Totalling 1,889 km2, licence 2020/36 “Anoritooq” is divided into two sub-areas: a main part that lies between AEX’s Saarloq and Vagar exploration licenses and covers parts of the Niaqornaarsuk, Akuliaruseq and Nanortalik peninsulas to the northeast of Nanortalik, and a second sub-area on the south east coast of Greenland that follows the inner parts of Kangerluluk and Igutsaat Fjord. Both sub-areas can be accessed by boat or helicopter. Exploration will be supported from AEX’s camp at Nalunaq. The most advanced gold exploration target in this licence is known as Lake 410, located on the southern end of the Nanortalik Peninsula.
Geology and Mineralisation
The geology of South Greenland is dominated by the Paleoproterozoic Ketilidian orogenic belt (1850 – 1725 Ma), formed during subduction of an oceanic plate under the Archean North Atlantic Craton. The orogen can be divided into three broad zones from northwest to southeast (Figure 2):
- The Border Zone, where crystalline rocks of the Archean craton are unconformably overlain by Ketilidian supracrustal rocks
- The Julianehåb Batholith, a large polyphase calc-alkaline batholith which was emplaced in a continental arc setting, along with numerous appinite dykes
- Ketilidian supracrustal rocks that are psammitic close to the contact with the batholith and more pelitic in the southeast, with subordinate mafic volcanics and volcaniclastics, intruded by a post-orogenic suite of rapakivi granites.
The geology of the main sub-area of license 2020/36 is quite varied, comprising Julianehåb Batholith granites and granodiorites in its northern part and Ketilidian metasediments, metavolcanics and Rapakivi granites in its southern part.
The prospect that has seen most exploration is Lake 410 on the southern end of the Nanortalik Peninsula, a short distance from the town of Nanortalik. This shows several geological similarities to Nalunaq and is part of the same nappe. Crew Gold conducted several seasons of exploration here including 2,241 m of diamond drilling. This identified a mineralised structure that showed continuity over more than 700 m along strike, with intersections of up to 2.12 ppm gold over 2 m in amphibolites. AEX plans to carry out 3D modelling and further structural assessment of this target. It is not yet known if the low grades are representative of the in-situ geology or are a consequence of high nugget-effect mineralisation, similar to that found at Nalunaq, and AEX plans to collect larger samples for gold deportment studies. Prospecting will be carried out in key areas with unexplained scree sediment gold anomalies in 2020.
In addition to Lake 410, a mineralised shear zone is recorded in the northern part of the main sub-area in the Isortup Qoorua valley, to the north of AEX’s Vagar license. The shear zone is several kilometres long and historical exploration has returned chip samples up to 3.4 ppm gold that require further investigation.
The Kangerluluk sub-area is mostly underlain by granites with some enclaves of metavolcanic rocks. This area has seen little exploration although there are three published mineral occurrences. One of these occurrences at the head of Kangerluluk Fjord includes quartz veining with elevated tungsten, molybdenum and copper associated with gold, with grades of up to 1.2 % copper and 0.6 ppm gold. Lead-zinc mineralisation is also found related to later shear zones and carbonatisation. The carbonate zones contain grades of up to 2.2% lead, 4% zinc, 0.223 ppm gold and 114 ppm copper. There are also several sulphide-bearing rust zones and aplite sills that require further assessment.
On the northern side of Igutsaat Fjord, at least four distinct east-west striking rust zones are exposed in the granodiorite. Iron sulphide is disseminated in the zone and occurs in hairline fractures and veinlets with analyses showing trace amounts of gold (Stendal 1997).
A major, east-west striking, 5-8 m thick rusty aplite sill is exposed on the southern side of Igusaat Fjord. The sill strikes approximately 060° and dips 20° southeast. The aplite is enclosed in mafic sill rock, 0.5-1 m thick. Earlier mafic dykes are displaced several metres dextrally along the sill plane and the aplite appears to have been emplaced into a sub-horizontal shear zone in an earlier mafic sill. The rusty aplite contains 1-2 vol.% pyrite, both disseminated and in veinlets with grab samples returning grades of up to 1.39 ppm gold (Stendal 1997).
Enclaves of metavolcanic rock on the northern side of Kangerluluk fjord have potential to host extensions to the high-grade gold mineralisation identified on the southern side of the fjord within AEX’s Nuna Nutaaq license 2019/113, where Goldcorp reported up to 110 g/t Au over 80 cm true thickness from a NE-trending shear structure in 19972. Additional enclaves to those on the published geological maps have been identified by AEX from aerial photographs.
In addition to the published gold occurrences, gold has been reported in altered gabbros and norites of the Appinite suite from near Alluitsup Paa and on Angmalortoq Island, with samples collected by Platinova Resources in 1987 returning 440 ppb and 180 ppb respectively. AEX plan to collect samples to verify these results and assess the mineralisation style.
A priority for fieldwork in 2020 and 2021 will be to visit areas of known gold showings to understand the various types of gold mineralisation throughout the area.
A comprehensive database will be compiled, particularly for the Lake 410 target which has seen the largest amount of exploration in this licence. 3D modelling and further structural assessment will help to predict continuity of structures identified by historical drilling. Several larger samples will be taken from outcrops of mineralised features at Lake 410; for mineralogical and gold deportment studies to understand whether the mineralised structures are genuinely low grade as suggested by drilling results, or whether there is a high nugget effect that resulted in low grades in sampling data.
In addition, AEX intends to conduct a programme of remote sensing analysis, prospecting and sampling and geophysical surveying over the next two years. Diamond drilling may 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
2 Geological report on the Kangerluluk gold prospect, Southeast Greenland. GoldCorp Inc. pp. 1-57; Sannes, D.L., 1998