Geologic, petrographic and tectonic background

Several different tectonic units can be distinguished in southern Malagasy with different rock types and tectonic events. For a more detailed review see Milisenda and Henn (1996). The rock suites in which the mines are situated are explained in more detail hereafter.

Miners working the mine consisting of white skarn

According to Rakotondrazafy et al. (1996) the Andranondambo mine is situated in the metamorphic rocks of the proterozoic Tranomaro group located in the southeast of the island. This rock group consists of varied series of mainly sedimentary origin metamorphosed to granulite facies, such as different gneisses and pyroxene scapolite gneisses, but also calcitic marbles.