Following two summers of mapping in the Cadieux and Campan lake areas, Hocq (1985) grouped two isolated plutons of granite and leucogranite within the “Rivière des Antons Granitoid Massifs”. These two plutons, a few kilometres apart, are hosted in gneiss (Hocq, 1985). Following mapping work in the Léran Lake (NTS sheets 23D11, 23D12, 23D13, 23D14 and 23D15; Talla Takam and Beauchamp, 2016) and Emmanuel Lake (NTS sheets 33A09, 33A10, 33A15 and 33A16; Massei and Hammouche, 2016) areas, these two intrusions are integrated within a larger unit referred to as the Des Antons Granite (nAant). This unit is mainly composed of granite injections and extends along a predominantly E-W orientation. It locally contains metric to kilometric enclaves of Laguiche Complex metasedimentary rocks. Other isolated intrusions a few hundred metres wide with the same geochemical signature also belong to this unit. However, some of these intrusions have a tonalitic composition and have been assigned to unit nAant2.

Building on the mapping work of Talla Takam and Beauchamp (2016) and Massei and Hammouche (2016), Chartier-Montreuil et al. (in preparation) redefine this unit as the Des Antons Suite. Following a geological mapping campaign at 1:50 000 scale, Chartier-Montreuil and Saint-Laurent (2024) identified the presence of Des Antons Suite granites in the northern part of the Caulincourt Lake area (sheet 33A06), and suggested that the granites identified by Beauchamp (2020) in the NW quadrant of the Cadieux Lake area (sheet 33A07) also belonged to this suite.

The name “Des Antons” refers to the eponymous river located near the area where the “’Rivière Des Antons Granitoid Massifs”’ were initially identified by Hocq (1985).

Rocks that form the Des Antons Suite (nAant) are mainly granitic, but locally show granodioritic, quartz monzonitic or quartz syenitic composition. These compositional variations are caused by the polyphase character of this unit. This feature is clearly visible on the magnetic gradient map of the region, which allows for identifying changes in the magnetite content of the various intrusive phases. However, the different phases are difficult to detect at the outcrop scale. This type of assemblage is interpreted as an intrusion complex (Morfin, 2014).

On the geological map, the Des Antons Suite can take several forms: 1) a large continuous masses; 2) smaller kilometric intrusions that can be considered as small plutons, and 3) dykes. In all cases, granite is injected subparallel to the main foliation and is ubiquitous in all outcrops of the Laguiche Complex metasedimentary rocks, locally enclaving these rocks in proportions that can exceed 90%.

In general, unit nAant1 rocks are leucocratic, beige to pinkish white or pale green. Their grain size varies from medium to coarse. Heterogeneous pegmatitic textures are also common and vary at the outcrop scale.

The rocks are generally massive, but may be slightly foliated. Some also show rotational structures of quartz and feldspar grains in a finer matrix, suggesting deformation of the rock at low temperature (Passchier and Trouw, 2005). Within the granite, biotite (up to 20%) is commonly observed interstitially or in stretched clusters in the foliation. Biotite or amphibole schlierens can also be observed, as well as paragneiss enclaves from the Laguiche Complex varying in shape and size. In general, the boundary between paragneiss and granite is marked by layers of biotite.

In addition to quartz, K-feldspar, plagioclase and biotite, a number of trace and accessory minerals can be found: apatite, zircon, titanite, garnet, amphibole, orthopyroxene, magnetite and other unidentified opaque minerals. Myrmekite is also present in some quartz grains. Substitute minerals are present as well, such as chlorite ± epidote as a replacement for biotite, which is replaced almost entirely in some rocks, or sericite as a replacement for plagioclase and K-feldspar.

Two ages have been obtained from a Des Antons Suite biotite-magnetite granite in the SW quadrant of sheet 33A15. The first dating used the U-Pb system on generally highly altered zircons and returned an age of 2658 ±8 Ma (Davis and Sutcliffe, 2018). The second dating used the U-Pb system on monazites and returned an average age of metamorphism of 2675 ±5 Ma (MSWD = 0.3). The disparity between these two ages is difficult to explain even considering the polyphase nature of the Des Antons Suite, particularly given that the estimated age of metamorphism is older than the age of emplacement. Zircon alteration could have an impact on the dating age.