Overview and Location
The Idefix Property is located 75 kilometres northwest of the Community of Kuujjuaq, in the Nunavik region of the province of Quebec. Northern Shield currently holds a 100% interest in the Idefix Property which currently consists of 40 claims covering 18 km2. The first claims at the Idefix Property were staked in August 2011 over an area of known PGE mineralization, following on the work conducted by previous exploration companies and on regional prospecting by Northern Shield in the northern Labrador Trough in the summer of 2011. Exploration at the Idefix Property is supported by helicopter from Kuujjuaq with fishing and hunting lodges acting as site bases.
The original exploration focus at the Idefix Property was for reef-type PGE mineralization after the discovery of significant and extensive PGE mineralization in 2012 along a gabbronorite escarpment with grades up to 16 grams per tonne of platinum and palladium at a ratio of 1:3. However, during 2014 and 2015, significant advancements were made by Northern Shield in understanding the geology and geochemistry of the Idefix Property. The presence of large nickel-copper-PGE bearing sulphide globules seen in nearly every drill hole completed along the Idefix Ridge points to the possible existence of massive magmatic sulphides similar to a Noril’sk type model.
Geologically, the Idefix Property is found within the Labrador Trough, a Paleoproterozoic supracrustal sequence located at the eastern margin of the Superior Province. The sequence was folded and metamorphosed during the New Quebec Orogen, which represents the collision between the Superior Craton and the Core Zone of the Southeastern Churchill Province. The Labrador Trough is over 500 kilometres long and is composed of three cycles of sedimentation and volcanism (Clark and Wares, 2005), separated by erosional unconformities. Each cycle is further subdivided in groups and formations.
The first two cycles are intruded by numerous tholeiitic, mafic-ultramafic sills referred to as the Montagnais sills. These sills are contemporaneous and comagmatic with associated volcanic rocks. The mineralization at the Idefix Property is found in one of those mafic-ultramafic sills.
Exploration History at the Idefix Property
After a year of thorough desktop studies and research on the northern Labrador Trough, in early September 2011, Northern Shield conducted a two-day reconnaissance exploration program on the Idefix Property. Twenty-five rocks samples were collected of which 21 were from the mafic-ultramafic sill and four from the country rock. Nine of the 21 samples collected from the mafic-ultramafic sill returned assays greater than 1 g/t Pt+Pd+Au with a high of 8.8 g/t Pt+Pd+Au.
During the three phases of the 2012 exploration season, the results continued to show the Idefix Property as a target with potential to host a viable PGE deposit based on some high-grade PGE values and the continuous nature of the mineralization. The Idefix PGE mineralization at that time could be traced over 1.3 kilometres. Many of the higher-grade PGE assays were sawn channel samples taken over widths of 1 metres including 15.6, 10.5, 7.6 and 6.4 g/t Pt+Pd.
In 2013, fourteen drill-holes totalling 1,501 metres were completed at Idefix. Drilling did not intercept similar grades of PGEs as seen on surface but did prove the existence of reef type mineralization averaging 0.2-0.4 g/t PGE over 16-34 metre widths that can be traced continuously for 3.5 kilometres and intermittently for up to 7 km. Of the 1,614 samples collected at Idefix, 934 assayed greater than 0.1 g/t Pt+Pd+Au, highlighting the significant enrichment of PGE at Idefix. Drilling also revealed the presence of large sulphide globules along the entire length of the Idefix Ridge.
Additionally, in 2013, significant PGE mineralization was discovered 900 meters immediately south of the Idefix Ridge. This area called “La Colline” includes a PGE-enriched zone defined by 34 continuous sawn channel samples which average 1.4 g/t Pt+Pd+Au, 0.28% Cu and 0.1% Ni over 31.35 metres. Samples at La Colline display interstitial and net-textured sulphides. The geochemical signature of the mineralization at La Colline is commonly associated with nickel-copper massive sulphides and one of the key indicators for a Noril’sk-type deposit at Idefix.
After reviewing all accumulated information at the Idefix Property, new interpretation based in part on the presence of sulphide globules along the Idefix Ridge and net-textured sulphides at La Colline suggest, with a high degree of confidence, that the reef-type mineralization was the result of the redistribution of nickel-copper-PGE sulphides in the magma from a massive sulphide source somewhere nearby in the sill. It also implies that PGE-rich nickel-copper massive sulphides (Noril’sk-type) should now be the primary target model.
Globules are blebs of sulphide that have been transported away from a pool of massive sulphide over relatively short distances by an injecting pulse of magma during sill emplacement while the sulphides and host rock were still molten. The globules are delicate and rapidly deteriorate with distance from the source, meaning that the larger and more cohesive globules will be the closest to the massive sulphide source.
Because the Idefix Property was explored mostly for a reef-type PGE deposit, i.e., a low sulphide system, an EM geophysical survey was not considered originally. With the new interpretation suggesting the proximity of a massive sulphide body, a VTEMÔ survey was conducted during the summer of 2016.
The geophysical survey highlights a long continuous conductor along the base of the Idefix Ridge, which results from the high conductivity of the graphitic sedimentary units underlying the Idefix mafic-ultramafic sill. However, there is another very interesting anomaly located between La Colline and the southeast end of the Idefix ridge that could very well underline a massive sulphide body. Unfortunately, drilling in 2013 would have missed this conductor and so it remains unexplained to date. Concentrations of sulphide globules in large blocks of rocks that have fallen from the very steep south facing end of the ridge were observed but the possibility of more falling blocks was considered too high a risk to continue prospecting along that face. Northern Shield hopes to conduct a short drill program at Idefix to test this conductor in the near future.
Noril’sk-Type Target at Idefix
The basis of the Noril’sk model for Idefix is the presence of nickel-copper-PGE rich sulphide globules in 11 of the 14 drill holes completed at the Idefix Property. Globules are blebs of sulphide that have been transported away from a pool of massive sulphide over relatively short distances by an injecting pulse of magma during sill emplacement while the sulphides and host rock were still molten. The globules are delicate and rapidly deteriorate with distance from the source, meaning that the larger and more cohesive globules will be the closest to the massive sulphide source.
The globules at Idefix can range up to 3 centimetres in diameter and contain an average of approximately 1% nickel, 3% copper and 9 g/t palladium (n=53 on 11 globules) with globules averaging as high as 2.5% Ni, 6% copper and 27 g/t palladium as indicated by portable X-ray Spectrometer (Innov-X Systems - X-50 Portable XRF). It is important to note that the Portable XRF unit does not have the capability to detect platinum at the level present in the samples. As platinum to palladium ratios at Idefix are approximately 1:3, the platinum values should be estimated at one third of the palladium values.
Clark, T. and Wares, R.P. 2005. Lithotectonic and metallogenic synthesis of the New Québec Orogen (Larbrador Trough). Ministère des Ressources naturelles, Québec, MM 2005-01, 135 p. http://gq.mines.gouv.qc.ca/documents/examine/MM200501/MM200501.pdf
James, D.T., Nunn, G.A.G., Kamo, S. and Kwok, K. 2003. The southeastern Churchill Province revisited: U-Pb geochronology, regional correlations and the enigmatic Orma Domain. Current Research, Newfoundland Department of Mines and Energy, Geological Survey Report 03-1, p. 35-45. http://www.nr.gov.nl.ca/nr/mines/geoscience/publications/currentresearch/2003/james_nunn.pdf
Map CG SIGEOM24K available on E-Sigeom – Examine database, Ministère de l’énergie et des ressources naturelles du Québec. http://gq.mines.gouv.qc.ca/documents/examine/CG24K201101/CG24K201101PLAN.pdf