have not been affected by regional deformation or regional metamorphism. A lamprophyre dyke assigned to the Fayot Suite cuts a porphyraceous granodiorite of the De Pas Granitic Suite. No other crosscutting relationships were observed in the field.


Does not apply.


Author(s) Title Year of Publication Hyperlink (EXAMINE or Other)
CHARETTE, B. – LAFRANCE, I. – VANIER, M.-A. George Lithotectonic Domain, Southeastern Churchill Province, Nunavik, Quebec, Canada:
Geological Synthesis. Ministère de l’Énergie et des Ressources naturelles, Québec. BG 2018-11.
2018 BG 2018-11
CHARTIER, M.O. Caractérisation pétrographique et géochimique des roches alcalines de la Suite de Fayot, Province de Churchill. Université du Québec à Chicoutimi; projet de fin d’études, 51 pages. 2016
CORRIGAN, D. – WODICKA, N. – McFARLANE, C. – LAFRANCE, I. – VAN ROOYEN, D. – BANDYAYERA, D. – BILODEAU, C. Lithotectonic framework of the Core Zone, Southeastern Churchill Province Geoscience Canada; volume 45, pages 1-24. 2018 Source
LAFRANCE, I. – BANDYAYERA, D. – CHARETTE, B. – BILODEAU, C. – DAVID, J. Géologie de la région du lac Brisson (SNRC 24A). Ministère des Ressources naturelles, Québec; RG 2015-05, 61 pages. 2016 RG 2015-05



17 août 2020