EARTH SCIENCES DEPARTMENT SEMINAR
The roles of paleoclimates, mineralogy and geochemistry in forming anomalies on interfaces in areas of basin cover: implications for exploration
CSIRO Earth Science and Resource Engineering, Western Australia
Wednesday 10th April - 12.00
Mineralogy Seminar Room
Transported cover provides significant challenges to geochemical exploration as dispersion of indicator elements to the surface is restricted. Conventional approaches (e.g. soil and lag sampling) may not be viable in many areas of transported cover and various selective extraction methods have had only limited success in deeply weathered and arid terrains than in terrains with recent glacial or volcanic cover. An alternative approach to the direct detection of element dispersion from mineralisation through transported regolith is the identification of the more general effects of oxidising sulphide mineralisation on regolith mineralogy and pH. Approaches to detect these features have been developed, but their application has met with limited success.
In Australia, exploration is progressively moving to areas of deep transported cover (>30 m). Given the cost of deep drilling, high density sampling of weathered basement beneath the unconformity is no longer cost effective and so new exploration approaches are needed. A variety of transported cover sediments, ranging from Quaternary to Permian, are common in Australian landscapes. These have been subjected to weathering under a variety of climates. The Quaternary climate differed from Tertiary and Cretaceous climates, resulting in distinct styles of weathering and mineralogical features. This presentation provides a synthesis on the importance of an integrated approach combining different metal migration mechanisms with the nature of transported regolith, landscape history and climate settings to obtain the best prediction of anomaly formation and guide exploration strategies.
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