The Tasiataq Belt is located in the Tasiataq Lake area (sheets 24L12 and 24L13), where it is named. Although they did not define the unit at scale 1:1 000 000, Stevenson et al. (1969) nevertheless observed that the predominantly granitic rocks in the Tasiataq Lake area contained many basic inclusions. In the same area, Percival and Card (1994) then mapped at scale 1:500 000 a folded strip corresponding to the Tasiataq Belt. However, they defined it as a strip of metagabbroic rocks consisting mainly of fine to medium-grained hornblende-plagioclase amphibolite. On their unpublished map, Leclair et al. (2003) informally included volcanic rocks from the Tasiataq Lake area in the Tasiataq complex, while Simard (2003) used the term “Tasiataq Belt”. Since these rocks are mainly concentrated in a single belt, Simard et al. (2008) retained the unit at the lithodeme level and formally named it the Tasiataq Belt.

The Tasiataq Belt consists of foliated and metamorphosed basalt and andesite, which are interstratified with layers of felsic volcanic rock and iron formation. The belt also includes some ultramafic rock layers that are locally associated with mesocratic gabbro (Simard et al., 2008; Simard, 2008). Simard (2003) separated layers of mafic (nAtsq1), felsic (nAtsq2) and ultramafic (nAtsq3) volcanic rocks into three distinct informal units. Descriptions of these units are taken from the geological map of Simard (2003).

Unit nAtsq1 is the main unit of the Tasiataq Belt. It is composed of undifferentiated mafic volcanic rocks of basaltic and andesitic composition. The rock is dark green to rust brown, foliated and fine to medium grained. Mafic volcanics are interstratified with layers of felsic volcanic rocks and silicate facies iron formations.

Tasiataq Belt 2 (nAtsq2) : Felsic Volcanic Rocks

Unit nAtsq2 consists of undifferentiated felsic volcanic rock layers, including rhyolite, dacite and associated volcaniclastic rock (block tuff). The rock is grey to rust brown, foliated to mylonitic and fine to medium grained. Felsic volcanics are also interstratified with silicate facies iron formations.

Tasiataq Belt 3 (nAtsq3) : Ultramafic Rocks

Layers of undivided pyroxenite, peridotite, hornblendite and serpentinite are observed locally. The rock is dark green to dark brown, fine to coarse grained and shows carbonate alteration. Unit nAtsq3 locally contains mesocratic gabbro.

Thickness and distribution

The Tasiataq Belt forms a main strip ~1 km thick. It extends for a distance of ~30 km and turns at an angle of about 90° to two thirds of its length. It is located north of Feuilles River, near Tasiataq Lake (sheets 24L12 and 24L13).

Dating

A U-Pb age of 2740 ±4 Ma was obtained in a felsic volcanic rock (David et al., 2009). Zircons from this sample are heterogeneous, with several having older cores inherited from the Douglas Harbour Domain basement (David et al., 2009).