- The three-dimensional (3D) inversion modelling of airborne magnetic data has delineated numerous high amplitudes and vertically extensive magnetic bodies at Grønnedal-Ika.
- The magnetic bodies are up to 1,200m-long, 600m-wide and extend to >900m under the surface with a peak anomaly amplitude of 6,000 nT.
- EM bedrock conductors are agglomerated within the area with the strongest magnetic anomalism in the central section of the Grønnedal-Ika complex.
- Furthermore, two other clusters of EM bedrock conductors are located outside the Grønnedal-Ika complex and shall be field checked.
- Eclipse has applied to Mineral Resources Authority to undertake a drilling program at Grønnedal-Ika in 2022.
Shares of Eclipse Metals Limited (ASX:EPM) surged 3.85% to AU$0.027 following the announcement of outcomes of the new 3D modelling of airborne magnetic data across the Grønnedal-Ika carbonatite-syenite complex at the Ivittuut multi-commodity project (MEL2007/45).
The Grønnedal-Ika complex is among larger intrusions within the Gardar Province in South Greenland. The igneous complex at Grønnedal-Ika stretches over an 8km by 3km area, consisting primarily of layered nepheline syenites, which had been intruded by a porphyritic syenite and a carbonatite plug. The carbonatite consists of varying amounts of calcite, siderite and magnetite.
Siderite’s concentration increases towards the centre of the carbonatite plug. Also, magnetites occur in large concentrations at the location where mafic dyke cut the siderite-rich section of the carbonatite. The Geological Survey of Denmark and Greenland (GEUS) recognises the Grønnedal-Ika complex among the prime targets for REE mineralisation in Greenland.
3D modelling of magnetic data
The three-dimensional (3D) inversion modelling of airborne magnetic data has delineated numerous high amplitudes and vertically extensive magnetic bodies at Grønnedal-Ika. Eclipse is targeting REE mineralisation associated with a carbonatite syenite complex.
The magnetic bodies are up to 1,200m-long, 600m-wide and extend to >900m under the surface with a peak anomaly amplitude of 6,000 nT. These magnetic bodies are coincident with historic magnetic anomalies with a peak amplitude of 20,000 nT, and probable EM conductors delineated by a previous explorer.
Recently, Eclipse had involved Fathom Geophysics Australia Pty Ltd to undertake the 3D inversion modelling of magnetic data from the semi-regional (200m-line spaced), heliborne DIGHEM survey of 1995.
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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 the possible architecture of this composite and structurally dismembered intrusive complex.
Simplified surface geology of part the Grønnedal-Ika syenite-carbonatite complex Source: Eclipse Metals Announcement 19 May 2022
At the Grønnedal-Ika complex, igneous rocks mapped at the surface correlate with the already-distinct magnetic anomalies delineated during mapping. The strongest anomalism recorded in the southern central Grønnedal-Ika complex is coincident with the area from where grab samples of magnetite-bearing carbonatite and carbonatite breccia returned total REE (TREE) grades up to 34,468 ppm.
In 2021, a reconnaissance exploration by Eclipse Metals had recorded a strong correlation between REE mineralisation, with grades up to ~3.45% TREE, and the domains of the strongest magnetic anomalies.
Magnetic anomalism was known to be caused by magnetite-bearing carbonatite that was explored in the mid-1900s for its magnetite iron and niobium. Drilling activities were restricted to 6 holes with a downhole length of 750m.
The magnetite is mapped in the EM survey data. On comparison, the size of the magnetic response with the extent of the mapped carbonatite, an extensive potential of carbonatite is indicated.
EM data review
Fathom Geophysics has also concluded a cursory review of the EM data. The review included the digitisation of EM bedrock conductors, which were recorded by the survey contractor at the time of data acquisition.
EM bedrock conductors are agglomerated within the area with the strongest magnetic anomalism in the central section of the Grønnedal-Ika complex. Furthermore, two other clusters of EM bedrock conductors are located outside the Grønnedal-Ika complex and shall be field checked.
The way forward
The latest outcomes provide Eclipse with a new REE targeting model and define targets for follow-up exploration. Eclipse has applied to Mineral Resources Authority to undertake a drilling program at Grønnedal-Ika in 2022. Subsequent steps are -
- Field reconnaissance and grab sampling of magnetic and EM anomalies
- Detailed geological mapping and the relogging of historic drill cores.
- Data integration and interpretation.
- Generation and testing of drill targets.