Summary:
The Nalunaq deposit lies within the Psammite Zone in southern Greenland that hosts the Nanortalik Gold Belt. This zone is part of the Ketilidian Mobile Belt which evolved between 1850 Ma and 1725 Ma during interpreted northward subduction of an oceanic plate under the southern margin of the Archean North Atlantic Craton.
The geology of the Nalunaq Mountain is dominated by a package of fine- to medium-grained tholeiitic basalt flows and locally coarser, sub-concordant doleritic sills. This package is part of the Nanortalik Nappe and has been thrust over metasediments. The sequence is intruded by later granites and several generations of late aplite and pegmatite dykes.
Due to the lack of primary volcanic textures and a lack of age relations of the rock sequence, the true stratigraphic way up is unknown. The stratigraphy has therefore been assigned into the Structural Footwall (“FW”) and Structural Hangingwall (“HW”) with respect to the main gold-mineralised quartz vein.
There is a less continuous and thinner auriferous quartz vein about 15–20 m above the MV known as the Hangingwall Vein (“HWV”). Additionally, exploration work carried out by Amaroq since 2022 has identified an auriferous quartz vein envelope situated approximately 75 m above MV (the “75 Vein”).
Structural Footwall
Volcanic and volcaniclastic rocks comprise a sequence of silicified siltstone with abundant sulphides and intercalated graphitic beds, fine-grained amphibolite and coarse-grained dolerite sills or dykes which can be several metres thick, all intruded by thin aplite dykes or sills. Greenish calc-silicate alteration appears to be more common in the FW than the HW, present as elongated lenses and stringers that become increasingly parallel to the MV the closer they become to it. Whilst most authors refer to this alteration as calc-silicate, it more correctly comprises garnetepidote and clinopyroxene alteration. The sequence of sulphide-rich volcanics represent part of the lowermost stratigraphy of the Nanortalik Nappe and are the base of the mineralised thrust sheet.
Nalunaq Main Vein
The main mineralised horizon is represented by the 0.5–2.0 m thick MV, commonly with increased alteration extending for up to 1.0–1.5 m in width on both sides of the vein. The MV slightly crosscuts the foliation and can be traced at surface for over 1 km on the east- and north-facing slopes of Nalunaq Mountain, about 250 m across the western face of the mountain, and at least 800 m down the southwestern slopes.
Hangingwall Vein
The HWV, situated approximately 15–20 m above the MV, is less continuous, thinner (typically only up to 10 cm thickness) and lower grade than the MV. It pinches out along strike and may only be represented by thin seams of calc-silicate alteration and silicification in the volcanic rocks, or it is not present at all. It is possible that it represents a splay off the MV. Amaroq has not observed this structure underground but noted its presence above the MV on the west face of the mountain. Amaroq considers that the HWV may provide additional opportunities for exploration.
75 Vein
A mineralised quartz vein structure known as “75 Vein” (due to its approximate relative position 75 m above the MV) with comparable characteristics to MV was identified in 2022 and is being assessed as part of ongoing exploratory activities. The vein was identified via the use of drone imagery (clarifying its relative position), re-sampling of historical drillholes, recent drill campaigns, and geological modelling which has demonstrated its potential for continuity. 75 Vein is considered a priority exploration target.
Structural Hangingwall
The HW consists of a sequence of fine-grained amphibolite and medium- to coarse-grained dolerites, with the MV often carrying increased gold grades at the contact with these dolerites.
Mineralisation
Gold occurs in structures both within the supracrustal rocks of the Psammite Zone as well as in the Julianehåb Batholith. The gold is typically associated with arsenic-bismuth-tungsten-copper-(molybdenum). Arsenic is found in small but widespread amounts in the region and is considered a good proxy for gold mineralisation. Mineralisation at Nalunaq, in common with other lode-gold style systems are generally characterised by a high nugget effect (>50%) and the presence of coarse gold particles (>100 µm in size).
Kaltoft et al. report that the principal mineralised body at Nalunaq, the Main Vein, and associated zones of veining are hosted within a “continuous ductile shear zone” that is related to deformation and metamorphism associated with the regional Nanortalik Nappe structure, emplaced in a brittle-ductile regime during multiple influxes of hypothermal fluids (300–600°C).
Kaltoft et al. suggest that mineralisation is related to the late-stage deformation events of the Ketilidian Orogeny and were contemporaneous with granite emplacement.
The Main Vein structure varies in width from 0.05 m to 2.00 m, maintains an average dip of 38° towards the southeast, and contains high and sometimes bonanza gold grades (up to 3,777.0 g/t Au over 0.8 m in NQ154, from 92.44 m to 93.24 m). Exposures of the vein in underground development often display pinch and swell structures, show evidence of both compressive and dilatational postmineralisation deformation, and are cut by late aplitic dykes.
The vein also often displays perpendicular quartz-filled tension gashes . These may be developed either upwards from the Main Vein or, more rarely, downwards. Their presence alludes to deformation in a brittle environment, rather than ductile as suggested by previous workers.
Gold occurs mostly in the native form and locally as the gold-bismuth alloy maldonite and is associated with native bismuth. Gold fineness ranges from about 800 to 950. Lollingite and arsenopyrite are also observed. Native gold particles range in size from a few microns up to 8 mm, with coarse visible gold being common in the high-grade sections of the Main Vein.
Vein Complexities
As well as complications caused by offsets on late faults, there are also complexities within the vein itself.
Whilst the basic structure that hosts the Main Vein shows continuity over thousands of metres, the vein is more variable and shows marked pinching, swelling and splitting, sometimes reducing from tens of centimetres in width to a few centimetres or pinching-out completely over a few metres. Where the vein pinches out, the hosting structure can still be identified, often with hydrothermal alteration and some minor, poorly mineralised veinlets. In some areas, the Main Vein is cut or invaded by aplite dykes.
Deposit Types
The gold mineralisation at Nalunaq is hosted within an amphibolite-granite sequence and presents characteristics of a narrow-vein orogenic “lode-gold” system.
Key characteristics of this system include:
• Vein thickness: Mineralised veins are typically less than 1 m in true thickness, which is consistent with the narrow-vein orogenic gold system model;
• Quartz veining: The system remains predominantly characterised by quartz veining, which forms the host for gold mineralisation;
• Structural control: Gold mineralisation is strongly influenced by structural features such as shear zones, faulting, and deformation, which control the distribution of veins and gold;
• Hydrothermal alteration: Both the hangingwall and footwall exhibit symmetrical hydrothermal alteration, indicative of fluid movement and interaction with the surrounding rocks;
• Gold distribution: The gold is present as coarse, often visible grains, which contribute to a nuggety grade distribution, typical of orogenic gold deposits;
• Formation conditions: Formation occurred at temperatures between 300°C and 600°C at a depth of approximately 10 km, associated with brittle-ductile deformation typical of the region.
Commodity Production
Gold production results for 2024 are reported from November 27, 2024, the date of the first gold pour, after a 10-hour processing period.
| Commodity | Units | 2025 | 2024 |
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Gold
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koz
| ....  | .... |
All production numbers are expressed as metal in doré.
^ Guidance / Forecast.