Apatite fission track and U-Pb mapping of the northern Gawler Craton: implications for ore deposit exhumation and preservation

Glorie, Stijn1; Reid, Anthony1,2; Hall, James1; Nixon, Angus1; Collins, Alan1

1The University of Adelaide, Department of Earth Sciences, Adelaide, Australia; 2Geological Survey of South Australia, Department for Energy and Mining, GPO Box 320, Adelaide, Australia

The formation of major Palaeoproterozoic and Mesoproterozoic (Cu)-Au deposits at the metal-rich margins of the Gawler Craton, South Australia, has received a lot of attention, however, the relationships between metal occurrences, the exhumation level of the crust and the structural architecture of the craton margins are less clear. Here, we present results from apatite fission track and U-Pb thermochronology applied to basement rocks at the northern margin of the Gawler Craton. Resulting age interpolation maps reveal differential cooling histories with respect to major structures such as the Karari Shear Zone. Furthermore, the extent of Phanerozoic exhumation shows a spatial relation with the location of Au (and/or Cu, Fe) mineralization in the northern Gawler Craton. Areas that were significantly modified by Mesoproterozoic mineralizing events, such as the Olympic IOCG province and the Central Gawler Gold Province, record post-Silurian exhumation histories related to the Alice Springs Orogeny. To the west of these two major mineral provinces, Archaean – early Palaeoproterozoic terranes in the northwestern Gawler Craton with abundant Au (and Cu, Fe) mineral occurrences were not affected by Phanerozoic exhumation and denudation. These relations suggest that Mesoproterozoic fluids might have weakened the Gawler Craton, making the mineralized terranes were more susceptible to Phanerozoic deformation compared to the Archaean – Palaeoproterozoic terranes within the stronger parts of the Gawler Craton. Hence, understanding the timing of fault reactivation and the associated relative exhumation level may provide valuable constraints for ore deposit preservation and mineral exploration within the Gawler Craton.


Biography

Stijn Glorie completed a PhD in Geology in 2012, followed by a short post-doctoral fellowship at Ghent University, on intracontinental deformation within Central Asia. In March 2013, he was appointed as a Lecturer and in 2015 he was promoted to Senior Lecturer at The University of Adelaide.

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