|Author:||Moukhsil and Doucet, 1999|
|Type area:||Village Lakes area (NTS sheet 32B03)|
|Geological province:||Superior Province|
|Geological subdivision:||La Grande Subprovince|
|Lithology:||Tonalite, granodiorite and monzogranite|
Table des matières
The Quindèle Pluton was defined by Moukhsil and Doucet (1999) southwest of the Village Lakes area (sheet 33B03). The work of Bandyayera and Caron-Côté (2018, 2019) shows that its extent continues for >20 km south, in the Glas Lake area (NW corner of sheet 32O14).
The Quindèle Pluton was subdivided by Moukhsil and Doucet (1999) into two informal units: nAqdl1 and nAqdl2.
Unit Aqdl1 consists of a package of tonalite and granodiorite that cannot be mapped separately at the 1:50 000 scale. In the Glas Lake area, tonalite represents >60% of the pluton. It is a medium to coarse-grained biotite tonalite, heterogranular in places, homogeneous, foliated, locally gneissic and weakly magnetic. The rock is whitish grey in altered surface and contains 10-15% biotite. It is common to observe centimetric and discontinuous horizons of hornblende granodiorite, typically coarse-grained, foliated, in diffuse contact with tonalite, suggesting magma mixing.
Granodiorite is medium to coarse grained, heterogranular, homogeneous and foliated. It is beige in altered surface and greenish grey in fresh exposure. In general, the rock is slightly magnetic. It locally contains 1 to 3% euhedral to subhedral whitish K-feldspar phenocrystals (<1 cm). It is characterized by the ubiquitous presence of hornblende (5-20%) and minor magnetite (1%). Hornblende grains are aligned and stretched parallel to foliation. Granodiorite locally contains horizons of hornblende-clinopyroxene quartz monzodiorite, medium-grained, homogeneous and foliated. Quartz monzodiorite typically contains 20% of ferromagnesian minerals (hornblende, clinopyroxene and biotite).
Unit nAqdl1 contains up to 10% decametric enclaves of paragneiss, diorite, tonalitic gneiss and, locally, amphibolite derived from basalt, whose elongation is subparallel to regional foliation.
Unit Agdl2 consists of medium-grained, locally pegmatitic, whitish monzogranite. In thin section, the rock is composed of 30% quartz, 30% microcline, 28% plagioclase and 3-5% brownish biotite. Apatite, magnetite and epidote are accessory minerals that make up ~2% of the rock.
The Quindèle Pluton forms a large intrusive mass located south of the Village Lakes area (sheets 33B03 and 33B04), and north of the Abigail and Glas lakes area (sheets 33O13 and 33O14). The pluton is 35 km long and 25 km wide.
The Quindèle Pluton intrudes into the contact zone between the Eastmain Group to the north, and the Champion Complex to the south. It contains kilometric enclaves belonging to the Middle Eastmain Gabbro and Diorite unit. the contact with the Natel Formation (Eastmain Group), or with the Middle Eastmain Gabbro and Diorite, is marked by shear zones. Rocks are highly deformed, mylonitized and folded.
Does not apply.
MOUKHSIL, A., DOUCET, P. 1999. GEOLOGIE DE LA REGION DES LACS VILLAGE. MRN. RG 99-04RG 99-04, 33 pages and 1 plan.
BANDYAYERA, D., CARON-CÔTÉ, E. 2018. Géologie de la région du lac des Montagnes, sous-provinces de La Grande, de Nemiscau et d’Opatica, Eeyou Istchee Baie-James, Québec, Canada. MERN. CG-2018-03CG-2018-03, 1 plan.
BANDYAYERA, D., CARON-CÔTÉ, E. 2019. Géologie de la région du lac des Montagnes, sous-provinces de La Grande, de Nemiscau et d’Opatica, Eeyou Istchee Baie-James, Québec, Canada. MERN. BG 2019-03.