CRC LEME
Open File Report 52
ABSTRACT
The distribution of gold and other elements in soils and vegetation
at Zuleika, Western Australia
Lintern, M.J. and Butt, C.R.M.
This report describes an investigation of a possible surface expression
of the Zuleika Sands Au deposits, south of Ora Banda. The deposits
are situated within and beneath the sediments of a palaeochannel
in a floodplain adjacent to a low rise and pediplain with residual
soils. Gold mineralization occurs semi-continuously in the basal
sands of the palaeochannel and the underlying saprolite. A variety
of sample media were selected, including different soil horizons,
surface lag, and vegetation, and analysed for Au and a range of
other elements.
Anomalous Au concentrations (mean 28 ppb) were found in calcareous
surficial horizons (0 - 1 m) directly overlying the buried mineralization,
compared to a mean background of 13 ppb over barren sediments. However,
much higher concentrations (mean 141 ppb) are present in equivalent
horizons of residual soils associated with subcropping mineralisation
on the low rise. Because of the proximity of the two areas, it is
possible that the anomalies in the floodplain could be derived from
down-slope dispersion from the residual areas, so that no unequivocal
demonstration of the surface expression of the buried mineralization
was possible. However, it is known that similar mineralization elsewhere,
buried beneath over 20 m of barren sediments and leached saprolite,
does give rise to soil anomalies. Gold distributions within topsoils
and vegetation were similar to those shown by the calcareous horizon
but that of lag was more erratic, with the highest values over the
floodplain, suggesting a clastic derivation from the north.
Last updated: Thursday, January 06, 2000 08:58 AM
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