Determination of the geochemical background and anomalies in areas with variable lithologies

- First study of anomaly threshold determination by residual error confidence band
- Mathematical description of relationship between metallogenic elements and SiO2
- Weak anomalies were delineated without losing information of known deposits.

Studies that delineate the geochemical background and anomalies are essential for exploration geochemistry. Lithology has a significant impact on the background values of many elements in both stream sediments and soil samples. However, uniform threshold values are not available for delineation of all anomalies in areas with complex geologic conditions. Here, the influence of lithology on background concentrations of metals is described based on the relationships between metal element concentrations and oxide concentrations (in particular SiO2) in geochemical samples. The anomaly thresholds of metal elements, influenced by lithology, can be determined from the residual error confidence band based on a linear regression model. This method can help eliminate the influence of lithology on background concentrations of metals and allows more effective detection of anomalies than a simple constant threshold method.