Geology

REGIONAL GEOLOGY


The Laird Lake property comprises part of the Red Lake Greenstone belt (RLGB), which lies within the Uchi domain of the North Caribou Terrane (Fig. 2). The RLGB is situated along the northern boundary of the Uchi domain with the NCT of the Superior Province and preserves a ~300 m.y. record of volcanism, sedimentation, plutonism, deformation, and gold mineralization ranging from Meso- to Neoarchean in age. Nine supracrustal assemblages are present within the belt and have been subdivided based on rock type, U-Pb geochronology, and geochemistry. All assemblages within the RLGB have undergone metamorphism, ranging from lower greenschist facies to upper amphibolite facies. D1 deformation in the RLGB is characterized by north-trending, south plunging F1 folds and S1/L1 fabrics. D2 deformation is characterized by east- to northeast-trending structures that are associated with the Uchian phase of the Kenoran orogeny. Gold mineralization within the Uchi domain is most often related to D2 structures. 

Figure 2: (A) Map of western Superior Province showing the sub-provinces and location of Red Lake; (B) Geological map of the Red Lake Greenstone Belt and location of the Laird Lake property. Modified from Gélinas et al. (2016) after Sandborn-Barrier et al. (2004).

PROPERTY GEOLOGY

 

An MSc thesis completed by B. Gélinas in 2016 used a combination of detailed field mapping and geochemistry to prove that both Balmer and Confederation Assemblage rocks exist at Laird Lake, which until then, had not been fully recognized. Importantly, this conclusion implies that the Laird Lake property has been dextrally offset ~9km by the Laird Lake fault from the RLGB to the east, placing the Balmer and Confederation rocks very close to the Madsen mine pre-faulting. This interpretation is further supported by regional magnetic data, which clearly shows a large structure offsetting the magnetic RLGB rocks at Laird Lake from the rest of the magnetic RLGB to the east (Fig. 3).

 

The Balmer assemblage on the Laird Lake property crops out between the Killala–Baird batholith to the north and the Confederation assemblage to the south and mainly consists of mafic volcanic rocks with lesser occurrences of ultramafic volcanic rocks, which are rarely exposed. Two chemical sedimentary horizons have been mapped on the property and occur as 1.5 m thick chert–magnetite BIF with magnetite-rich layers hosting variable amounts of hematite and pyrite. The Confederation assemblage at Laird Lake is roughly 1 km wide to the east, thinning to less than 100 m towards the west and lies between the Balmer assemblage and the undated Medicine Stone pluton. The assemblage is mainly composed of thick mafic volcanic flows, separated by equally thick intermediate to felsic volcanic rocks, and zones of interlayered mafic to felsic volcanic packages.

Figure 3: Regional magnetic map highlighting the ~9 km offset between the Laird Lake property and the Starrat-Olsen and Madsen Mines.

MINERALIZATION

 

Most known gold occurrences at Laird Lake occur along the Balmer-Confederation contact for up to ~6 km in strike length (Fig. 4) and correlate to deformation zones characterized by intense shearing, folding, and intense alteration; of particular importance is the presence of silicification, iron-oxide, and disseminated sulfides (Figs. 5 and 6). These zones may also contain discrete smoky quartz veins that contain visible gold accompanied by blebby sulfides that have recently returned extremely high gold grades up to 373 g/t Au (Fig. 6; see press release from Dec 2024).

Figure 4: (A) Map showing the distribution of known gold occurrences at Laird Lake and location of the Lee Lake Shear Zone (B); (C) Image of the Austin Horizon from the Madsen mine.
Figure 5: Outcrop photographs from Laird Lake showing local high-strain zones characterized by strong deformation, iron-oxide alteration, silicification, and disseminated sulfides.
Figure 6: (A) Hand sample photograph showing visible gold in a smoky quartz vein that returned 373 g/t Au; (B) Hand sample photograph showing altered Balmer mafic volcanic rock characterized by strong iron-oxide alteration and disseminated sulfides that returned 3.89 g/t Au (B).

Prospecting work over recent years has also uncovered significant gold mineralization within the Confederation Assemblage rocks south of the Balmer-Confederation contact, such as the SHGX trench, which returned channel sample results of 5.29 g/t Au over 2.25m and 2.13 g/t Au over 6.67m (Fig. 7).

Figure 7: Overhead drone image of the SHGX trench overlain by an image of interpreted folding with colours representing gold grades.

Detailed mapping of the trench combined with high resolution drone imagery shows a clear relationship between high-grade mineralization and folding, which has important implications for future exploration work on the property. Importantly, Gelinas (2016) noted the presence of mineralized, chaotically folded metasomatic banding at the Lee Lake Shear Zone, which is nearly identical to the rocks comprising the Austin Horizon at the Madsen mine (Fig. 4). This is a fundamental observation that supports the interpretation that the same rocks hosting gold mineralization at the Madsen Mine are also hosting gold mineralization at Laird Lake.