|Author:||Moukhsil and Côté, 2017|
|Reference section:||Charnockite outcrop (16-GC-1049)|
|Type area:||NTS sheet 31P11|
|Lithology:||Charnockite, granitic gneiss, enderbite, granite, quartz monzodiorite, jotunite|
Table des matières
The Vermillon Plutonic Suite was defined by Moukhsil and Côté (2017) in the Wemotaci area, Haut-Saint-Maurice.
The Vermillon Plutonic Suite describes a group of intrusive rocks recognized in the river area of the same name. Analyzed samples yielded 60 to 76.2% SiO2 contents. Rocks are metaluminous (Maniar and Piccoli, 1989), type I (igneous origin, Chappell and White, 1974), and suggest emplacement in a volcanic arc environment (Pearce et al., 1984).
Charnockite (hypersthene granite) is a highly deformed, medium-grained rock that contains up to 5% gabbronorite boudins <5 cm thick and approximately 5% pegmatite intrusions. It is composed of quartz in large zones with undulatory extinction, perthite, uncommonly antiperthite, magnetite, hornblende and pyroxenes. Orthopyroxene is rimmed by clinopyroxene, which gives charnockite a coronitic texture. Zircon, garnet, titanite and apatite are accessory minerals. Locally, development of myrmekites is observed at the expense of plagioclase.
Greenish enderbite (hypersthene tonalite) is medium grained with granoblastic texture locally gneissic. It includes red garnet and magnetite. Leucocratic granite, greyish or whitish, is homogeneous, foliated, medium to coarse grained and contains biotite and some amphibole. Quartz in large zones is associated with plagioclase showing polysynthetic twins and K-feldspar more or less perthitic. K-feldspar-biotite-hornblende granite is medium grained and more or less pinkish. Medium-grained granitic gneiss contains biotite, green hornblende and magnetite. Locally perthitic K-feldspar has tartan twinning. Gneiss is cut by millimetric to centimetric pegmatite veins.
The Vermillon Plutonic Suite is present southwest of the Wemotaci region (sheet 31P11) and extends westward.
The Vermillon Plutonic Suite is intruded by kilometric dykes of the Roc Suite and by rocks belonging to the Toad and Pieds Mouillés intrusive suites. It also contains kilometric klippes of the Wabash Complex.
Does not apply.