The eastern Gawler Craton hosts the giant Olympic Dam iron oxide - associated copper-gold (IOCG) deposit, as well as several other world class IOCG deposits (i.e. Prominent Hill and Carrapateena). The region is covered by a thick sequence of...
The eastern Gawler Craton hosts the giant Olympic Dam iron oxide - associated copper-gold (IOCG) deposit, as well as several other world class IOCG deposits (i.e. Prominent Hill and Carrapateena). The region is covered by a thick sequence of Mesoproterozoic to Cenozoic sedimentary and volcanic rocks, making the region difficult and costly to explore using conventional methods. Sets of high quality geoscientific data from the eastern Gawler Craton, such as magnetic, gravity, seismic, radiometric, geological, geochemical, geochronological and hyperspectral data, have been systematically acquired by the Geological Survey of South Australia. Previously these datasets had been looked at independently of each other. Now, however, modern 3D geological mapping and data integration techniques have been adopted by the authors to produce a common earth model of the Emmie Bluff IOCG prospect, that can be readily updated as new data become available. By using this common earth model in conjunction with an understanding of IOCG mineral systems, future explorationists will be able predict where the particular data they are observing lies both spatially and conceptually within the alteration/mineralising system. There are two different styles of IOCG mineral systems which have been active in the eastern Gawler Craton: haematite-dominated systems on the Stuart Shelf, and magnetite-dominated systems on the Yorke Peninsula. For the subject model, UBC gravity and magnetic inversions have been used to map haematite and magnetite alteration in three dimensions, using the method outlined by Williams and Chopping (2009). Chemical modelling of these IOCG mineral systems suggests that high grade mineralisation is likely to form at the haematite/magnetite transition, but the bulk of the mineralisation should occur largely within the haematite zone (Bastrokov, et al., 2007). Multi-element geochemical and spectral mineralogy data have been used to characterise the distribution and degree of development of sericite, chlorite, albite and K-feldspar alteration.
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