The nature and genesis of magmatic Ni-Cusulfide mineralisation in and around the Stendalen Intrusion, south Greenland

Project Highlights:

• First study of newly discovered magmatic Ni-Cu sulfide mineralisation in south Greenland
• Opportunity to work with Amaroq Minerals on an exciting field exploration program
• Be part of a research group at the forefront of global Ni research

Overview:

Magmatic Ni-Cu-PGE sulfide deposits are the world’s largest source of Ni and PGE and significant sources of associated Cu and Co, and are thus essential for modern and future technologies in the drive to decarbonise the energy sector (e.g. in electric vehicles batteries). Whilst many deposits are found along craton margins and have a plume-related origin, there are an increasingly recognised class of these deposits that formed in orogenic belts, particularly in the past 2 billion years. Such belts include the Central Asian Orogenic Belt in China (home to deposits like Huangshandong), the Caledonian orogenic belt (home to mineralisation the focus of revived exploration activities in recent years in NE Scotland and Norway), and the 1.8-1.9 Ga Kotalahti and Vammala belts in Finland. Stendalen is situated on a major trans-lithospheric fault on the margin of the Nain craton that links the Gardar Igneous Province with the major Ni-Cu deposit at Voisey’s Bay. At ~1.3Ga, extension along the Gardar-Voisey’s Bay fault zone, channelled fertile mantle derived material into this belt resulting in both magmatic sulphide and alkali igneous intrusions. However, field relationships suggest Stendalen to be older (as much as 1.8Ga) implying that Stendalen is more likely associated with the earlier Ketilidian orogen, which was also influenced by the Gardar-Voisey’s Bay fault zone. The Stendalen intrusion is a roughly circular gabbroic complex located at the junction of the Lindenow and Nørrearm fjords. The intrusion comprises an upper pyroxene-rich homogenous gabbro unit and an undrelying pyroxene-olivine-poor layered gabbro sequence, separated by a 510m thick magnetite-ilmenite-rich layer which was the original Ti-V resource target. The gabbro intrudes through a sequence of metasediments (migmatites) which are locally sulphide and graphite bearing. The intrusion has been folded in two events, creating a bowl-like basal contact to the metasediments. Newly-discovered sulphide mineralisation is mostly disseminated throughout the gabbroic intrusion and consists primarily pyrrhotite-pentlandite-chalcopyrite. Towards the base of the intrusion a distinctive blebby texture within “taxite” is found, with fluid interactions through magma mixing as the presumed cause (see Figure 1). This texture is associated with some of the world’s largest nickel deposits, including Noril’sk, Sudbury and Voisey’s Bay. 

Key research questions: This project aims to answer the following key research questions:

1) What is the geodynamic setting of the Stendalen Intrusion and how does it fit into the regional Ketalidian orogenic belt?

2) What is the nature of the sulfide mineralisation in terms of metal tenors, mineralogy, Ni-Cu-PGEAu contents?

3) What are they key controls on the formation of the Stendalen Ni-Cu sulfide mineralisation?

Methodology:

The geodynamic setting will be investigated using a combination of field mapping, which will include fieldwork in Greenland on the Stendalen Intrusion and the surrounding region (including other mafic intrusions) to give context. Geochemical fingerprinting will aim to determine source signatures indicative of geodynamic setting, alongside concurrent geochronological data that is being completed separately. In addition, comparison with other intrusions will inbvestigate any key fertility indicators. The nature of the sulfide mineralisation will be examined using state of the art mineralogical techniques at the University of Leicester, including Automated Quantitative Mineralogy using ZEISS’ Mineralogic software, alongside in situ Laser Ablation-ICP-MS of sulfides and associated minerals and traditional bulk rock geochemical methods. The controls on the genesis of sulfide mineralisation will involve S and C-O isotope analysis to determine the role of contamination from host rocks containing sulfide, sulphate, carbonate and/or graphite. This work will be undertaken at the NERC Isotope Facility (SUERC) at East Kilbride. Possible timeline: Year 1: Work on drillcores from 2024 summer field season. Mineralogical work to classify the sulfide mineralisation styles. Geochemical analysis and characterisation of the Stendalen Intrusion. Field season in Greenland in summer 2025 to samples regional mafic intrusions. Year 2: Field season in Greenland in summer 2026 for any follow up sampling to address questions from the first two years. Regional mapping and sampling of Stendalen and other magmatic intrusions in the region to build up a magmatic framework for the region with follow up geochemical characterisation (possibility to focus on comparative intrusions in the area). Presentation at international conference. Year 3: Isotope work on sulfide mineralisation. Final mineralogical and geochemical work on samples from Presentation at international conference. Start of thesis write up.

Full project please see https://target.le.ac.uk/wp-content/uploads/2024/04/Leicester_HOLWELL.pdf

For further information and reading on this project please contact David Holwell direct at david.holwell@le.ac.uk

To apply please refer to https://le.ac.uk/study/research-degrees/funded-opportunities/target-studentship