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Tower Plutonic Suite
Stratigraphic label: [mpro]tow
Map symbol: mPtow

First published: 20 October 2017
Last modified:

 

 

 

 

 

 

 

 

 

 

 

 

 

Translation of original French

 

 

 

 

 

Informal subdivision(s)
Numbering does not necessarily reflect the stratigraphic position.
 
None
 
Author: Moukhsil and Côté, 2017
Age: Mesoproterozoic
Reference section: Charnockite outcrop (16-LC-4076A)
Type area: NTS sheet 31P12
Geological province: Grenville Province
Geological subdivision: Allochton
Lithology: Charnockite, mangerite, granite, quartz monzodiorite, jotunite
Type: Lithodemic
Rank: Suite
Status: Formal
Use: Active

 

 

Related unit(s)

None

 

 

 

 

Background

The Tower Plutonic Suite was defined during the work of Moukhsil and Côté (2017) in the Wemotaci area, Haut-Saint-Maurice.

 

 

Description

The Tower Plutonic Suite forms an intrusion of felsic to intermediate rocks with or without orthopyroxene that outcrops primarily in sheet 31P12. From a geochemical perspective, these rocks have contents of 68 to 75% SiO2, they are metaluminous (Maniar and Piccoli, 1989) and plot in the field of Type I granites (igneous origin, Chappel and White, 1974). Analyzed samples plot in the fields of volcanic arc granites and intraplate granites.

 

Charnockite, usually of syenogranitic composition, is coarse grained and locally porphyritic. It is composed of large quartz zones, perthitic K-feldspar phenocrystals (<2 cm long), plagioclase, orthopyroxene, biotite and traces of garnet. Accessory minerals are zircon and magnetite.

The mangerite (orthopyroxene monzonite) is also porphyritic, greenish in fresh exposure and whitish in altered surface. The main minerals are quartz, feldspars, orthopyroxene, biotite, hornblende and trace clinopyroxene.

Monzodiorite and quartz monzodiorite are whitish to greyish in fresh exposure, medium grained and foliated. These rocks are magnetic and contain biotite, feldspars and some millimetric to centimetric garnet porphyroblasts.

Lastly, jotunite (orthopyroxene monzodiorite) resembles the monzodioritic facies, but is magnetic and contains more ferromagnesian minerals such as orthopyroxene, clinopyroxene and biotite.

 

 

Thickness and Distribution

The Tower Plutonic Suite forms an irregular intrusion approximately 18 km by 25 km located in sheet 31P12.

 

Dating

None. 

Stratigraphic Relationship(s)

The Tower Plutonic Suite intrudes into the Pope Plutonic Suite and Lacoste Magmatic Suite. It contains klippes of the Wabash Complex.

Paleontology

Does not apply.

References

Author(s) Title Year of Publication Hyperlink (EXAMINE or Other)

MOUKHSIL, A. – CÔTÉ, G.

Géologie de région de Wemotaci, Haut-Saint-Maurice (Partie ouest du Grenville). Ministère de l’Énergie et des Ressouces naturelles, Québec; RG 2017-03, 44 pages, 2 maps. 2017 RG 2017-03

 

 

 

 

15 février 2019