The Cainozoic Eucla Basin has been the focus of recent heavy mineral exploration due to the recognition of Tertiary coastal features including the Ooldea Range. Hypsometric and Landsat data, together with detailed work on the Tertiary...
The Cainozoic Eucla Basin has been the focus of recent heavy mineral exploration due to the recognition of Tertiary coastal features including the Ooldea Range. Hypsometric and Landsat data, together with detailed work on the Tertiary stratigraphy of the Basin and surrounding palaeodrainage channels, and on the palaeogeographic setting, has greatly enhanced the search for heavy minerals. Terrigenous sediments of the Immarna Group occur along the eastern margin of the Basin, with the Ooldea Sand and Hampton Sandstone being the main stratigraphic units which host mineralisation. Two heavy mineral strandlines within the Hampton Sandstone were outlined at Immarna by Geopeko. Metallurgical testing showed the deposit comprised predominantly ilmenite, which gave an average TiO2 assay between 61 - 62.1%. Numerous low grade anomalous zones were outlined throughout the Basin, but most drilling was at 1 km intervals and consequently, narrow high grade zones may have been missed. Most exploration focussed on the Ooldea Range and other coastal features including headlands, embayments, strandline beaches, islands and linear shorelines outlined by photogeomorphic mapping. Future exploration for heavy minerals within the Eucla Basin should concentrate on a greater understanding of the stratigraphic distribution of the Eocene Ooldea Sand and Hampton Sandstone, and have a greater emphasis on geomorphic factors including possible provenance areas, besides involving detailed analyses of sediments within palaeodrainage channels to determine flow rates and other factors which influence the transport and concentration of heavy minerals. Potential still exists in areas north and south of the Ooldea Range where the Hampton Sandstone may be closer to the surface, and within the Barton Range. Only limited exploration has been undertaken in the Barton Range. The current market for heavy minerals is depressed with prices reflecting reduced demand and oversupply. However, the market is predicted to improve towards the end of the decade, so the current period is the perfect time to explore for heavy minerals within underexplored areas of the Eucla Basin. With the release of new aeromagnetic data for the north-western Gawler Craton offering new exploration potential, exploration companies should incorporate heavy mineral exploration within future drilling programs in the Eucla Basin.
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