Soil air carbon dioxide and oxygen measurements as a guide to concealed mineralization in semi-arid and arid regions

The differences between the CO₂ and O₂ concentrations in soil air and atmospheric air have been measured where sulfide mineralization occurs beneath transported exotic overburden in semi-arid and arid areas of the USA, South West Africa (Namibia) and Saudi Arabia. These mineralizations are reflected near surface by anomalous levels of CO₂ and O₂ in soil air, whereas in most cases heavy-metal anomalies are absent. The normal background variability of CO₂ and O₂ in soil air falls with increasing aridity, and anomaly definition improves with increasing aridity. Thus soil air CO₂ and O₂ data are potentially useful in exploring for concealed mineralization, especially in regions with an arid climate or conspicuous dry season.