CRC LEME
Open File Report 15
ABSTRACT
Mineralogy and geochemistry of some weathered rocks from Callion
Gold Deposit, Yilgarn Block, WA
Llorca, S.M.
Weathered profiles at Callion are the host of economic gold mineralization.
This report starts the documentation of these profiles, which ultimately
will enable us to understand the weathering processes and the distribution
of gold and associated elements in the weathered profile. Data reported
here concern the mineralogy and geochemistry of the upper weathered
wall-rocks from the BC Pit at the northern end of the Callion mineralization.
Two geological formations were characterised, showing slightly
different compositions.
The in-situ weathered rock is essentially composed of kaolinite
and quartz gradually replaced by goethite. With the progressive
decrease of Al and Si and the concentration of Fe, we observed a
progressive dispersion of Ti, Mg, K, Na, Cl, Sr and Y and concentration
of S and Cu.
An allochthonous formation at the northern end of the BC pit is
composed mainly of hematite, goethite and alunite. In this formation,
Si, Ba, Cu and Zn show a depletion whereas Ti, S, CO2, As, Cr and
Zr are concentrated. The presence of alunite indicates the presence,
at some stage, of sulphate-rich groundwaters.
Last updated: Tuesday, January 04, 2000 12:33 PM
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