- journal_title：Geochemistry ; Exploration ; Environment ; Analysis
- Contributor：Paul A. Morris
- Publisher：Geological Society of London
- Date：2013-02-01
- Format：text/html
- Language：en
- Identifier：10.1144/geochem2012-141
- journal_abbrev：Geochemistry: Exploration, Environment, Analysis
- issn：1467-7873
- volume：13
- issue：1
- firstpage：21
- section：Thematic set article
The fine fraction (<50 μm; ‘silt – clay’) of regolith from an area dominated by thick (up to 120 m) transported regolith is shown to be a viable sampling medium for detecting bedrock and bedrock-hosted mineralization. A partial digest of the fine fraction of regolith reveals that elements which have migrated vertically from bedrock have become sequestered at a shallow depth in regolith. Nickel, Cr, Li, Mn, V, Co and Rb are useful in tracing the extent of different bedrock types, with Ni, Cr, V and Co particularly useful for identifying more mafic bedrock. Higher concentrations of Au (maximum 29 ppb; median 2 ppb; n = 835) are spatially related to either Archean greenstones or unconformity-related uranium – base metal – gold mineralization. Although some samples with anomalous Au concentrations are carbonate-rich, there is no consistent relationship between elevated Au concentrations and the carbonate content of regolith. Deionized water digestion of the <50-μm fraction of 50 samples correlates with aqua regia data for several elements (particularly Au, Ni), suggesting that some mineralization- or bedrock-related elements in the fine fraction of regolith are either labile or microparticulate.