Why is (geologically speaking) Eastern Congo like Katanga so rich in various ores and (precious) metals?

Answer

To get an idea of ​​the origin of the diversity of different ores in the east of Congo, you have to take into account several factors. Firstly, the eastern part of Congo is a gigantic vast region that stretches over a distance of +/- 1500 km (~ Brussels – South of Spain). The larger the area, the more likely it is to find something. Secondly, this area consists of several fragments that have had different histories. There are rocks present that are more than 2 billion years old, to rocks that are formed recently. So a lot of time has been available to form something. Third, to form an ore deposit, metals must be mobilized, transported and concentrated in a specific place (so-called mineralization). Metals are mobilized under specific chemical-physical conditions and by specific processes, which may differ from metal to metal. For example, a copper-cobalt deposit is formed under different conditions than a tin-coltan deposit. In the eastern DRC, over the course of those two billion years, the conditions in certain geological fragments were ideal for the formation of those metals, while in other fragments the formation of other metals was favored. Moreover, in the same geological block, the conditions may initially be ideal for the formation of those specific metals, while other metals may be formed in the same place at a later period. Fourth: certain metals/minerals also have a tendency to form together, eg copper and cobalt are often formed during the same period and in the same place. In short, the diversity of the ores in eastern DRC is a combination of several factors.

The diversity of different metals in a particular region is not that exceptional in the world and is often recognized in older geological areas where different parts have been active during different periods (eg certain areas Australia, Canada, South Africa, etc).