Eclipse Metals Ltd (ASX: EPM) has identified a number of follow-up targets following a recently completed re-interpretation of geophysical data over the Gronnedal-lka area within the Ivittuut Project tenement, MEL2007/45, in Greenland.
The aim of the programme was to identify new magnetic/EM anomalies that shared similar geophysical signatures with known mineralisation in other major mineral deposits within the Gardar Province.
The project tenement is considered to be highly prospective for rare earth elements (REE). Core Geophysics were commissioned to obtain available open file geophysical datasets, process the data and make initial comment on the data for REE, magnetite and massive sulphide exploration potential. This work has provided a significant amount of information on prospectivity of the carbonatite occurrence and mafic dykes.
Most recent geophysical surveys over the project (circa 1980+) have been captured by the Geological Survey of Denmark and Greenland (GEUS) and include regional surveys commissioned by the government and those conducted by exploration companies.
The most relevant datasets are the 1995 GEUS aeromagnetic survey (TMI) flown at 500m line spacing and a Dighem airborne electromagnetic survey flown at 200m line spacing by Diamond Field Resources in 1995. The survey was flown by helicopter over areas off the inland ice/glacier following topographic contours with flight traverses from 2km to 5km apart. The data has been captured by digitising maps generated at the time and can be used as a guide only.
The 1995 Dighem survey contains both magnetic and electromagnetic data. The magnetic data from the Dighem survey was processed and imaged individually as well as being merged together with the GEUS magnetic dataset. The data has been processed and imaged in an attempt to highlight and better define controlling structures including shears, faults and lithological variations. Data processing included calculation of the first and second vertical derivatives and tilt derivatives, with all magnetic data reduced to the pole.
Data from historic radiometric surveys (Syduran Project) collected in 1979-1980 was also studied.
The 1995 magnetic data provides the best coverage and resolution over the project tenement. The strongest magnetic responses are evident in the eastern portion of the tenement and are closely associated with carbonatite and gabbro bodies as mapped in the 1:100,000 geology series.
The strong magnetic response suggests a high magnetite concentration at these sites. The magnetics also highlight numerous north-east and east-west trending (gabbroic) dykes of which only some appear in the 1:100,000 mapping.
The magnetic data highlights two ovoid shaped responses associated with the carbonatite bodies. Comparing the size of the magnetic response with the extent of the mapped carbonatite, suggests there is a larger potential extent of carbonatite than indicated by earlier mapping.
The Ivittuut mine appears to lie on the edge of a large circular magnetic low indicated in the regional survey which represents a granitic intrusive body. Data resolution in the immediate vicinity of the mine is too coarse to define any small-scale features which may characterise the response of the intrusion.
The Dighem electromagnetic data has defined seven conductive zones. These are likely sourced from either sulphide minerals or magnetite, which can also produce a conductivity-like response in frequency domain EM systems.
Large strongly conductive zones along the western and south eastern areas of the survey are due to sea water in the fjords. Target zones have been outlined over the stronger conductors and are recommended for follow up investigation,
Gabbroic dykes have been the subject of base metal exploration programmes in the region, with MDA investments discovering Ni sulphides at Discovery Dyke approximately 30km to the south. The Dighem survey has defined a number of conductive targets which may represent sulphide or possibly magnetite sources.
It has also been recommended that additional, higher resolution surveys be conducted over the project tenement.
