Uranium Metallogeny In The North Flinders Ranges: South Australia

The North Flinders Ranges show uranium mineralisations in both basement and nearby Lake Frome sediments. Mostly based on U-Pb LA-ICPMS geochronology and mineralogy of U-Th-REE phases, we documented major stages of mobility: (1) intrusion of A-type Mesoproterozoic granites (1575-1560 Ma) with high HFSE contents (including rare metal Yerila granite); (2) late- or post-magmatic metasomatism in the granites (1565-1521) by alkaline oxidising F-rich fluids evidenced by Y-rich Al-F-titanite, fluorapatite and synchysite. The metasomatism also formed REE-rich skarns around the granites (~1501 Ma); (3) Cambrian Delamerian amphibolite-facies metamorphism lead to widespread crystallisation of monazite and xenotime peaking at ~490 Ma; (4) anatexis of buried basement during Ordovician generated Y-U-enriched peraluminous British Empire granite (453-459 Ma); (5) hydrothermal/pegmatitic U remobilisation occurred along active faults during stages of uplifting (brannerite veins at 367 Ma) and active hydrothermalism occurred around the Mt Gee during Permian (~290 Ma); (6) U-rich oxidised groundwaters moved into the Lake Frome basin during Cenozoic, precipitating uranium in the sands (6.7-3.4 Ma).