Licence 2020/31, “Saarloq”, covers an area of 818 km2 and is predominantly underlain by granitoid rocks of the Julianehåb Batholith, with several enclaves of metavolcanic and appinitic rocks. The principal feature of interest is the large, crustal-scale Saarloq Shear Zone that runs through the licence in a north-easterly direction. The shear zone and its subsidiary features represent prospective settings for structurally controlled gold mineralisation, especially in areas where brittle deformation has occurred.
Qaqortoq is the closest major town to the Saarloq licence area and forms a good staging post for exploration work. The western half of the licence covers a multitude of islands and the mainland is incised by long fjords. Access to many western parts of the licence is possible by boat and on foot via the fjords which are usually ice-free all year. The eastern half of the licence can be accessed by helicopter. The licence is located approximately 50 km NW of AEX’s Nalunaq gold project.
Geology and Mineralisation
The licence is predominantly underlain by granites and granodiorites belonging to the Julianehåb Batholith.
The oldest rocks are gneisses which are mainly granodioritic or quartz dioritic with biotite and hornblende and are located in the southwest and north-easterly areas of the license. These units are enclosed within an early granite of the batholith. Elsewhere there are late-stage granites which are described as biotitic, biotitic foliates, biotitic-rich enclaves, hornblendic, hornblendic foliates and with amphibolitic enclaves. Throughout the licence are small areas of basic intrusives, diorites and appinitic rocks. Microsyenite and dolerite dykes of Gardar age are mapped, particularly in the western part of the licence.
Steep to vertical shear zones are an important feature of the Julianehåb Batholith in this area. Descriptions of them are given by Chadwick et. al., (1994) and Chadwick and Garde (1996). They have widths of a few centimetres up to more than one kilometre and trend towards the northeast, parallel to the schistosity of the granitoid rocks.
The principal structure of interest here is the Saarloq Shear Zone which runs through the licence area in a north-easterly direction. This is the largest shear in the region (Chadwick et. al., 1994) and occupies a 1.5 km wide zone. It can be traced for at least 50 km along strike and appears to link with intensely deformed rocks in the Saarloq area at the southwest end of the shear (Windley, 1966). Deformation along the Saarloq Shear Zone appears to have been intense. Mineral textures indicate crystal-plastic solid-state deformation, and mineral lineations suggest transcurrent displacement probably relating to the subduction event in the area. Deformation has led to the formation of mylonites and ultramylonites derived from the granitic rocks adjacent to the shear zone. Partial melting may have been a result of localised shear heating. Within about 100 m of the shear zone the regional schistosity of the granites becomes more intense. The displacement along shear zones in this area is not known, but it was probably many kilometres in the case of the Saarloq Shear Zone, as suggested by its width and the intensity of the mylonitisation. Some shear zones may have been reactivated as brittle faults in the Gardar period.
The licence area has only been explored previously at a reconnaissance level and there are not yet any published gold occurrences. However, elevated gold grades are noted in historical rock sampling data published by GEUS (Geological Survey of Denmark and Greenland) and a geochemical sampling programme by a former licence owner, Rare Earth Minerals PLC, resulted in some anomalies that should be investigated further.
The next phase of exploration will include a detailed structural assessment of the licence area, as the Saarloq Shear Zone and subordinate shear zones are likely to be the major controlling features of any gold mineralisation.
It will be particularly important to identify areas of brittle deformation as these will allow greater fluid flow and may increase the potential for mineralisation. AEX intends to conduct a programme of remote sensing analysis, prospecting and sampling and geophysical surveying over the next two years. Diamond drilling will be considered if suitable targets are defined.
1 A Competent Person’s Report on the Assets of AEX Gold, South Greenland; SRK Exploration Services Ltd., 2020