The morphology and geochemistry of gold grains have been studied at different levels of the lateritic profile in the Zoroastrian Pit at Bardoc. Some grains are strongly corroded whereas others are quite well preserved and it can be assumed that there are several generations of secondary gold grains.
Secondary gold does, however, contain traces of iron, probably as micro-inclusions of iron oxide.
The observed gold distribution is probably the result of two mechanisms of chemical dispersion. Gold remobilisation first occurred during lateritization, principally in the ferruginous horizon, but dissolution was not complete. The second phase was during a later, arid period when gold was strongly dissolved by saline groundwaters and dispersed in the saprolite and mottled clay zone.