Albitite metasomatism and links to copper mineralisation: A case study from the Mt Lofty Ranges
Work with industry to help understand the link between metasomatism, intrusive magmatism and copper mineralisation in the Adelaide Hills.
The metasedimentary sequences of the southern Mt Lofty Ranges are highly prospective for base-metal mineralisation, as best demonstrated by the Kanmantoo Copper deposit that has been mined intermittently for more than 150 years.
Key to developing effective approaches to exploration is a coherent understanding of the origins of mineralisation. However, a number of incompatible models for the origin of mineralisation in the Mt Lofty Ranges have been proposed, including syn-genetic (syn-sedimentary) and post-metamorphic, intrusion-related mineralisation.
Albitites––albite-rich rocks formed by sodic metasomatism––have been recognized across the Mt Lofty Ranges, but particularly in close vicinity to Kanmantoo (see Figure). As well as albite, these rocks may also contain rutile, tourmaline, pyrite and/or magnetite. Albitites have been recognized globally to be associated with large copper deposits (e.g., IOCG systems) and therefore may hold vital clues to the origin of mineralisation at Kanmantoo.
This industry-supported (Hillgrove Resources) honours project will investigate the origin of albitites in the Mt Lofty Ranges using a combination of targeted field mapping, detailed petrography (using both petrographic microscope and electron microprobe), major and trace element mineral chemistry, metasomatic alteration modeling, and, potentially, geochronology (if suitable samples are found). New information gleaned from this study will directly aid understanding of the origins of base metal mineralisation, which will also assist mineral exploration efforts in the region.