Gossans and leached cappings. Field assessment / Железные шляпы и зоны окисления. Полевые работы

This text is aimed at recognition, fi eld procedures and interpretation of gossanleached outcrops as they appear on the surface; however it is obviously useful for the observer to have a working concept of the factors controlling development. The origin and nature of gossans / leached cappings have long been of interest to both the practical and scientifi c communities, and it is now well known that diff erent sets of circumstances will results in diff erent end products.
Th e gossan / leached capping formation process commences when ore assemblages and their associated wall rocks encounter the interface between the water table and the overlying surfi cial zone. Th is is in essence the transition from a reducing to an oxidising environment.
As the ore assemblages transition from the water table to surface via weathering, there are numerous factors which contribute to the fi nal surface exposure. <...>