Uranium ore-forming systems of the - Geoscience Australia

Uranium ore-forming systems of the Lake Frome regionLocality 14 (353980E ; 6664830N) Four Mile Creek - Dead Tree SectionA key stratigraphic section adjacent to the Four Mile West uranium mineralisation has recently beenrecognised by University of Adelaide and PIRSA researchers within an ephemeral stream tributaryof Four Mile Creek. This section includes:the basal Mesozoic lithic gravels (possibly equivalent to the Algebuckina Sandstone);a complete sequence of Eyre Formation sediments extending from the basal quartzosegravel, through sediments laterally equivalent to those that host the Four Milemineralisation and the uppermost pedogenic silcrete (equivalent to the 'Cordillo Silcrete');and,Lower energy proximal fluvial sands of the Namba Formation.The sedimentary section extends for over 150 m and may contain evidence of cryptic signaturesrelating to fluid migration and residence associated with the Four Mile mineralisation. The exposedsediments are now oxidised and therefore any prospect of hosting significant uranium mineralisationis low. However because parts of this sequence are laterally equivalent to the adjacent Four Milemineralisation they may have previously hosted mineralisation.The compilation and description of this section is presently being finalised by Steve Hill (Universityof Adelaide) and Steve Hore (PIRSA) and is due for submission for publication in 2009.Page 139 of 151