Annuncio • May 19
Eclipse Metals Ltd Presents Results from New 3D Modelling of Airborne Magnetic Data over the Grønnedal-Ika Carbonatite-Syenite Complex At Its Ivittuut Multi-Commodity Project (MEL2007/45) in SW Greenland
Eclipse Metals Ltd. announced present results from new 3D modelling of airborne magnetic data over the Grønnedal-Ika carbonatite-syenite complex at its Ivittuut multi-commodity project (MEL2007/45) in SW Greenland. The Grønnedal-Ika complex is one of the larger intrusions of the Gardar Province, a suite of alkaline igneous rocks emplaced into a continental rift system in South Greenland in Mesoproterozoic times. The igneous complex at Grønnedal-Ika measures approximately 8km by 3km in exposed dimension and consists primarily of layered nepheline syenites that were intruded by a porphyritic syenite and a plug of carbonatite. The carbonatite consists of varying amounts of calcite, siderite and magnetite. Towards the centre of the carbonatite plug, the amount of siderite increases. Large amounts of magnetite occur where later mafic dykes cut the siderite-rich part of the carbonatite. Magnetite is exclusively secondary after original siderite as a result of decarbonation and oxidation (i.e., contact metamorphism) in the vicinity of the mafic dykes (e.g., Halama et al., 2005). The Grønnedal-Ika complex is recognised by the Geological Survey of Denmark and Greenland (GEUS) as one of Greenland's prime REE targets (Paulick et al., 2015). The Company recently contracted Fathom Geophysics Australia Pty Ltd. (Fathom Geophysics) to complete 3D inversion modelling of magnetic data relating to a semi-regional (200m-line spaced), heliborne DIGHEM survey conducted in 1995, with survey parameters and data re-processing described previously. This 3D unconstrained inversion of the magnetic data was undertaken to estimate the subsurface distribution of magnetite in the bedrock and gain a better understanding of the potential depth extent and geometry of the magnetic bodies. The modelling used the industry standard 3D UBC inversion code, a numerical algorithm developed by the University of British Columbia, which models the geophysical data into a potential rock volume that may be responsible for the observed magnetic measurements at surface. The algorithm works to minimise the difference between the observed data (i.e., the data measured by the survey) and the calculated data (i.e., the forward response of the 3D earth model) such that the model presents a valid solution based on the data collected. In the case of the Grønnedal-Ika complex, the igneous rocks mapped at surface correlate with distinct magnetic anomalies identified in the modelling. In particular, the magnetic anomalies correlate with magnetite-bearing carbonatite, carbonatite breccia and younger olivine dolerite as mapped by previous explorers. The strongest magnetic anomalism, observed in the southern central Grønnedal-Ika complex, coincides with areas where grab samples of magnetite-bearing carbonatite and carbonatite breccia, collected by the Company in 2021, returned total REE (TREE) content of up to 34,468 ppm (c.3.45% TREE). Key findings of the 3D inversion modelling included: Grønnedal-Ika complex comprises at least 2 large and vertically extensive magnetic bodies that range in size from 1,200m × 600m to 2,700m × 1,000m and extend to >900m below surface. Peak RTP amplitude of the strongest magnetic response is 6,000 nT (nanotesla). The bodies have apparent pipe-like geometries. The northern body plunges moderately to steeply towards the south whilst the southern body is near-vertical. The northern and southern bodies appear to coalesce into a single body beyond 700m depth. Comparing the size of the magnetic response with the extend of the mapped carbonatite suggests there is a larger potential extent of magnetite-bearing carbonatite and carbonatite breccia in the subsurface than indicated by earlier mapping. Fathom Geophysics also completed a cursory review of the EM data acquired as part of the 1995 DIGHEM survey. This review included digitisation of probable EM bedrock conductors recorded by the survey contractor at the time of data delivery. EM bedrock conductors cluster within the area of the strongest magnetic anomalism in the central portion of the Grønnedal-Ika complex. Two additional clusters of EM bedrock conductors are evident outside the Grønnedal-Ika complex and are recommended for field checking. Discussion of results Eclipse's 3D modelling of airborne magnetic data over the Grønnedal-Ika complex, one of Greenland's prime REE targets, provided new insights into the subsurface distribution of magnetic bedrock and possible architecture of this composite and structurally dismembered intrusive complex. Modelling revealed several vertically extensive magnetic bodies in the central portion of the Grønnedal- Ika complex that are up to 1,200m-long, 600m-wide, extend to >900m below surface and have a peak anomaly amplitude of 6000 nT. These pipe-like magnetic bodies are spatially coincident with historic ground magnetic anomalies (up to 20,000 nT) (Bondam, 1992) and probable EM bedrock conductors identified by a previous explorer. Reconnaissance exploration by Eclipse Metals in 2021 found a strong correlation between REE mineralisation (up to c. 3.45% TREE), contained in magnetite-rich carbonatite and carbonatite breccia and domains of most intense magnetic anomalism. Magnetic anomalism at Grønnedal-Ika is known to be caused by magnetite-bearing carbonatite, which was explored in the mid-1900s for its magnetite iron and niobium potential but not for REE. Drilling was limited to six angled diamond bore holes for a total downhole length of 750m (Bondam, 1992). As described by Halama et al. (2005), large amounts of magnetite occur where later mafic dykes cut the siderite-rich part of the carbonatite in the centre of the Grønnedal-Ika complex. This magnetite is exclusively secondary in origin and replaced primary siderite as a result of decarbonation and oxidation (i.e., contact metamorphism) in the vicinity of a series of mafic dykes that cut the Grønnedal-Ika complex. It is likely that these secondary processes acted to scavenge and concentrate REE into the secondary magnetite. The magnetite is also mapped in the EM data with probable bedrock EM conductors clustering in the central part of the Grønnedal-Ika complex where the Company has sampled magnetite-rich carbonatite. Importantly, comparing the size of the magnetic response with the extend of the mapped carbonatite suggests there is a larger potential extent of carbonatite than indicated by the earlier mapping. Latest findings provide Eclipse Metals with a new REE targeting model and clear targets for follow-up exploration. Next steps envisaged by the Company include: Field reconnaissance of and grab sampling in areas of magnetic and EM anomalism. Detailed geological mapping and the relogging of historic drill core. Data integration and interpretation. Generation and testing of drill targets.