The Vallée des Couleurs is endowed with a wide stretch of multiple coloured earths arranged in bands and domes. Some 23 coloured earths have been identified and scientifically described.
The vallée des Couleurs is located around 1 km downstream to the south east of Bassin Blanc volcano which was in eruption some 100, 000 years ago making it one of the most recent and young volcanoes of the Island. The particularity of Bassin Blanc volcano is that it was of the strombolian type i.e it was slightly explosive due to the presence of underground water near the active vent of the volcanic structure.
This means that for more than one hundred thousand years, the volcano has been emitting pyroclastic materials (pyro means fire and clastic means broken) ranging from clinkers to lapilli, tuffs, cinders and volcanic ash. Millions of tons of volcanic ash of different metallic composition and chemical characteristics have been emitted and have carpeted the region south and East of Basin Blanc.