SUMMARY

Gossan formations and their meaning in deposit prospecting

Nguyễn Văn Phổ, Nguyễn Văn Lâm

    Gossan - a geological term showing the development of geological formations on sulfide ore bodies through the oxidation of original ores. In gossans, original minerals were washed out and minerals of iron (manganese) hydroxide were accumulated. That’s why they have characteristic yellow-brown and red-brown colours. Remnants of original minerals, however, were remained to create characteristic features (colour, structure and material composition) of gossan.

    Colour is the easiest sign of gossan to observe. But, this is not the confident index sign and we need to pay attention when using it. The structure symbol of gossan is diversified, mainly of residual and colloidal ones. These structures can be used as signs to predict the original minerals.

    The material composition of gossan is the result of moving process of elements. This is the most important and confident signs. While prospecting sulfide ores in humid tropical conditions as in Việt Nam, we can use all above signs of gossan to heighten the effect.

Ngày nhận bài: 10/7/2008

Người nhận xét: Đặng Xuân Phong