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Baudan Suite
Stratigraphic label: [narc]ban
Map symbol: nAban

First published: 19 April 2018
Last modified:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Translation of original French

 

 

Informal subdivision(s)
Numbering does not necessarily reflect the stratigraphic position.
 
nAban1 Porphyroclastic monzogranite
nAban1a Porphyroclastic farsundite
 
Author:Verpaelst et al., 2000
Age:Neoarchean
Reference section: 
Type area:Koroc River area (NTS sheet 24I)
Geological province:Churchill Province
Geological subdivision:Core Zone
Lithology:Porphyroclastic monzogranite
Type:Lithodemic
Rank:Suite
Status:Formal
Use:Active

 

 

Background

The term Baudan Complex was first used by Verpaelst et al. (2000) to define a unit of granitic gneiss and granitic intrusions. This unit name was not subsequently used by Simard et al. (2013), Lafrance et al. (2014, 2015, 2016) and Charette et al. (2016), who preferred to distinguish regional gneiss zones from late intrusions. The grey gneiss of tonalitic to granitic composition were then assigned to the Ungava Complex. However, in the synthesis of the southeastern Churchill Subprovince (SECP), different lithotectonic blocks were identified and it appears that the gneiss observed east of the Moonbase Shear Zone (MSZ) are distinct from those identified in the Kuujjuaq and Ungava Bay area west of the Rivière George Shear Zone (RGSZ). The Kangiqsualujjuaq Complex has been redefined to consolidate all of the grey, tonalitic to granitic gneiss located between the MSZ in the west and the Blumath Deformation Corridor (BDC) in the east. The Kangiqsualujjuaq Complex thus includes some of the outcrops previously assigned to the Baudan Complex, those of grey granitic gneiss, but excludes the later intrusive rocks, which were assigned to the Qarliik Suite (Mathieu et al., 2018) and the porphyroclastic monzogranite outcrops, which now represent the Baudan Suite as defined by Mathieu et al. (2018).

Description

The Baudan Suite comprises only one unit of porphyroclastic monzogranite (nAban1) associated with positive aeromagnetic anomalies. 

Baudan Suite 1 (nAban1): Porphyroclastic Monzogranite

Unit nAban1 is predominantly composed of monzogranite but also has a small proportion of quartz monzonite and syenogranite. Monzogranite is strongly foliated (and/or lineated) and locally takes on the appearance of an augen gneiss. The rock is coarse grained, medium pink, black and white speckled, but the minerals form fine-grained recrystallized monomineralic clusters, particularly on the grain edges. It is magnetic and characterized by the presence of 25 to 55% pink microcline porphyroclasts 0.5 to 3 cm long, most often recrystallized and lenticular in shape. Quartz tends to align in thin discontinuous bands or lenses. It shows a strong undulatory extinction and its edges are commonly indented. Mafic minerals (15%) form lenticular clusters and laminaes that mould felsic mineral clusters. Hornblende and biotite occur in similar proportions. Microcline is often perthitic and rimmed with myrmekites. Accessory minerals are numerous and commonly coarse grained. The main ones are allanite, epidote, magnetite, sphene, apatite, muscovite, zircon and chlorite. 

Baudan Suite 1a (nAban1a): Porphyroclastic Farsundite

Locally, porphyroclastic monzogranite contains orthopyroxene and has been assigned to subunit nAban1a. The structural and mineralogical characteristics are similar to those of unit nAban1 with the exception of the presence of hypersthene and lower proportions of biotite. Hypersthene is variable uralitized (hornblende rim) and serpentinized. The rock also takes on a green or brown sugar colour characteristic of orthopyroxene rocks.

Thickness and Distribution

The Baudan Suite covers an area of approximately 500 km2 in the Koroc River area. It forms intrusions that are several kilometres wide, followed over several kilometres and oriented along a general NW-SE axis.

Dating

An Archean age of approximately 2623 Ma was obtained from a sample described as a gneissic porphyritic monzogranite in the Koroc River area (Verpaelst et al., 2000). 

Isotopic SystemMineralCrystallization Age (Ma)(+)(-)Reference(s)
U-PbZircon2622.58.28.2David et al., 2009

Stratigraphic Relationship(s)

The Baudan Suite is part of the ancient rocks of the Core Zone. Relationships with other Archean rocks were not observed in the field. It is cut by granitic intrusions of the Qarliik Suite (pPqik).

Paleontology

Does not apply.

References

Author(s)TitleYear of PublicationHyperlink (EXAMINE or Other)
CHARETTE, B. – LAFRANCE, I. – MATHIEU, G.Géologie de la région du lac Jeannin (SNRC 24B). Ministère de l’Énergie et des Ressources naturelles, Québec.2016Rapport géologique électronique
DAVID, J. –  MAURICE, C. –  SIMARD, M.Datations isotopiques effectuées dans le nord-est de la Province du Supérieur – Travaux de 1998, 1999 et 2000. Ministère des Ressources naturelles et de la Faune, Québec; DV 2008-05.2009DV 2008-05
LAFRANCE, I. – BANDYAYERA, D. – BILODEAU, C.Géologie de la région du lac Henrietta (SNRC 24H). Ministère des Ressources naturelles, Québec; RG 2015-01, 62 pages.2015RG 2015-01
LAFRANCE, I. – BANDYAYERA, D. – CHARETTE, B. – BILODEAU, C. – DAVID. J.Géologie de la région du lac Brisson (SNRC 24A). Ministère de l’Énergie et des Ressources naturelles, Québec; RG 2015-05, 61 pages.2016RG 2015-05
LAFRANCE, I. – SIMARD, M. – BANDYAYERA, D.Géologie de la région du lac Saffray (SNRC 24G-24F). Ministère des Ressources naturelles, Québec; RG 2014-02, 49 pages.2014RG 2014-02
MATHIEU, G. – LAFRANCE, I. – VANIER, M.-A.Géologie de la région de Pointe le Droit, sud-est de la Province de Churchill, Nunavik, Québec, Canada. Ministère de l’Énergie et des Ressources naturelles, Québec.2018Bulletin géologiQUE
SIMARD, M. – LAFRANCE, I. – HAMMOUCHE, H. – LEGOUIX, C.Géologie de la région de Kuujjuaq et de la baie d’Ungava (SNRC 24J et 24K). Ministère des Ressources naturelles, Québec; RG 2013-04, 60 pages.2013RG 2013-04
VERPAELST, P. – BRISEBOIS, D. – PERREAULT, S. – SHARMA, K.N.M. – DAVID, J.Géologie de la région de la rivière Koroc et d’une partie de la région de Hébron (24I et 14L). Ministère des Ressources naturelles, Québec; RG 99-08, 62 pages, 10 plans.2000RG 99-08

 

12 novembre 2018