A licence area located near the Birdsville Track, approximately 45 km east of Clayton and 50 km north-east of Marree, was selected because of its perceived potential for having buried occurrences of sediment-hosted uranium mineralisation at...
A licence area located near the Birdsville Track, approximately 45 km east of Clayton and 50 km north-east of Marree, was selected because of its perceived potential for having buried occurrences of sediment-hosted uranium mineralisation at regional redox boundaries and within Cretaceous and / or Cainozoic palaeochannels forming part of an extensive palaeo-drainage system that possibly drained a uranium-rich hinterland (i.e., granite and metamorphic rocks of the Mount Painter Inlier, approximately 100 km south of the Lake Gregory Project licences). The licensee's exploration model is based on analogies with the significant Chu-Saryssu and Syrdarya uranium fields in Kazakhstan, where economic sandstone-hosted uranium deposits were discovered up to 250 km away from the inferred uranium source. The principal target lithologies for the Lake Gregory Project are siliciclastic sedimentary rocks of the Cretaceous Winton and Mackunda Formations, and pyritic and carbonaceous sands of the Paleogene Eyre Formation, which latter unit hosts the significant Honeymoon uranium deposit. Widespread deposited uranium (including XRF assays to 668 ppm U3O8) and subsurface radiation have been documented by Adavale Resources Ltd for the Tertiary Clayton Basin (within EL 3622), which is located immediately south of Regal Point’s EL 3976. During August 2008 the licensee acquired a detailed airborne magnetic and radiometric survey over the entire project area, for 20,683.5 line km coverage along east-west flight lines at 100 m line spacing and 50 m mean sensor height above ground level. The airborne radiometric data for the now relinquished portion of the subject Davis Hill licence show a low tenor response, and the majority of the relinquished ground has a high magnetic intensity which probably reflects shallowly buried Archaean or pre-Neoproterozoic basement in this locality. In the course of a field trip to the licence area undertaken in 2009 it was noted that most locations visited comprise concentrations of ferruginous deflation lag, generally interpreted to have evolved from shales, as reflected in the platy character of the fragments. The lags are both limonitic and coated with vitreous goethitic “desert varnish”. These iron oxides are likely to have captured and concentrated any uranium present in the environment whilst the iron oxides were forming. Only one grab sample of ferruginous indurated sediment material was taken in the now relinquished licence portion, and its assay results included 8 ppm U, 2993 ppm Ba and 3056 ppm V. Filtering enhancement of both the airborne survey data (magnetic, radiometric, topographic) and ASTER satellite remote sensing data imagery was undertaken to try to interpret likely palaeochannel positions and attributes. The interpretation exercise proved difficult, and the level of confidence attributable to the final interpretation of palaeochannel location, geometry and flow direction is low. Problems encountered included inconsistencies between datasets and data variations reflecting present drainage rather than palaeodrainage. The only conclusion made for the relinquished portion of the licence is that the age of its palaeodrainage is unknown, but it is older than Neogene.
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