Uranium ore-forming systems of the - Geoscience Australia
Uranium ore-forming systems of the - Geoscience Australia
Uranium ore-forming systems of the - Geoscience Australia
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<strong>Uranium</strong> <strong>ore</strong>-<strong>forming</strong> <strong>systems</strong> <strong>of</strong> <strong>the</strong> Lake Frome regionFigure 5.6: Bends in <strong>the</strong> main Yarramba paleochannel (white with red arrow). Note severaltributaries draining in to <strong>the</strong> main channel. Honeymoon deposit is located at <strong>the</strong> bend (circled symbolU). Paleochannel is plotted over gravity (0.5 mgal residual gravity contours). NE trending gravity highcoincides with <strong>the</strong> ridge. Honeymoon deposit is located at <strong>the</strong> faulted breach in <strong>the</strong> ridge. N-trendingtributary south <strong>of</strong> Honeymoon and draining in to <strong>the</strong> main channel crosses uranium-rich granites(roughly coinciding with purple areas on <strong>the</strong> gravity). Source: Skidm<strong>ore</strong> (2005).5.3.3 Honeymoon mineralisation, and oxidation-reduction patternsTabular <strong>ore</strong> zones occur at a depth <strong>of</strong> 110 m below surface and average 4.3 m in thickness (Fig.5.7). The mineralisation is in <strong>the</strong> form <strong>of</strong> microscopic c<strong>of</strong>finite closely associated with humic andpyritic material (McKay and Miezitis, 2001; Skidm<strong>ore</strong>, 2005).Much <strong>of</strong> <strong>the</strong> paleochannel infill sediments appear to have been oxidised with only localoccurrences <strong>of</strong> reduced sands. A roll-front type geometry <strong>of</strong> <strong>the</strong> oxidation-reduction interface hasnot been observed at Honeymoon. The influx <strong>of</strong> oxidised waters in <strong>the</strong> aquifer is still activecausing selective dissolution and removal <strong>of</strong> uranium.Page 63 <strong>of</strong> 151