|Author:||Charette and Beaudette, 2018|
|Geological province:||Churchill Province|
|Geological subdivision:||Ungava Orogen / Narsajuaq Arc|
|Lithology:||Potassic intrusive igneous rock|
Table des matières
The Kuugaq Suite was introduced by Charette and Beaudette (2018) to distinguish well-foliated, even-grained and partially recrystallized granite lithologies from late, weakly foliated to massive potassic intrusions of the Narsajuaq Arc. The unit’s name is taken from the Kuugaq River located on NTS sheet 35L01.
Granite is fine to medium grained, even grained and locally granoblastic. It is characterized by a well-developed foliation or banded appearance, and a small proportion of mafic minerals. It contains 2-5% diorite or quartz diorite enclaves. Hematitization is usually observed and results in either a characteristic pinkish colour or a pinkish diffuse banding. K-feldspar proportion varies from 25 to 40% and is concentrated mainly in millimetric to centimetric, discontinuous bands in diffuse contact in the granite matrix. These bands typically account for 15 to 20% of the lithology. Foliation is marked by biotite, which forms thin millimetric horizons and makes up between 5 and 15% of the rock. Accessory minerals observed in thin section are hornblende, zircon, apatite, sphene and, locally, chlorite.
Unit pPkug1 forms kilometric zones scattered throughout the Narsajuaq Arc. These zones are elongated following the east-west regional foliation and are locally folded.
The Kuugaq Suite granite is cut by granitoid intrusions and plutons of the Sanningajualuk Suite (pPsnn) and locally occurs as enclaves within them. It is generally close to large masses of foliated charnockite of the Siurartuuq Suite (pPsir1). However, the contact between these two units was not observed in the field. The contact is sharp with mesocratic hypersthene gabbronorite and diorite of the Pingasualuit Complex (pPpgs1).
Does not apply.